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Proe KR, Towarnicky A, Fertig A, Lu Z, Mpourmpakis G, Matson EM. Impact of Surface Ligand Identity and Density on the Thermodynamics of H Atom Uptake at Polyoxovanadate-Alkoxide Surfaces. Inorg Chem 2024; 63:7206-7217. [PMID: 38592922 DOI: 10.1021/acs.inorgchem.3c04435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/11/2024]
Abstract
An understanding of how molecular structure influences the thermodynamics of H atom transfer is critical to designing efficient catalysts for reductive chemistries. Herein, we report experimental and theoretical investigations summarizing structure-function relationships of polyoxovanadate-alkoxides that influence bond dissociation free energies of hydroxide ligands located at the surface of the cluster. We evaluate the thermochemical descriptors of O-H bond strength for a series of clusters, namely [V6O13-x(OH)x(TRIOLR)2]-2 (x = 2, 4, 6; R = NO2, Me) and [V6O11-x(OMe)2(OH)x(TRIOLNO2)2]-2, via computational analysis and open circuit potential measurements. Our findings reveal that modifications to the TRIOL ligand (e.g., changing from the previously reported electron withdrawing nitro-backed ligand to the electron-donating methyl variant) have limited influence on the strength of surface O-H bonds as a result of near complete thermodynamic compensation in these systems (i.e., correlated changes in redox potential and cluster basicity). In contrast, changes in surface density of alkoxide ligands via direct alkoxylation of the polyoxovanadate-alkoxide surface result in measurable increases in bond dissociation free energies of surface O-H bonds for the mixed-valent derivatives. Our findings indicate that the extent of (de)localization of electron density across the cluster core has an impact on the bond dissociation free energies of surface O-H bonds across all oxidation states of the assembly.
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Affiliation(s)
- Kathryn R Proe
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - Andreas Towarnicky
- Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Alex Fertig
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - Zhou Lu
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - Giannis Mpourmpakis
- Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Ellen M Matson
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
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2
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Spencer MA, Holzapfel NP, You KE, Mpourmpakis G, Augustyn V. Participation of electrochemically inserted protons in the hydrogen evolution reaction on tungsten oxides. Chem Sci 2024; 15:5385-5402. [PMID: 38577375 PMCID: PMC10988594 DOI: 10.1039/d4sc00102h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2024] [Accepted: 03/07/2024] [Indexed: 04/06/2024] Open
Abstract
Understanding the mechanisms by which electrodes undergo the hydrogen evolution reaction (HER) is necessary to design better materials for aqueous energy storage and conversion. Here, we investigate the HER mechanism on tungsten oxide electrodes, which are stable in acidic electrolytes and can undergo proton-insertion coupled electron transfer concomitant with the HER. Electrochemical characterization showed that anhydrous and hydrated tungsten oxides undergo changes in HER activity coincident with changes in proton composition, with activity in the order HxWO3·H2O > HxWO3 > HxWO3·2H2O. We used operando X-ray diffraction and density functional theory to understand the structural and electronic changes in the materials at high states of proton insertion, when the oxides are most active towards the HER. H0.69WO3·H2O and H0.65WO3 have similar proton composition, structural symmetry, and electronic properties at the onset of the HER, yet exhibit different activity. We hypothesize that the electrochemically inserted protons can diffuse in hydrogen bronzes and participate in the HER. This would render the oxide volume, and not just the surface, as a proton and electron reservoir at high overpotentials. HER activity is highest in HxWO3·H2O, which optimizes both the degree of proton insertion and solid-state proton transport kinetics. Our results highlight the interplay between the HER and proton insertion-coupled electron transfer on transition metal oxides, many of which are non-blocking electrodes towards protons.
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Affiliation(s)
- Michael A Spencer
- Department of Materials Science and Engineering, North Carolina State University 911 Partners Way Raleigh NC 27606 USA
| | - Noah P Holzapfel
- Department of Materials Science and Engineering, North Carolina State University 911 Partners Way Raleigh NC 27606 USA
| | - Kyung-Eun You
- Department of Chemical and Petroleum Engineering, University of Pittsburgh Pittsburgh PA 15260 USA
| | - Giannis Mpourmpakis
- Department of Chemical and Petroleum Engineering, University of Pittsburgh Pittsburgh PA 15260 USA
| | - Veronica Augustyn
- Department of Materials Science and Engineering, North Carolina State University 911 Partners Way Raleigh NC 27606 USA
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3
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Salem M, Loevlie DJ, Mpourmpakis G. Single Atom Alloys Segregation in the Presence of Ligands. J Phys Chem C Nanomater Interfaces 2023; 127:22790-22798. [PMID: 38037638 PMCID: PMC10683009 DOI: 10.1021/acs.jpcc.3c05827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 10/22/2023] [Accepted: 10/24/2023] [Indexed: 12/02/2023]
Abstract
Single atom alloys (SAAs) have gained remarkable attention due to their tunable properties leading to enhanced catalytic performance, such as high activity and selectivity. The stability of SAAs is dictated by surface segregation, which can be affected by the presence of surface adsorbates. Research efforts have primarily focused on the effect of commonly found catalytic reaction intermediates, such as CO and H, on the stability of SAAs. However, there is a knowledge gap in understanding the effect of ligands from colloidal nanoparticle (NP) synthesis on surface segregation. Herein, we combine density functional theory (DFT) and machine learning to investigate the effect of thiol and amine ligands on the stability of colloidal SAAs. DFT calculations revealed rich segregation energy (Eseg) data of SAAs with d8 (Pt, Pd, Ni) and d9 (Ag, Au, Cu) metals exposing (111) and (100) surfaces, in the presence and absence of ligands. Using these data, we developed an accurate four-feature neural network using a multilayer perceptron regression (NN MLP) model. The model captures the underlying physics behind surface segregation in the presence of adsorbed ligands by incorporating features representing the thermodynamic stability of metals through the bulk cohesive energy, structural effects using the coordination number of the dopant and the ligands, the binding strength of the adsorbate to the metals, strain effects using the Wigner-Seitz radius, and electronic effects through electron affinities. We found that the presence of ligands makes the thermodynamics of segregation milder compared to the bare (nonligated) SAA surfaces. Importantly, the adsorption configuration (e.g., top vs bridge) and the binding strength of the ligand to the SAA surface (e.g., amines vs thiols) play an important role in altering the Eseg trends compared to the bare surface. We also developed an accurate NN MLP model that predicts Eseg in the presence of ligands to find thermodynamically stable SAAs, leading to the rapid and efficient screening of colloidal SAAs. Our model captures several experimental observations and elucidates complex physics governing segregation at nanoscale interfaces.
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Affiliation(s)
- Maya Salem
- Department of Chemical and Petroleum
Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Dennis J. Loevlie
- Department of Chemical and Petroleum
Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Giannis Mpourmpakis
- Department of Chemical and Petroleum
Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
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4
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Nilsson S, El Berch JN, Albinsson D, Fritzsche J, Mpourmpakis G, Langhammer C. The Role of Grain Boundary Sites for the Oxidation of Copper Catalysts during the CO Oxidation Reaction. ACS Nano 2023; 17:20284-20298. [PMID: 37796938 PMCID: PMC10604102 DOI: 10.1021/acsnano.3c06282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 09/28/2023] [Indexed: 10/07/2023]
Abstract
The oxidation of transition metal surfaces is a process that takes place readily at ambient conditions and that, depending on the specific catalytic reaction at hand, can either boost or hamper activity and selectivity. Cu catalysts are no exception in this respect since they exhibit different oxidation states for which contradicting activities have been reported, as, for example, in the catalytic oxidation of CO. Here, we investigate the impact of low-coordination sites on nanofabricated Cu nanoparticles with engineered grain boundaries on the oxidation of the Cu surface under CO oxidation reaction conditions. Combining multiplexed in situ single particle plasmonic nanoimaging, ex situ transmission electron microscopy imaging, and density functional theory calculations reveals a distinct dependence of particle oxidation rate on grain boundary density. Additionally, we found that the oxide predominantly nucleates at grain boundary-surface intersections, which leads to nonuniform oxide growth that suppresses Kirkendall-void formation. The oxide nucleation rate on Cu metal catalysts was revealed to be an interplay of surface coordination and CO oxidation behavior, with low coordination favoring Cu oxidation and high coordination favoring CO oxidation. These findings explain the observed single particle-specific onset of Cu oxidation as being the consequence of the individual particle grain structure and provide an explanation for widely distributed activity states of particles in catalyst bed ensembles.
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Affiliation(s)
- Sara Nilsson
- Department
of Physics, Chalmers University of Technology, 412 96 Göteborg, Sweden
| | - John N. El Berch
- Department
of Chemical and Petroleum Engineering, University
of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - David Albinsson
- Department
of Physics, Chalmers University of Technology, 412 96 Göteborg, Sweden
| | - Joachim Fritzsche
- Department
of Physics, Chalmers University of Technology, 412 96 Göteborg, Sweden
| | - Giannis Mpourmpakis
- Department
of Chemical and Petroleum Engineering, University
of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Christoph Langhammer
- Department
of Physics, Chalmers University of Technology, 412 96 Göteborg, Sweden
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5
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Miu EV, McKone JR, Mpourmpakis G. Global and Local Connectivities Describe Hydrogen Intercalation in Metal Oxides. Phys Rev Lett 2023; 131:108001. [PMID: 37739359 DOI: 10.1103/physrevlett.131.108001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 05/18/2023] [Accepted: 07/28/2023] [Indexed: 09/24/2023]
Abstract
We introduce global connectivity, Ω, which quantifies the detailed connectivity of a material and accurately captures reactivity behavior. We demonstrate that combining global and local connectivity describes how metal oxides interact with hydrogen. Blending density functional theory, graph theory, and machine learning we built a reactivity model which accurately predicts hydrogen intercalation potentials of different metal oxides experimentally measured in the lab. The use of global connectivity can accelerate materials design through the development of novel structure-property relationships.
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Affiliation(s)
- Evan V Miu
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15216
| | - James R McKone
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15216
| | - Giannis Mpourmpakis
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15216
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6
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Leung KC, Hong S, Li G, Xing Y, Ng BKY, Ho PL, Ye D, Zhao P, Tan E, Safonova O, Wu TS, Li MMJ, Mpourmpakis G, Tsang SCE. Confined Ru Sites in a 13X Zeolite for Ultrahigh H 2 Production from NH 3 Decomposition. J Am Chem Soc 2023. [PMID: 37343126 DOI: 10.1021/jacs.3c05092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/23/2023]
Abstract
Catalytic NH3 synthesis and decomposition offer a new promising way to store and transport renewable energy in the form of NH3 from remote or offshore sites to industrial plants. To use NH3 as a hydrogen carrier, it is important to understand the catalytic functionality of NH3 decomposition reactions at an atomic level. Here, we report for the first time that Ru species confined in a 13X zeolite cavity display the highest specific catalytic activity of over 4000 h-1 for the NH3 decomposition with a lower activation barrier, compared to most reported catalytic materials in the literature. Mechanistic and modeling studies clearly indicate that the N-H bond of NH3 is ruptured heterolytically by the frustrated Lewis pair of Ruδ+-Oδ- in the zeolite identified by synchrotron X-rays and neutron powder diffraction with Rietveld refinement as well as other characterization techniques including solid-state nuclear magnetic resonance spectroscopy, in situ diffuse reflectance infrared transform spectroscopy, and temperature-programmed analysis. This contrasts with the homolytic cleavage of N-H displayed by metal nanoparticles. Our work reveals the unprecedented unique behavior of cooperative frustrated Lewis pairs created by the metal species on the internal zeolite surface, resulting in a dynamic hydrogen shuttling from NH3 to regenerate framework Brønsted acid sites that eventually are converted to molecular hydrogen.
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Affiliation(s)
- Kwan Chee Leung
- Wolfson Catalysis Centre, Department of Chemistry, University of Oxford, Oxford OX1 3QR, U.K
| | - Sungil Hong
- Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Guangchao Li
- Wolfson Catalysis Centre, Department of Chemistry, University of Oxford, Oxford OX1 3QR, U.K
- Department of Applied Physics, Hong Kong Polytechnic University, Hong Kong, P. R. China
| | - Youdong Xing
- Department of Applied Physics, Hong Kong Polytechnic University, Hong Kong, P. R. China
| | - Bryan Kit Yue Ng
- Wolfson Catalysis Centre, Department of Chemistry, University of Oxford, Oxford OX1 3QR, U.K
| | - Ping-Luen Ho
- Wolfson Catalysis Centre, Department of Chemistry, University of Oxford, Oxford OX1 3QR, U.K
| | - Dongpei Ye
- Wolfson Catalysis Centre, Department of Chemistry, University of Oxford, Oxford OX1 3QR, U.K
| | - Pu Zhao
- Wolfson Catalysis Centre, Department of Chemistry, University of Oxford, Oxford OX1 3QR, U.K
| | - Ephraem Tan
- Wolfson Catalysis Centre, Department of Chemistry, University of Oxford, Oxford OX1 3QR, U.K
| | - Olga Safonova
- Paul Scherrer Institut, WLGA/217, Forschungsstrasse 111, 5232 Villigen PSI, Switzerland
| | - Tai-Sing Wu
- National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
| | - Molly Meng-Jung Li
- Department of Applied Physics, Hong Kong Polytechnic University, Hong Kong, P. R. China
| | - Giannis Mpourmpakis
- Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Shik Chi Edman Tsang
- Wolfson Catalysis Centre, Department of Chemistry, University of Oxford, Oxford OX1 3QR, U.K
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7
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Kwon H, Mpourmpakis G. Ab Initio Thermochemistry of Highly Flexible Molecules for Thermal Decomposition Analysis. J Chem Theory Comput 2023. [PMID: 37310272 DOI: 10.1021/acs.jctc.3c00265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Pyrolysis is a promising technology for chemical recycling of waste plastics, since it enables the generation of high-value chemicals with low capital and operating cost. The calculation of thermodynamic equilibrium composition using the Gibbs free energy minimization approach can determine pyrolysis operating conditions that produce desired products. However, the availability of thermochemical data can limit the application of equilibrium calculations. While density functional theory (DFT) calculations have been commonly used to produce accurate thermochemical data (e.g., enthalpies of formation) of small molecules, the accuracy and computational cost of these calculations are both challenging to handle for large, flexible molecules, exhibiting multiple conformations at elevated (i.e., pyrolysis) temperatures. In this work, we develop a computational framework to calculate accurate, temperature-dependent thermochemistry of large and flexible molecules by combining force field based conformational search, DFT calculations, thermochemical corrections, and Boltzmann statistics. Our framework produces accurately calculated thermochemistry that is used to predict equilibrium thermal decomposition profiles of octadecane, a model compound of polyethylene. Our thermochemistry results are compared against literature data demonstrating a great agreement, and the predicted decomposition profiles rationalize a series of pyrolysis experimental observations. Our work systematically addresses entropic contributions of large molecules and suggests paths for accurate and yet computationally feasible calculations of Gibbs free energies. The first-principles-based thermodynamic equilibrium analysis proposed in this work can be a significant step toward predicting temperature-dependent product distributions from plastic pyrolysis and guide experimentation on chemical plastic recycling.
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Affiliation(s)
- Hyunguk Kwon
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Giannis Mpourmpakis
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
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8
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Liu R, El Berch JN, House S, Meil SW, Mpourmpakis G, Porosoff MD. Reactive Separations of CO/CO 2 mixtures over Ru–Co Single Atom Alloys. ACS Catal 2023. [DOI: 10.1021/acscatal.2c05110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Renjie Liu
- Department of Chemical Engineering, University of Rochester, Rochester, New York14627, United States
| | - John N. El Berch
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania15261, United States
| | - Stephen House
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania15261, United States
- Environmental TEM Catalysis Consortium (ECC), University of Pittsburgh, Pittsburgh, Pennsylvania15261, United States
- Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, New Mexico87123, United States
| | - Samuel W. Meil
- Department of Chemical Engineering, University of Rochester, Rochester, New York14627, United States
| | - Giannis Mpourmpakis
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania15261, United States
| | - Marc D. Porosoff
- Department of Chemical Engineering, University of Rochester, Rochester, New York14627, United States
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9
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Hong S, Mallette AJ, Neeway JJ, Motkuri RK, Rimer JD, Mpourmpakis G. Understanding formation thermodynamics of structurally diverse zeolite oligomers with first principles calculations. Dalton Trans 2023; 52:1301-1315. [PMID: 36625388 DOI: 10.1039/d2dt02764j] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The mechanisms of many zeolitic processes, including nucleation and interzeolite transformation, are not fully understood owing to complex growth mixtures that obfuscate in situ monitoring of molecular events. In this work, we provide insights into zeolite chemistry by investigating the formation thermodynamics of small zeolitic species using first principles calculations. We systematically study how formation energies of pure-silicate and aluminosilicate species differ by structure type and size, temperature, and the presence of alkali or alkaline earth metal cations (Na+, K+, and Ca2+). Highly condensed (cage-like) species are found to be strongly preferred to simple rings in the pure-silicate system, and this thermodynamic preference increases with temperature. Introducing aluminum leads to more favorable formation thermodynamics for all species. Moreover, for species with a low Si/Al ratio (≤2), a thermodynamic preference does not exist among structure types; instead, a pool of diverse aluminosilicate structures compete in formation. Metal cation effects strongly depend on the presence of aluminum, cage size, cation type, and location, since each of these factors can alter electrostatic interactions between cations and zeolitic species. We reveal that confined metal cations may destabilize pure-silicate cages due to localized interactions; conversely, they stabilize aluminosilicates due to strong cation-framework attractions in sufficiently large cages. Importantly, this work rationalizes a series of experimental observations and can potentially guide efforts for controlling zeolite nucleation/crystallization processes.
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Affiliation(s)
- Sungil Hong
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA, 15261, USA.
| | - Adam J Mallette
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX, 77204, USA
| | - James J Neeway
- Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, WA, 99352, USA
| | - Radha Kishan Motkuri
- Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, WA, 99352, USA
| | - Jeffrey D Rimer
- Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX, 77204, USA
| | - Giannis Mpourmpakis
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA, 15261, USA.
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10
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Loevlie D, Ferreira B, Mpourmpakis G. Demystifying the Chemical Ordering of Multimetallic Nanoparticles. Acc Chem Res 2023; 56:248-257. [PMID: 36680516 PMCID: PMC9910050 DOI: 10.1021/acs.accounts.2c00646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
ConspectusMultimetallic nanoparticles (NPs) have highly tunable properties due to the synergy between the different metals and the wide variety of NP structural parameters such as size, shape, composition, and chemical ordering. The major problem with studying multimetallic NPs is that as the number of different metals increases, the number of possible chemical orderings (placements of different metals) for a NP of fixed size explodes. Thus, it becomes infeasible to explore NP energetic differences with highly accurate computational methods, such as density functional theory (DFT), which has a high computational cost and is typically applied to up to a couple of hundred metal atoms. Here, we demonstrate a methodology advancing NP simulations by effectively exploring the vast materials space of multimetallic NPs and accurately identifying the ones with the most thermodynamically preferred chemical orderings. With accuracies reaching that of DFT, our methodology is applicable to practically any NP size, shape, and metal composition. We achieve this by significantly advancing the bond-centric (BC) model, a physics-based model that has been previously shown to rapidly predict bimetallic NP cohesive energies (CEs). Specifically, the BC model is trained in a way to understand how the bimetallic bond strength changes under different coordination environments present on a NP and how the metal composition of every site affects the detailed coordination environment using fractional coordination numbers. This newly modified BC model leads to an improvement from 0.331 (original model) to 0.089 eV/atom in CE predictions when compared to DFT values on a robust data set of 90 different NPs consisting of PtPd, AuPt, and AuPd NPs with varying compositions and chemical orderings. By incorporating the modified BC model into an in-house-developed genetic algorithm (GA) we can effectively and accurately predict the most stable chemical orderings of large, realistic bimetallic NPs consisting of thousands of metal atoms. This is demonstrated on AuPd bimetallic NPs, a challenging system due to the similarity in the cohesion of the two metals. By training our BC model using a unique DFT calculation on a bimetallic NP (one calculation for two metals combining together), we expand to explore the chemical ordering of multimetallic NPs. We first demonstrate the application of our methodology on a AuPdPt NP and validate our stability predictions with literature data. Then, we effectively explore the vast materials space of multimetallic NPs consisting of combinations of Au, Pt, and Pd as a function of metal composition. Our thermodynamic stability trends are presented in a ternary diagram revealing detailed, and yet, unexpected chemical ordering trends. Our computational framework can aid both experimental and computational researchers toward effectively screening multimetallic NP stability. Moreover, we provide an outlook of how this framework can be applied to catalyst discovery, high-entropy alloys, and single-atom alloys.
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11
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Li S, Nagarajan AV, Du X, Li Y, Liu Z, Kauffman DR, Mpourmpakis G, Jin R. Dissecting Critical Factors for Electrochemical CO
2
Reduction on Atomically Precise Au Nanoclusters. Angew Chem Int Ed Engl 2022; 61:e202211771. [DOI: 10.1002/anie.202211771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Indexed: 11/16/2022]
Affiliation(s)
- Site Li
- Department of Chemistry Carnegie Mellon University Pittsburgh PA 15213 USA
- National Energy Technology Laboratory (NETL) United States Department of Energy Pittsburgh, PA USA
| | | | - Xiangsha Du
- Department of Chemistry Carnegie Mellon University Pittsburgh PA 15213 USA
| | - Yingwei Li
- Department of Chemistry Carnegie Mellon University Pittsburgh PA 15213 USA
| | - Zhongyu Liu
- Department of Chemistry Carnegie Mellon University Pittsburgh PA 15213 USA
| | - Douglas R. Kauffman
- National Energy Technology Laboratory (NETL) United States Department of Energy Pittsburgh, PA USA
| | - Giannis Mpourmpakis
- Department of Chemical Engineering University of Pittsburgh Pittsburgh PA 15261 USA
| | - Rongchao Jin
- Department of Chemistry Carnegie Mellon University Pittsburgh PA 15213 USA
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12
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Li S, Nagarajan AV, Du X, Li Y, Liu Z, Kauffman DR, Mpourmpakis G, Jin R. Dissecting Critical Factors for Electrochemical CO
2
Reduction on Atomically Precise Au Nanoclusters. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202211771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Site Li
- Department of Chemistry Carnegie Mellon University Pittsburgh PA 15213 USA
- National Energy Technology Laboratory (NETL) United States Department of Energy Pittsburgh, PA USA
| | | | - Xiangsha Du
- Department of Chemistry Carnegie Mellon University Pittsburgh PA 15213 USA
| | - Yingwei Li
- Department of Chemistry Carnegie Mellon University Pittsburgh PA 15213 USA
| | - Zhongyu Liu
- Department of Chemistry Carnegie Mellon University Pittsburgh PA 15213 USA
| | - Douglas R. Kauffman
- National Energy Technology Laboratory (NETL) United States Department of Energy Pittsburgh, PA USA
| | - Giannis Mpourmpakis
- Department of Chemical Engineering University of Pittsburgh Pittsburgh PA 15261 USA
| | - Rongchao Jin
- Department of Chemistry Carnegie Mellon University Pittsburgh PA 15213 USA
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13
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Mallette AJ, Hong S, Freeman EE, Saslow SA, Mergelsberg S, Motkuri RK, Neeway JJ, Mpourmpakis G, Rimer JD. Heteroatom Manipulation of Zeolite Crystallization: Stabilizing Zn-FAU against Interzeolite Transformation. JACS Au 2022; 2:2295-2306. [PMID: 36311839 PMCID: PMC9597603 DOI: 10.1021/jacsau.2c00325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 08/24/2022] [Accepted: 08/25/2022] [Indexed: 06/16/2023]
Abstract
The preparation of metastable zeolites is often restricted to a limited range of synthesis conditions, which is exemplified in commercial syntheses lacking organics to stabilize the crystal structure. In the absence of an organic structure-directing agent, interzeolite transformation is a common phenomenon that can lead to undesirable products or impurities. Many studies have investigated the substitution of Si and Al in zeolite frameworks with alternative elements (heteroatoms) as a means of tailoring the properties of zeolites; however, relatively few studies have systematically explored the impact of heteroatoms on interzeolite transformations and their concomitant effects on zeolite crystallization. In this study, we examine methods to prepare isostructures of faujasite (FAU), which is one of the most commercially relevant zeolites and also a thermodynamically metastable structure. A survey of multivalent elements revealed that zinc is capable of stabilizing FAU at high temperatures and inhibiting its frequent transformation to zeolite gismondine (GIS). Using combined experimental and computational studies, we show that zinc alters the chemical nature of growth mixtures by sequestering silicates. Zinc heteroatoms incorporate in the FAU framework with a loading-dependent coordination. Our collective findings provide an improved understanding of driving forces for the FAU-to-GIS interzeolite transformation where we observe that heteroatoms (e.g., zinc) can stabilize zeolite FAU over a broad range of synthesis conditions. Given the growing interest in heteroatom-substituted zeolites, this approach to preparing zinc-containing FAU may prove applicable to a broader range of zeolite structures.
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Affiliation(s)
- Adam J. Mallette
- Department
of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204, United States
| | - Sungil Hong
- Department
of Chemical and Petroleum Engineering, University
of Pittsburgh, Pittsburgh, Pennsylvania 15213, United States
| | - Emily E. Freeman
- Department
of Chemical and Petroleum Engineering, University
of Pittsburgh, Pittsburgh, Pennsylvania 15213, United States
| | - Sarah A. Saslow
- Pacific
Northwest National Laboratory, Richland, Washington 99354, United States
| | | | - Radha K. Motkuri
- Pacific
Northwest National Laboratory, Richland, Washington 99354, United States
| | - James J. Neeway
- Pacific
Northwest National Laboratory, Richland, Washington 99354, United States
| | - Giannis Mpourmpakis
- Department
of Chemical and Petroleum Engineering, University
of Pittsburgh, Pittsburgh, Pennsylvania 15213, United States
| | - Jeffrey D. Rimer
- Department
of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204, United States
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14
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Morales-Rivera CA, Cormack G, Burrington J, Proust N, Mpourmpakis G. Understanding and Optimizing the Behavior of Al- and Ru-Based Catalysts for the Synthesis of Polyisobutenyl Succinic Anhydrides. Ind Eng Chem Res 2022. [DOI: 10.1021/acs.iecr.2c02003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Cristian A. Morales-Rivera
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Glenn Cormack
- The Lubrizol Corporation, 29400 Lakeland Boulevard, Wickliffe, Ohio 44092, United States
| | - James Burrington
- The Lubrizol Corporation, 29400 Lakeland Boulevard, Wickliffe, Ohio 44092, United States
| | - Nicolas Proust
- The Lubrizol Corporation, 29400 Lakeland Boulevard, Wickliffe, Ohio 44092, United States
| | - Giannis Mpourmpakis
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
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15
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Ding R, Padilla Espinosa IM, Loevlie D, Azadehranjbar S, Baker AJ, Mpourmpakis G, Martini A, Jacobs TDB. Size-dependent shape distributions of platinum nanoparticles. Nanoscale Adv 2022; 4:3978-3986. [PMID: 36133342 PMCID: PMC9470057 DOI: 10.1039/d2na00326k] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 08/18/2022] [Indexed: 06/16/2023]
Abstract
While it is well established that nanoparticle shape can depend on equilibrium thermodynamics or growth kinetics, recent computational work has suggested the importance of thermal energy in controlling the distribution of shapes in populations of nanoparticles. Here, we used transmission electron microscopy to characterize the shapes of bare platinum nanoparticles and observed a strong dependence of shape distribution on particle size. Specifically, the smallest nanoparticles (<2.5 nm) had a truncated octahedral shape, bound by 〈111〉 and 〈100〉 facets, as predicted by lowest-energy thermodynamics. However, as particle size increased, the higher-energy 〈110〉 facets became increasingly common, leading to a large population of non-equilibrium truncated cuboctahedra. The observed trends were explained by combining atomistic simulations (both molecular dynamics and an empirical square-root bond-cutting model) with Boltzmann statistics. Overall, this study demonstrates experimentally how thermal energy leads to shape variation in populations of metal nanoparticles, and reveals the dependence of shape distributions on particle size. The prevalence of non-equilibrium facets has implications for metal nanoparticles applications from catalysis to solar energy.
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Affiliation(s)
- Ruikang Ding
- Department of Mechanical Engineering and Materials Science, University of Pittsburgh Pittsburgh PA 15261 USA
| | | | - Dennis Loevlie
- Department of Chemical and Petroleum Engineering, University of Pittsburgh Pittsburgh PA 15261 USA
| | - Soodabeh Azadehranjbar
- Department of Mechanical Engineering and Materials Science, University of Pittsburgh Pittsburgh PA 15261 USA
| | - Andrew J Baker
- Department of Mechanical Engineering and Materials Science, University of Pittsburgh Pittsburgh PA 15261 USA
| | - Giannis Mpourmpakis
- Department of Chemical and Petroleum Engineering, University of Pittsburgh Pittsburgh PA 15261 USA
| | - Ashlie Martini
- Department of Mechanical Engineering, University of California, Merced Merced CA 95343 USA
| | - Tevis D B Jacobs
- Department of Mechanical Engineering and Materials Science, University of Pittsburgh Pittsburgh PA 15261 USA
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16
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Choudhary N, Abdelgaid M, Mpourmpakis G, Mobin SM. CuNi bimetallic nanocatalyst enables sustainable direct carboxylation reactions. Molecular Catalysis 2022. [DOI: 10.1016/j.mcat.2022.112620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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17
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Nagarajan AV, Loevlie DJ, Cowan MJ, Mpourmpakis G. Resolving electrocatalytic imprecision in atomically precise metal nanoclusters. Curr Opin Chem Eng 2022. [DOI: 10.1016/j.coche.2021.100784] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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18
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Miu EV, McKone JR, Mpourmpakis G. The Sensitivity of Metal Oxide Electrocatalysis to Bulk Hydrogen Intercalation: Hydrogen Evolution on Tungsten Oxide. J Am Chem Soc 2022; 144:6420-6433. [PMID: 35289172 DOI: 10.1021/jacs.2c00825] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Metal oxides are attracting increased attention as electrocatalysts owing to their affordability, tunability, and reactivity. However, these materials can undergo significant chemical changes under reaction conditions, presenting challenges for characterization and optimization. Herein, we combine experimental and computational methods to demonstrate that bulk hydrogen intercalation governs the activity of tungsten trioxide (WO3) toward the hydrogen evolution reaction (HER). In contrast to the focus on surface processes in heterogeneous catalysis, we demonstrate that bulk oxide modification is responsible for experimental HER activity. Density functional theory (DFT) calculations reveal that intercalation enables the HER by altering the acid-base character of surface sites and preventing site blocking by hydration. First-principles microkinetic modeling supports that the experimental HER rates can only be explained by intercalated HxWO3, whereas nonintercalated WO3 does not catalyze the HER. Overall, this work underscores the critical influence of hydrogen intercalation on aqueous cathodic electrocatalysis at metal oxides.
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Affiliation(s)
- Evan V Miu
- Department of Chemical & Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, United States
| | - James R McKone
- Department of Chemical & Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, United States
| | - Giannis Mpourmpakis
- Department of Chemical & Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, United States
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19
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Affiliation(s)
- Mona Abdelgaid
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Giannis Mpourmpakis
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
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20
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Salem M, Cowan MJ, Mpourmpakis G. Predicting Segregation Energy in Single Atom Alloys Using Physics and Machine Learning. ACS Omega 2022; 7:4471-4481. [PMID: 35155939 PMCID: PMC8830057 DOI: 10.1021/acsomega.1c06337] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 01/11/2022] [Indexed: 06/14/2023]
Abstract
Single atom alloys (SAAs) show great promise as catalysts for a wide variety of reactions due to their tunable properties, which can enhance the catalytic activity and selectivity. To design SAAs, it is imperative for the heterometal dopant to be stable on the surface as an active catalytic site. One main approach to probe SAA stability is to calculate surface segregation energy. Density functional theory (DFT) can be applied to investigate the surface segregation energy in SAAs. However, DFT is computationally expensive and time-consuming; hence, there is a need for accelerated frameworks to screen metal segregation for new SAA catalysts across combinations of metal hosts and dopants. To this end, we developed a model that predicts surface segregation energy using machine learning for a series of SAA periodic slabs. The model leverages elemental descriptors and features inspired by the previously developed bond-centric model. The initial model accurately captures surface segregation energy across a diverse series of FCC-based SAAs with various surface facets and metal-host pairs. Following our machine learning methodology, we expanded our analysis to develop a new model for SAAs formed from FCC hosts with FCC, BCC, and HCP dopants. Our final, five-feature model utilizes second-order polynomial kernel ridge regression. The model is able to predict segregation energies with a high degree of accuracy, which is due to its physically motivated features. We then expanded our data set to test the accuracy of the five features used. We find that the retrained model can accurately capture E seg trends across different metal hosts and facets, confirming the significance of the features used in our final model. Finally, we apply our pretrained model to a series of Ir- and Pd-based SAA cuboctahedron nanoparticles (NPs), ranging in size and FCC dopants. Remarkably, our model (trained on periodic slabs) accurately predicts the DFT segregation energies of the SAA NPs. The results provide further evidence supporting the use of our model as a general tool for the rapid prediction of SAA segregation energies. By creating a framework to predict the metal segregation from bulk surfaces to NPs, we can accelerate the SAA catalyst design while simultaneously unraveling key physicochemical properties driving thermodynamic stabilization of SAAs.
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21
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Sleight TW, Sexton CN, Mpourmpakis G, Gilbertson LM, Ng CA. A Classification Model to Identify Direct-Acting Mutagenic Polycyclic Aromatic Hydrocarbon Transformation Products. Chem Res Toxicol 2021; 34:2273-2286. [PMID: 34662518 DOI: 10.1021/acs.chemrestox.1c00187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Polycyclic aromatic hydrocarbons (PAHs) are a complex group of environmental contaminants, many having long environmental half-lives. As these compounds degrade, the changes in their structure can result in a substantial increase in mutagenicity compared to the parent compound. Over time, each individual PAH can potentially degrade into several thousand unique transformation products, creating a complex, constantly evolving set of intermediates. Microbial degradation is the primary mechanism of their transformation and ultimate removal from the environment, and this process can result in mutagenic activation similar to the metabolic activation that can occur in multicellular organisms. The diversity of the potential intermediate structures in PAH-contaminated environments renders hazard assessment difficult for both remediation professionals and regulators. A mixture of structural and energetic descriptors has proven effective in existing studies for classifying which PAH transformation products will be mutagenic. However, most existing studies of environmental PAH mutagens primarily focus on nitrogenated derivatives, which are prevalent in the atmosphere and not as relevant in soil. Additionally, PAH products commonly found in the environment can range from as large as five rings to as small as a single ring, requiring a broadly inclusive methodology to comprehensively evaluate mutagenic potential. We developed a combination of supervised and unsupervised machine learning methods to predict environmentally induced PAH mutagenicity with improved performance over currently available tools. K-means clustering with principal component analysis allows us to identify molecular clusters that we hypothesize to have similar mechanisms of action. Recursive feature elimination identifies the most influential descriptors. The cluster-specific regression outperforms available classifiers in predicting direct-acting mutagens resulting from the microbial biodegradation of PAHs and provides direction for future studies evaluating the environmental hazards resulting from PAH biodegradation.
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Affiliation(s)
- Trevor W Sleight
- Civil & Environmental Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Caitlin N Sexton
- Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Giannis Mpourmpakis
- Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Leanne M Gilbertson
- Civil & Environmental Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States.,Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Carla A Ng
- Civil & Environmental Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States.,Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
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22
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Abstract
CuZrO3 has been hypothesized to be a catalytic material with potential applications for CO2 reduction. Unfortunately, this material has received limited attention in the literature, and to the best of our knowledge the exact crystal structure is still unknown. To address this challenge, we utilize several different structural prediction techniques in concert, including the Universal Structure Predictor: Evolutionary Xtallography (USPEX), the Materials Project Structure Predictor, and the Open Quantum Materials Database (OQMD). Leveraging these structural prediction techniques in conjunction with Density-Functional Theory (DFT) calculations, we determine a possible structure for CuZrO3, which resembles a "sandwich" morphology. Our calculations reveal that this new structure is significantly lower in energy than a previously hypothesized perovskite structure, albeit it still has a thermodynamic preference to decompose into CuO and ZrO2. In addition, we experimentally tried to synthesize CuZrO3 based on literature reports and compared computational to experimental X-ray Diffraction (XRD) patterns confirming that the final product is a mixture of CuO and ZrO2. Finally, we conducted a computational surface energetics and CO2 adsorption study on our discovered sandwich morphology, demonstrating that CO2 can adsorb and activate on the material. However, these CO2 adsorption results deviate from previously reported results further confirming that the CuZrO3 is a metastable form and may not be experimentally accessible as a well-mixed oxide, since phase segregation to CuO and ZrO2 is preferred. Taken together, our combined computational and experimental study provides evidence that the synthesis of CuZrO3 is extremely difficult and if this oxide exists, it should have a sandwich-like morphology.
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Affiliation(s)
- James Dean
- Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, PA 15213, USA.
| | - Yahui Yang
- Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, PA 15213, USA.
| | - Götz Veser
- Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, PA 15213, USA.
| | - Giannis Mpourmpakis
- Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, PA 15213, USA.
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23
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Li Y, Li S, Nagarajan AV, Liu Z, Nevins S, Song Y, Mpourmpakis G, Jin R. Hydrogen Evolution Electrocatalyst Design: Turning Inert Gold into Active Catalyst by Atomically Precise Nanochemistry. J Am Chem Soc 2021; 143:11102-11108. [PMID: 34270239 DOI: 10.1021/jacs.1c04606] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Electrocatalytic hydrogen evolution reaction (HER) holds promise in the renewable clean energy scheme. Crystalline Au and Ag are, however, poor in catalyzing HER, and the ligands on colloidal nanoparticles are generally another disadvantage. Herein, we report a thiolate (SR)-protected Au36Ag2(SR)18 nanocluster with low coverage of ligands and a core composed of three icosahedral (Ih) units for catalyzing HER efficiently. This trimeric structure, together with the monomeric Ih Au25(SR)18- and dimeric Ih Au38(SR)24, constitutes a unique series, providing an opportunity for revealing the correlation between the catalytic properties and the catalyst's structure. The Au36Ag2(SR)18 surprisingly exhibits high catalytic activity at lower overpotentials for HER due to its low ligand-to-metal ratio, low-coordinated Au atoms and unfilled superatomic orbitals. The current density of Au36Ag2(SR)18 at -0.3 V vs RHE is 3.8 and 5.1 times that of Au25(SR)18- and Au38(SR)24, respectively. Density functional theory (DFT) calculations reveal lower hydrogen binding energy and higher electron affinity of Au36Ag2(SR)18 for an energetically feasible HER pathway. Our findings provide a new strategy for constructing highly active catalysts from inert metals by pursuing atomically precise nanoclusters and controlling their geometrical and electronic structures.
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Affiliation(s)
- Yingwei Li
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Site Li
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Anantha V Nagarajan
- Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Zhongyu Liu
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Sarah Nevins
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Yongbo Song
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States.,School of Biomedical Engineering, Research and Engineering Center of Biomedical Materials, Anhui Medical University, Hefei, Anhui 230032, China
| | - Giannis Mpourmpakis
- Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Rongchao Jin
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
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24
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Cowan MJ, Nagarajan AV, Mpourmpakis G. Correlating structural rules with electronic properties of ligand-protected alloy nanoclusters. J Chem Phys 2021; 155:024303. [PMID: 34266280 DOI: 10.1063/5.0056690] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Thiolate protected gold nanoclusters (TPNCs) are a unique class of nanomaterials finding applications in various fields, such as biomedicine, optics, and catalysis. The atomic precision of their structure, characterized through single crystal x-ray diffraction, enables the accurate investigation of their physicochemical properties through electronic structure calculations. Recent experimental efforts have led to the successful heterometal doping of TPNCs, potentially unlocking a large domain of bimetallic TPNCs for targeted applications. However, how TPNC size, bimetallic composition, and location of dopants influence electronic structure is unknown. To this end, we introduce novel structure-property relationships (SPRs) that predict electronic properties such as ionization potential (IP) and electron affinity (EA) of AgAu TPNCs based on physically relevant descriptors. The models are constructed by first generating a hypothetical AgAu TPNC dataset of 368 structures with sizes varying from 36 to 279 metal atoms. Using our dataset calculated with density functional theory (DFT), we employed systematic analyses to unravel size, composition, and, importantly, core-shell effects on TPNC EA and IP behavior. We develop generalized SPRs that are able to predict electronic properties across the AgAu TPNC materials space. The models leverage the same three fundamental descriptors (i.e., size, composition, and core-shell makeup) that do not require DFT calculations and rely only on simple atom counting, opening avenues for high throughput bimetallic TPNC screening for targeted applications. This work is a first step toward finely controlling TPNC electronic properties through heterometal doping using high throughput computational means.
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Affiliation(s)
- Michael J Cowan
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15216, USA
| | | | - Giannis Mpourmpakis
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15216, USA
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25
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Li S, Nagarajan AV, Alfonso DR, Sun M, Kauffman DR, Mpourmpakis G, Jin R. Boosting CO
2
Electrochemical Reduction with Atomically Precise Surface Modification on Gold Nanoclusters. Angew Chem Int Ed Engl 2021; 60:6351-6356. [DOI: 10.1002/anie.202016129] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Indexed: 12/22/2022]
Affiliation(s)
- Site Li
- Department of Chemistry Carnegie Mellon University Pittsburgh PA 15213 USA
- National Energy Technology Laboratory (NETL) United States Department of Energy Pittsburgh PA USA
| | | | - Dominic R. Alfonso
- National Energy Technology Laboratory (NETL) United States Department of Energy Pittsburgh PA USA
| | - Mingkang Sun
- Department of Chemistry Carnegie Mellon University Pittsburgh PA 15213 USA
| | - Douglas R. Kauffman
- National Energy Technology Laboratory (NETL) United States Department of Energy Pittsburgh PA USA
| | - Giannis Mpourmpakis
- Department of Chemical Engineering University of Pittsburgh Pittsburgh PA 15261 USA
| | - Rongchao Jin
- Department of Chemistry Carnegie Mellon University Pittsburgh PA 15213 USA
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26
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Li S, Nagarajan AV, Alfonso DR, Sun M, Kauffman DR, Mpourmpakis G, Jin R. Boosting CO
2
Electrochemical Reduction with Atomically Precise Surface Modification on Gold Nanoclusters. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202016129] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Site Li
- Department of Chemistry Carnegie Mellon University Pittsburgh PA 15213 USA
- National Energy Technology Laboratory (NETL) United States Department of Energy Pittsburgh PA USA
| | | | - Dominic R. Alfonso
- National Energy Technology Laboratory (NETL) United States Department of Energy Pittsburgh PA USA
| | - Mingkang Sun
- Department of Chemistry Carnegie Mellon University Pittsburgh PA 15213 USA
| | - Douglas R. Kauffman
- National Energy Technology Laboratory (NETL) United States Department of Energy Pittsburgh PA USA
| | - Giannis Mpourmpakis
- Department of Chemical Engineering University of Pittsburgh Pittsburgh PA 15261 USA
| | - Rongchao Jin
- Department of Chemistry Carnegie Mellon University Pittsburgh PA 15213 USA
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27
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Li S, Nagarajan AV, Li Y, Kauffman DR, Mpourmpakis G, Jin R. The role of ligands in atomically precise nanocluster-catalyzed CO 2 electrochemical reduction. Nanoscale 2021; 13:2333-2337. [PMID: 33464267 DOI: 10.1039/d0nr07832h] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Ligand effects are of major interest in catalytic reactions owing to their potential critical role in determining the reaction activity and selectivity. Herein, we report ligand effects in the CO2 electrochemical reduction reaction at the atomic level with three unique Au25 nanoclusters comprising the same kernel but different protecting ligands (-XR, where X = S or Se, and R represents the carbon tail). It is observed that a change in the carbon tail shows no obvious impact on the catalytic selectivity and activity, but the anchoring atom (X = S or Se) strongly affects the electrocatalytic selectivity. Specifically, the S site acts as the active site and sustains CO selectivity, while the Se site shows a higher tendency of hydrogen evolution. Density functional theory (DFT) calculations reveal that the energy penalty associated with the *COOH formation is lower on the S site by 0.26 eV compared to that on the Se site. Additionally, the formation energy of the product (*CO) is lower on the sulfur-based Au nanocluster by 0.43 eV. We attribute these energetic differences to the higher electron density on the sulfur sites of the Au nanocluster, resulting in a modified bonding character of the reaction intermediates that reduce the energetic penalty for the *COOH and *CO formation. Overall, this work demonstrates that S/Se atoms at the metal-ligand interface can play an important role in determining the overall electrocatalytic performance of Au nanoclusters.
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Affiliation(s)
- Site Li
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA. and National Energy Technology Laboratory (NETL), United States Department of Energy, Pittsburgh, Pennsylvania, USA.
| | | | - Yingwei Li
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA.
| | - Douglas R Kauffman
- National Energy Technology Laboratory (NETL), United States Department of Energy, Pittsburgh, Pennsylvania, USA.
| | - Giannis Mpourmpakis
- Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA.
| | - Rongchao Jin
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA.
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28
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McKay J, Cowan MJ, Morales-Rivera CA, Mpourmpakis G. Predicting ligand removal energetics in thiolate-protected nanoclusters from molecular complexes. Nanoscale 2021; 13:2034-2043. [PMID: 33449990 DOI: 10.1039/d0nr07839e] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Thiolate-protected metal nanoclusters (TPNCs) have attracted great interest in the last few decades due to their high stability, atomically precise structure, and compelling physicochemical properties. Among their various applications, TPNCs exhibit excellent catalytic activity for numerous reactions; however, recent work revealed that these systems must undergo partial ligand removal in order to generate active sites. Despite the importance of ligand removal in both catalysis and stability of TPNCs, the role of ligands and metal type in the process is not well understood. Herein, we utilize Density Functional Theory to understand the energetic interplay between metal-sulfur and sulfur-ligand bond dissociation in metal-thiolate systems. We first probe 66 metal-thiolate molecular complexes across combinations of M = Ag, Au, and Cu with twenty-two different ligands (R). Our results reveal that the energetics to break the metal-sulfur and sulfur-ligand bonds are strongly correlated and can be connected across all complexes through metal atomic ionization potentials. We then extend our work to the experimentally relevant [M25(SR)18]- TPNC, revealing the same correlations at the nanocluster level. Importantly, we unify our work by introducing a simple methodology to predict TPNC ligand removal energetics solely from calculations performed on metal-ligand molecular complexes. Finally, a computational mechanistic study was performed to investigate the hydrogenation pathways for SCH3-based complexes. The energy barriers for these systems revealed, in addition to thermodynamics, that kinetics favor the break of S-R over the M-S bond in the case of the Au complex. Our computational results rationalize several experimental observations pertinent to ligand effects on TPNCs. Overall, our introduced model provides an accelerated path to predict TPNC ligand removal energies, thus aiding towards targeted design of TPNC catalysts.
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Affiliation(s)
- Julia McKay
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA 15261, USA.
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29
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Morales-Rivera CA, Proust N, Burrington J, Mpourmpakis G. Computational Screening of Lewis Acid Catalysts for the Ene Reaction between Maleic Anhydride and Polyisobutylene. Ind Eng Chem Res 2021. [DOI: 10.1021/acs.iecr.0c04860] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Cristian A. Morales-Rivera
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Nico Proust
- The Lubrizol Corporation, 29400 Lakeland Blvd, Wickliffe, Ohio 44092, United States
| | - James Burrington
- The Lubrizol Corporation, 29400 Lakeland Blvd, Wickliffe, Ohio 44092, United States
| | - Giannis Mpourmpakis
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
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30
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Li W, Taylor MG, Bayerl D, Mozaffari S, Dixit M, Ivanov S, Seifert S, Lee B, Shanaiah N, Lu Y, Kovarik L, Mpourmpakis G, Karim AM. Solvent manipulation of the pre-reduction metal-ligand complex and particle-ligand binding for controlled synthesis of Pd nanoparticles. Nanoscale 2021; 13:206-217. [PMID: 33325939 DOI: 10.1039/d0nr06078j] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Understanding how to control the nucleation and growth rates is crucial for designing nanoparticles with specific sizes and shapes. In this study, we show that the nucleation and growth rates are correlated with the thermodynamics of metal-ligand/solvent binding for the pre-reduction complex and the surface of the nanoparticle, respectively. To obtain these correlations, we measured the nucleation and growth rates by in situ small angle X-ray scattering during the synthesis of colloidal Pd nanoparticles in the presence of trioctylphosphine in solvents of varying coordinating ability. The results show that the nucleation rate decreased, while the growth rate increased in the following order, toluene, piperidine, 3,4-lutidine and pyridine, leading to a large increase in the final nanoparticle size (from 1.4 nm in toluene to 5.0 nm in pyridine). Using density functional theory (DFT), complemented by 31P nuclear magnetic resonance and X-ray absorption spectroscopy, we calculated the reduction Gibbs free energies of the solvent-dependent dominant pre-reduction complex and the solvent-nanoparticle binding energy. The results indicate that lower nucleation rates originate from solvent coordination which stabilizes the pre-reduction complex and increases its reduction free energy. At the same time, DFT calculations suggest that the solvent coordination affects the effective capping of the surface where stronger binding solvents slow the nanoparticle growth by lowering the number of active sites (not already bound by trioctylphosphine). The findings represent a promising advancement towards understanding the microscopic connection between the metal-ligand thermodynamic interactions and the kinetics of nucleation and growth to control the size of colloidal metal nanoparticles.
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Affiliation(s)
- Wenhui Li
- Department of Chemical Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060, USA.
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31
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Abstract
DFT calculations and kinetic modeling elucidate solvent effects and complex mechanisms for the room-temperature methane-to-methanol conversion on an FeN4/graphene catalyst.
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Affiliation(s)
- Sungil Hong
- Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA
| | - Giannis Mpourmpakis
- Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA
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32
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Li Y, Cowan MJ, Zhou M, Luo TY, Song Y, Wang H, Rosi NL, Mpourmpakis G, Jin R. Atom-by-Atom Evolution of the Same Ligand-Protected Au 21, Au 22, Au 22Cd 1, and Au 24 Nanocluster Series. J Am Chem Soc 2020; 142:20426-20433. [PMID: 33170677 DOI: 10.1021/jacs.0c09110] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Atom-by-atom manipulation on metal nanoclusters (NCs) has long been desired, as the resulting series of NCs can provide insightful understanding of how a single atom affects the structure and properties as well as the evolution with size. Here, we report crystallizations of Au22(SAdm)16 and Au22Cd1(SAdm)16 (SAdm = adamantanethiolate) which link up with Au21(SAdm)15 and Au24(SAdm)16 NCs and form an atom-by-atom evolving series protected by the same ligand. Structurally, Au22(SAdm)16 has an Au3(SAdm)4 surface motif which is longer than the Au2(SAdm)3 on Au21(SAdm)15, whereas Au22Cd1(SAdm)16 lacks one staple Au atom compared to Au24(SAdm)16 and thus the surface structure is reconstructed. A single Cd atom triggers the structural transition from Au22 with a 10-atom bioctahedral kernel to Au22Cd1 with a 13-atom cuboctahedral kernel, and correspondingly, the optical properties are dramatically changed. The photoexcited carrier lifetime demonstrates that the optical properties and excited state relaxation are highly sensitive at the single atom level. By contrast, little change in both ionization potential and electron affinity is found in this series of NCs by theoretical calculations, indicating the electronic properties are independent of adding a single atom in this series. The work provides a paradigm that the NCs with continuous metal atom numbers are accessible and crystallizable when meticulously designed, and the optical properties are more affected at the single atom level than the electronic properties.
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Affiliation(s)
- Yingwei Li
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Michael J Cowan
- Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Meng Zhou
- Department of Physics, University of Miami, Coral Gables, Florida 33146, United States
| | - Tian-Yi Luo
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Yongbo Song
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - He Wang
- Department of Physics, University of Miami, Coral Gables, Florida 33146, United States
| | - Nathaniel L Rosi
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Giannis Mpourmpakis
- Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Rongchao Jin
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
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33
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Freeman EE, Neeway JJ, Motkuri RK, Rimer JD, Mpourmpakis G. Understanding initial zeolite oligomerization steps with first principles calculations. AIChE J 2020. [DOI: 10.1002/aic.17107] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Emily E. Freeman
- Department of Chemical and Petroleum Engineering University of Pittsburgh Pittsburgh Pennsylvania USA
| | - James J. Neeway
- Energy and Environment Directorate Pacific Northwest National Laboratory Richland Washington USA
| | - Radha Kishan Motkuri
- Energy and Environment Directorate Pacific Northwest National Laboratory Richland Washington USA
| | - Jeffrey D. Rimer
- Department of Chemical and Biomolecular Engineering University of Houston Houston Texas USA
| | - Giannis Mpourmpakis
- Department of Chemical and Petroleum Engineering University of Pittsburgh Pittsburgh Pennsylvania USA
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34
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Miu EV, Mpourmpakis G, McKone JR. Predicting the Energetics of Hydrogen Intercalation in Metal Oxides Using Acid-Base Properties. ACS Appl Mater Interfaces 2020; 12:44658-44670. [PMID: 32929950 DOI: 10.1021/acsami.0c11300] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The ability to predict intercalation energetics from first principles is attractive for identifying candidate materials for energy storage, chemical sensing, and catalysis. In this work, we introduce a computational framework that can be used to predict the thermodynamics of hydrogen intercalation in tungsten trioxide (WO3). Specifically, using density functional theory (DFT), we investigated intercalation energetics as a function of adsorption site and hydrogen stoichiometry. Site-specific acid-base properties determined using DFT were used to develop linear structure screening models that informed a kernel ridge energy prediction model. These regressions provided a series of hydrogen binding energy predictions across stoichiometries ranging from WO3 to H0.625WO3, which were then converted to equilibrium potentials for hydrogen intercalation. Experimental validation using cyclic voltammetry measurements yielded good agreement with the predicted intercalation potentials. This methodology enables fast exploration of a large geometric configuration space and reveals an intuitive physical relationship between acidity, basicity, and the thermodynamics of hydrogen intercalation. Furthermore, the combination of theoretical and experimental results suggests H0.500WO3 as a maximum stable stoichiometry for the bronzes that arises from competition with hydrogen evolution rather than the inability of WO3 to accommodate additional hydrogen. Our experimental results further indicate hydrogen insertion in WO3 is highly irreversible for low H-stoichiometries, which we propose to be a consequence of the semiconductor-to-metal transition that occurs upon initial H-intercalation. Overall, the agreement between theory and experiment suggests that local acid-base characteristics govern hydrogen intercalation in tungsten trioxide, and this insight can aid the accelerated discovery of redox-active metal oxides for catalytic hydrogenations.
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Affiliation(s)
- Evan V Miu
- Department of Chemical & Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Giannis Mpourmpakis
- Department of Chemical & Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - James R McKone
- Department of Chemical & Petroleum Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
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35
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Li S, Alfonso D, Nagarajan AV, House SD, Yang JC, Kauffman DR, Mpourmpakis G, Jin R. Monopalladium Substitution in Gold Nanoclusters Enhances CO2 Electroreduction Activity and Selectivity. ACS Catal 2020. [DOI: 10.1021/acscatal.0c02266] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Site Li
- Department of Chemistry, Carnegie Mellon University, Pittsburgh 15213, Pennsylvania, United States
- United States Department of Energy, National Energy Technology Laboratory (NETL), Pittsburgh 15236, Pennsylvania, United States
| | - Dominic Alfonso
- United States Department of Energy, National Energy Technology Laboratory (NETL), Pittsburgh 15236, Pennsylvania, United States
| | | | - Stephen D. House
- Chemical and Petroleum Engineering, and Physics, University of Pittsburgh, Pittsburgh 15261, Pennsylvania, United States
| | - Judith C. Yang
- Chemical and Petroleum Engineering, and Physics, University of Pittsburgh, Pittsburgh 15261, Pennsylvania, United States
| | - Douglas R. Kauffman
- United States Department of Energy, National Energy Technology Laboratory (NETL), Pittsburgh 15236, Pennsylvania, United States
| | - Giannis Mpourmpakis
- Department of Chemical Engineering, University of Pittsburgh, Pittsburgh 15261, Pennsylvania, United States
| | - Rongchao Jin
- Department of Chemistry, Carnegie Mellon University, Pittsburgh 15213, Pennsylvania, United States
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36
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Li Y, Taylor MG, Luo TY, Song Y, Rosi NL, Mpourmpakis G, Jin R. Heteroatom Tracing Reveals the 30-Atom Au-Ag Bimetallic Nanocluster as a Dimeric Structure. J Phys Chem Lett 2020; 11:7307-7312. [PMID: 32787300 DOI: 10.1021/acs.jpclett.0c01977] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Understanding the formation of face-centered cubic (fcc) nanostructures at the atomic level remains a major task. With atomically precise nanoclusters (NCs) as model systems, herein we devised an atom-tracing strategy by heteroatom doping into Au30(SR)18 (SR = S-tC4H9) to label the specific positions in M30(SR)18 NCs (M = Au/Ag), which clearly reveals the dimeric nature of M30. Interestingly, the specific position is also consistent with the Ag-doping site in M21(SR)15. Electronic orbital analysis shows intrinsic orbital localization at the two specific positions in M30, which are decisive to the electronic structure of M30, regardless of Au or Ag occupancy. The fcc dimeric NC, which would not be discovered without Ag tracing, provides a possible explanation for the wide accessibility of nonsuperatomic Au-SR NCs.
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Affiliation(s)
- Yingwei Li
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Michael G Taylor
- Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Tian-Yi Luo
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Yongbo Song
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Nathaniel L Rosi
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Giannis Mpourmpakis
- Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Rongchao Jin
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
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37
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Abstract
The nanoparticle (NP) design space allows for variations in size, shape, composition, and chemical ordering. In the search for low-energy structures, this results in an extremely large search space which cannot be screened by brute force methods. In this work, we develop a genetic algorithm to predict stable bimetallic NPs of any size, shape, and metal composition. Our method predicts nanostructures in agreement with experimental trends and it captures the detailed chemical ordering of an experimental 23,196-atom FePt NP with nearly atom-by-atom accuracy. Our developed screening process is extremely fast, allowing us to generate and analyze a database of 5454 low-energy bimetallic NPs. By identifying thermodynamically stable NPs, we rationalize bimetallic mixing at the nanoscale and reveal metal-, size-, and temperature-dependent mixing behavior. Importantly, our method is applicable to any bimetallic NP size, bridging the materials gap in nanoscale simulations, and guides experimentation in the lab by elucidating stability, mixing, and detailed chemical ordering behavior of bimetallic NPs.
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Affiliation(s)
- James Dean
- Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Michael J Cowan
- Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Jonathan Estes
- Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Mahmoud Ramadan
- Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Giannis Mpourmpakis
- Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
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38
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Li Y, Cowan MJ, Zhou M, Taylor MG, Wang H, Song Y, Mpourmpakis G, Jin R. Heterometal-Doped M 23 (M = Au/Ag/Cd) Nanoclusters with Large Dipole Moments. ACS Nano 2020; 14:6599-6606. [PMID: 32286795 DOI: 10.1021/acsnano.0c01000] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Dipole moment (μ) is a critical parameter for molecules and nanomaterials as it affects many properties. In metal-thiolate (SR) nanoclusters (NCs), μ is commonly low (0-5 D) compared to quantum dots. Herein, we report a doping strategy to give giant dipoles (∼18 D) in M23 (M = Au/Ag/Cd) NCs, falling in the experimental trend for II-VI quantum dots. In M23 NCs, high μ is caused by the Cd-Br bond and the arrangement of heteroatoms along the C3 axis. Strong dipole-dipole interactions are observed in crystalline state, with energy exceeding 5 kJ/mol, directing a "head-to-tail" alignment of Au22-nAgnCd1(SR)15X (SR = adamantanethiolate) dipoles. The alignment can be controlled by μ via doping. The optical absorption peaks of M23 show solvent polarity-dependent shifts (∼25 meV) with negative solvatochromism. Detailed electronic structures of M23 are revealed by density functional theory and time-dependent DFT calculations. Overall, the doping strategy for obtaining large dipole moments demonstrates an atomic-level design of clusters with useful properties.
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Affiliation(s)
- Yingwei Li
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Michael J Cowan
- Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Meng Zhou
- Department of Physics, University of Miami, Coral Gables, Florida 33146, United States
| | - Michael G Taylor
- Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - He Wang
- Department of Physics, University of Miami, Coral Gables, Florida 33146, United States
| | - Yongbo Song
- Department of Chemistry and Centre for Atomic Engineering of Advanced Materials, Anhui Province Key Laboratory of Chemistry for Inorganic/Organic Hybrid Functionalized Materials, Anhui University, Hefei, Anhui 230601, People's Republic of China
| | - Giannis Mpourmpakis
- Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Rongchao Jin
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
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39
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Affiliation(s)
- Raffaele Cheula
- Laboratory of Catalysis and Catalytic Processes, Dipartimento di Energia, Politecnico di Milano, Via La Masa, 34, 20156 Milano, Italy
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, 4200 Fifth Avenue, Pittsburgh, Pennsylvania 15260, United States
| | - Matteo Maestri
- Laboratory of Catalysis and Catalytic Processes, Dipartimento di Energia, Politecnico di Milano, Via La Masa, 34, 20156 Milano, Italy
| | - Giannis Mpourmpakis
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, 4200 Fifth Avenue, Pittsburgh, Pennsylvania 15260, United States
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40
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Li Y, Juarez-Mosqueda R, Song Y, Zhang Y, Chai J, Mpourmpakis G, Jin R. Ligand exchange on Au 38(SR) 24: substituent site effects of aromatic thiols. Nanoscale 2020; 12:9423-9429. [PMID: 32323691 DOI: 10.1039/d0nr01430c] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Understanding the critical roles of ligands (e.g. thiolates, SR) in the formation of metal nanoclusters of specific sizes has long been an intriguing task since the report of ligand exchange-induced transformation of Au38(SR)24 into Au36(SR')24. Herein, we conduct a systematic study of ligand exchange on Au38(SC2H4Ph)24 with 21 incoming thiols and reveal that the size/structure preference is dependent on the substituent site. Specifically, ortho-substituted benzenethiols preserve the structure of Au38(SR)24, while para- or non-substituted benzenethiols cause its transformation into Au36(SR)24. Strong electron-donating or -withdrawing groups do not make a difference, but they will inhibit full ligand exchange. Moreover, the crystal structure of Au38(SR)24 (SR = 2,4-dimethylbenzenethiolate) exhibits distinctive ππ stacking and "anagostic" interactions (indicated by substantially short AuH distances). Theoretical calculations reveal the increased energies of frontier orbitals for aromatic ligand-protected Au38, indicating decreased electronic stability. However, this adverse effect could be compensated for by the AuH-C interactions, which improve the geometric stability when ortho-substituted benzenethiols are used. Overall, this work reveals the substituent site effects based on the Au38 model, and highlights the long-neglected "anagostic" interactions on the surface of Au-SR NCs which improve the structural stability.
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Affiliation(s)
- Yingwei Li
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA.
| | - Rosalba Juarez-Mosqueda
- Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA.
| | - Yongbo Song
- Department of Chemistry and Centre for Atomic Engineering of Advanced Materials, Anhui Province Key Laboratory of Chemistry for Inorganic/Organic Hybrid Functionalized Materials, Anhui University, Hefei, Anhui 230601, People's Republic of China
| | - Yuzhuo Zhang
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA.
| | - Jinsong Chai
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA.
| | - Giannis Mpourmpakis
- Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA.
| | - Rongchao Jin
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA.
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41
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Abstract
Doping the surface of γ-Al2O3 with gallium enhances the alkane dehydrogenation catalytic activity.
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Affiliation(s)
- Mona Abdelgaid
- Department of Chemical Engineering
- University of Pittsburgh
- Pittsburgh
- USA
| | - James Dean
- Department of Chemical Engineering
- University of Pittsburgh
- Pittsburgh
- USA
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42
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Abstract
Developing a centralized database for ligand-protected nanoclusters can fuel machine learning and data-science-based approaches towards theoretical structure prediction.
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Affiliation(s)
- Michael J. Cowan
- Department of Chemical and Petroleum Engineering
- University of Pittsburgh
- Pittsburgh
- USA
| | - Giannis Mpourmpakis
- Department of Chemical and Petroleum Engineering
- University of Pittsburgh
- Pittsburgh
- USA
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43
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Mozaffari S, Li W, Dixit M, Seifert S, Lee B, Kovarik L, Mpourmpakis G, Karim AM. The role of nanoparticle size and ligand coverage in size focusing of colloidal metal nanoparticles. Nanoscale Adv 2019; 1:4052-4066. [PMID: 36132098 PMCID: PMC9417622 DOI: 10.1039/c9na00348g] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Accepted: 09/05/2019] [Indexed: 05/10/2023]
Abstract
Controlling the size distribution of nanoparticles is important for many applications and typically involves the use of ligands during synthesis. In this study, we show that the mechanism of size focusing involves a dependence of the growth rate on the size of the nanoparticles and the ligand coverage on the surface of the nanoparticles. To demonstrate these effects, we used in situ small angle X-ray scattering (SAXS) and population balance kinetic modeling (PBM) to investigate the evolution of size distribution during the synthesis of colloidal Pd metal nanoparticles. Despite temporal overlap of nucleation and growth, our in situ SAXS show size focusing of the distribution under different synthetic conditions (different concentrations of metal and ligand as well as solvent type). To understand the mechanism of size focusing using PBM, we systematically studied how the evolution of the nanoparticle size distribution is affected by nucleation rate, and dependence of the growth rate constant on ligand surface coverage, and size of the nanoparticles. We show that continuous nucleation contributes to size defocusing. However, continuous nucleation results in different reaction times for the nanoparticle population leading to time and size-dependent ligand surface coverage. Using density functional theory (DFT) calculations and Brønsted-Evans-Polanyi relations, we show that as the population grows, larger nanoparticles grow more slowly than smaller ones due to lower intrinsic activity and higher ligand coverage on the surface. Therefore, despite continuous nucleation, the faster growth of smaller nanoparticles in the population leads to size focusing. The size focusing behaviour (due to faster growth of smaller nanoparticles) was found to be model independent and similar results were demonstrated under different nucleation and growth pathways (e.g. growth via ion reduction on the surface and/or monomer addition). Our results provide a microscopic connection between kinetics and thermodynamics of nanoparticle growth and metal-ligand binding, and their effect on the size distribution of colloidal nanoparticles.
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Affiliation(s)
- Saeed Mozaffari
- Department of Chemical Engineering, Virginia Polytechnic Institute and State University Blacksburg VA 24060 USA
| | - Wenhui Li
- Department of Chemical Engineering, Virginia Polytechnic Institute and State University Blacksburg VA 24060 USA
| | - Mudit Dixit
- Department of Chemical Engineering, University of Pittsburgh Pittsburgh Pennsylvania 15261 USA
| | - Soenke Seifert
- Advanced Photon Source, Argonne National Laboratory Argonne IL 60439 USA
| | - Byeongdu Lee
- X-ray Science Division, Argonne National Laboratory Argonne IL 60439 USA
| | - Libor Kovarik
- Environmental Molecular Science Laboratory, Pacific Northwest National Laboratory Richland Washington 99352 USA
| | - Giannis Mpourmpakis
- Department of Chemical Engineering, University of Pittsburgh Pittsburgh Pennsylvania 15261 USA
| | - Ayman M Karim
- Department of Chemical Engineering, Virginia Polytechnic Institute and State University Blacksburg VA 24060 USA
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44
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Affiliation(s)
- Kaiyang Tan
- Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Mudit Dixit
- Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - James Dean
- Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Giannis Mpourmpakis
- Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
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45
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Dean J, Taylor MG, Mpourmpakis G. Unfolding adsorption on metal nanoparticles: Connecting stability with catalysis. Sci Adv 2019; 5:eaax5101. [PMID: 31548989 PMCID: PMC6744265 DOI: 10.1126/sciadv.aax5101] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 08/12/2019] [Indexed: 05/25/2023]
Abstract
Metal nanoparticles have received substantial attention in the past decades for their applications in numerous areas, including medicine, catalysis, energy, and the environment. Despite these applications, the fundamentals of adsorption on nanoparticle surfaces as a function of nanoparticle size, shape, metal composition, and type of adsorbate are yet to be found. Herein, we introduce the first universal adsorption model that accounts for detailed nanoparticle structural characteristics, metal composition, and different adsorbates by combining first principles calculations with machine learning. Our model fits a large number of data and accurately predicts adsorption trends on nanoparticles (both monometallic and alloy) that have not been previously seen. In addition to its application power, the model is simple and uses tabulated and rapidly calculated data for metals and adsorbates. We connect adsorption with stability behavior of nanoparticles, thus advancing the design of optimal nanoparticles for applications of interest, such as catalysis.
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46
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Cowan MJ, Mpourmpakis G. Structure-property relationships on thiolate-protected gold nanoclusters. Nanoscale Adv 2019; 1:184-188. [PMID: 36132447 PMCID: PMC9473222 DOI: 10.1039/c8na00246k] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 11/23/2018] [Indexed: 06/11/2023]
Abstract
Since their discovery, thiolate-protected gold nanoclusters (Au n (SR) m ) have garnered a lot of interest due to their fascinating properties and "magic-number" stability. However, models describing the thermodynamic stability and electronic properties of these nanostructures as a function of their size are missing in the literature. Herein, we employ first principles calculations to rationalize the stability of fifteen experimentally determined gold nanoclusters in conjunction with a recently developed thermodynamic stability theory on small Au nanoclusters (≤102 Au atoms). Our results demonstrate that the thermodynamic stability theory can capture the stability of large, atomically precise nanoclusters, Au279(SR)84, Au246(SR)80, and Au146(SR)57, suggesting its applicability over larger cluster size regimes than its original development. Importantly, we develop structure-property relationships on Au nanoclusters, connecting their ionization potential and electron affinity to the number of gold atoms within the nanocluster. Altogether, a computational scheme is described that can aid experimental efforts towards a property-specific, targeted synthesis of gold nanoclusters.
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Affiliation(s)
- Michael J Cowan
- Department of Chemical and Petroleum Engineering, University of Pittsburgh Pittsburgh PA 15261 USA
| | - Giannis Mpourmpakis
- Department of Chemical and Petroleum Engineering, University of Pittsburgh Pittsburgh PA 15261 USA
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47
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Abstract
Density functional theory calculations reveal how optical spectra of [Au25(SR)18]q nanoclusters (q = −1, 0, +1) change with different ligands.
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48
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Cholewinski M, Dixit M, Mpourmpakis G. Computational Study of Methane Activation on γ-Al 2O 3. ACS Omega 2018; 3:18242-18250. [PMID: 31458402 PMCID: PMC6644128 DOI: 10.1021/acsomega.8b02554] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 12/12/2018] [Indexed: 06/10/2023]
Abstract
The C-H activation of methane remains a longstanding challenge in the chemical industry. Metal oxides are attractive catalysts for the C-H activation of methane due to their surface Lewis acid-base properties. In this work, we applied density functional theory calculations to investigate the C-H activation mechanism of methane on various sites of low-index facets of γ-Al2O3. The feasibility of C-H activation on different metal-oxygen (acid-base) site pairs was assessed through two potential mechanisms, namely, the radical and polar. The effect of surface hydroxylation on C-H activation was also investigated to examine the activity of γ-Al2O3 under realistic catalytic surface conditions (hydration). On the basis of our calculations, it was demonstrated that the C-H activation barriers for polar pathways are significantly lower than those of the radical pathways on γ-Al2O3. We showed that the electronic structure (s- and p-band center) for unoccupied and occupied bands can be used to probe site-dependent Lewis acidity and basicity and the associated catalytic behavior. We identified the dissociated H2 binding and final state energy as C-H activation energy descriptors for the preferred polar pathway. Finally, we developed structure-activity relationships for the C-H activation of methane on γ-Al2O3 that account for surface Lewis acid-base properties and can be utilized to accelerate the discovery of catalysts for methane (and shale gas) upgrade.
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49
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Abstract
Heterometal doping is a promising avenue toward tailoring properties of ligand-protected metal nanoclusters for specific applications. Though successful doping has been demonstrated in several structures, the underlying reasons for the dopant preference on occupying specific locations on the nanocluster with different concentrations remain unclear. In this study we apply our thermodynamic stability model, originally developed for ligand-protected monometallic nanoclusters, to rationalize the synthetic accessibility, dopant location, and concentrations of various heterometals on ligand-protected Au nanoclusters. Importantly, we demonstrate that the thermodynamic stability theory is a significant step forward in accurately describing doping effects on nanoclusters using first-principles calculations. With our computational predictions being in excellent agreement with a series of experiments, we introduce the thermodynamic stability theory as a new method for bimetallic nanocluster prediction.
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Affiliation(s)
- Michael G Taylor
- Department of Chemical Engineering , University of Pittsburgh , Pittsburgh , Pennsylvania 15261 , United States
| | - Giannis Mpourmpakis
- Department of Chemical Engineering , University of Pittsburgh , Pittsburgh , Pennsylvania 15261 , United States
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50
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Affiliation(s)
- Pavlo Kostetskyy
- Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Carly M. Nolan
- Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Mudit Dixit
- Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Giannis Mpourmpakis
- Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
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