26
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Muravev V, Simons JFM, Parastaev A, Verheijen MA, Struijs JJC, Kosinov N, Hensen EJM. Titelbild: Operando Spectroscopy Unveils the Catalytic Role of Different Palladium Oxidation States in CO Oxidation on Pd/CeO
2
Catalysts (Angew. Chem. 23/2022). Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202206435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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27
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Anastasiadou D, Beek Y, Hensen EJM, Costa Figueiredo M. Ammonia electrocatalytic synthesis from nitrate. ELECTROCHEMICAL SCIENCE ADVANCES 2022. [DOI: 10.1002/elsa.202100220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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28
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Boonyakarn T, Wiesfeld JJ, Asakawa M, Chen L, Fukuoka A, Hensen EJM, Nakajima K. Effective Oxidation of 5-Hydroxymethylfurfural to 2,5-Diformylfuran by an Acetal Protection Strategy. CHEMSUSCHEM 2022; 15:e202200059. [PMID: 35147297 DOI: 10.1002/cssc.202200059] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 02/11/2022] [Indexed: 06/14/2023]
Abstract
An acetal protection strategy for 5-hydroxymethylfurfural (HMF) was used to obtain 2,5-diformyfuran (DFF) using concentrated HMF solutions and a γ-Al2 O3 -supported Ru catalyst (Ru/γ-Al2 O3 ). The HMF-acetal with 1,3-propanediol can be oxidized to DFF-acetal with a yield of 84.0 % at an HMF conversion of 94.2 % from a 50 wt % solution. In contrast, aerobic oxidation of nonprotected HMF using a 10 wt % solution afforded DFF only in a moderate yield (52.3 %). Kinetic studies indicated that the six-membered ring acetal group not only prevents side reactions but also accelerates aerobic oxidation of the -CH2 OH moiety to -CHO under retention of the acetal functionality. Organic deposits formed during the reaction explained the significant decrease in the activity of the Ru/γ-Al2 O3 catalyst, which could be recovered neither by washing in water or organic solvents, nor by a calcination-reduction treatment. Sonication of the used Ru/γ-Al2 O3 catalyst in an aqueous NaOH solution successfully removed the deposits and allowed reuse of the catalyst for at least four times without activity loss.
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29
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Zhong Y, Su Y, Huang P, Jiang Q, Lin Y, Wu H, Hensen EJM, Abdelkader AM, Xi K, Lai C, Chou S. Polyoxometalate Ionic Sponge Enabled Dendrite-Free and Highly Stable Lithium Metal Anode. SMALL METHODS 2022; 6:e2101613. [PMID: 35152565 DOI: 10.1002/smtd.202101613] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Indexed: 06/14/2023]
Abstract
Metallic lithium batteries are holding great promises for revolutionizing the current energy storage technologies. However, the formation of dendrite-like morphology of lithium deposition caused by uneven distribution of Li+ might cause severe safety concerns of batteries. In this study, a polyoxometalate (POM) cluster, H5 PMo10 V2 O40 (PMo10 V2 ), is added to the conventional electrolyte that can construct a lithium-rich layer and inhibit the growth of Li dendrites effectively. The Li-rich layer can fill any lack of lithium ions on the surface of the metal anode, making the electric field strength consistent across the anode surface, thereby inhibiting the formation of lithium dendrites. Consequently, a significantly prolonged cyclic lifespan is obtained for both Li/Li symmetric cells and Li/LiCoO2 (Li/LCO) full cells. The cells with LCO positive maintains a high reversible specific capacity of 108.5 mAh g-1 after 300 cycles when electrolyte with PMo10 V2 additive is used, compared to 31.5 mAh g-1 for the untreated electrolyte. The findings indicate that POMs endowed as "ionic sponge" can be widely deployed in lithium metal batteries.
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30
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Chai J, Pestman R, Chen W, Donkervoet N, Dugulan AI, Men Z, Wang P, Hensen EJM. Isotopic Exchange Study on the Kinetics of Fe Carburization and the Mechanism of the Fischer–Tropsch Reaction. ACS Catal 2022. [DOI: 10.1021/acscatal.1c05634] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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31
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Li S, van de Poll RCJ, Kosinov N, Hensen EJM. Facile synthesis of nanosized mordenite and beta zeolites with improved catalytic performance: non-surfactant diquaternary ammonium compounds as structure-directing agents. Inorg Chem Front 2022. [DOI: 10.1039/d2qi00696k] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Nanosized MOR and BEA zeolites were directly synthesized using simple diquaternary ammonium compounds. The nanosized zeolites show improved catalytic performance in Friedel–Crafts and n-alkane hydroconversion reactions.
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32
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Guo Y, Hong X, Su Y, Luo W, Yu R, Wu J, Hensen EJM, Mai L, Cao Y. Sub-Nanometer Confined Ions and Solvent Molecules Intercalation Capacitance in Microslits of 2D Materials. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 17:e2104649. [PMID: 34677910 DOI: 10.1002/smll.202104649] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 08/28/2021] [Indexed: 06/13/2023]
Abstract
The ion intercalation behavior in 2D materials is widely applied in energy storage, electrocatalysis, and desalination. However, the detailed effect of ions on the performance, combining the influence of interlayer force and the change of solvent shell, is far less well understood. Here the solvated alkali metal ions with different sizes are intercalated into the lattice of 2D materials with different spacings (Ti3 C2 Tx , δ-MnO2 , and reduced graphene oxide) to construct the intercalation model related with sub-nanometer confined ions and solvent molecules to further understand the intercalation capacitance. Based on electrochemical methods and density functional theory calculation, the ions lose the electrostatic shielding solvent shell or shorten the distance between the layers, resulting in a significant increase in capacitance. It is found that the intercalation capacitance arises from the diffusion of solvated ions and is controlled by quantum and electrochemical capacitance for desolvated ions. This effect of solvation structure on performance can be applied in a variety of electrochemical interface studies and provides a new research view for energy storage mechanisms.
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33
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Liu Y, Zhang H, Wijpkema ASG, Coumans FJAG, Meng L, Uslamin EA, Longo A, Hensen EJM, Kosinov N. Understanding the Preparation and Reactivity of Mo/ZSM-5 Methane Dehydroaromatization Catalysts. Chemistry 2021; 28:e202103894. [PMID: 34822193 PMCID: PMC9299926 DOI: 10.1002/chem.202103894] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Indexed: 11/14/2022]
Abstract
Methane dehydroaromatization is a promising reaction for the direct conversion of methane to liquid hydrocarbons. The active sites and the mechanism of this reaction remain controversial. This work is focused on the operando X‐ray absorption near edge structure spectroscopy analysis of conventional Mo/ZSM‐5 catalysts during their whole lifetime. Complemented by other characterization techniques, we derived spectroscopic descriptors of molybdenum precursor decomposition and its exchange with zeolite Brønsted acid sites. We found that the reduction of Mo‐species proceeds in two steps and the active sites are of similar nature, regardless of the Mo content. Furthermore, the ZSM‐5 unit cell contracts at the beginning of the reaction, which coincides with benzene formation and it is likely related to the formation of hydrocarbon pool intermediates. Finally, although reductive regeneration of used catalysts via methanation is less effective as compared to combustion of coke, it does not affect the structure of the catalysts.
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34
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Zhu J, Cannizzaro F, Liu L, Zhang H, Kosinov N, Filot IAW, Rabeah J, Brückner A, Hensen EJM. Ni-In Synergy in CO 2 Hydrogenation to Methanol. ACS Catal 2021; 11:11371-11384. [PMID: 34557327 PMCID: PMC8453486 DOI: 10.1021/acscatal.1c03170] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 08/14/2021] [Indexed: 11/28/2022]
Abstract
Indium oxide (In2O3) is a promising catalyst for selective CH3OH synthesis from CO2 but displays insufficient activity at low reaction temperatures. By screening a range of promoters (Co, Ni, Cu, and Pd) in combination with In2O3 using flame spray pyrolysis (FSP) synthesis, Ni is identified as the most suitable first-row transition-metal promoter with similar performance as Pd-In2O3. NiO-In2O3 was optimized by varying the Ni/In ratio using FSP. The resulting catalysts including In2O3 and NiO end members have similar high specific surface areas and morphology. The main products of CO2 hydrogenation are CH3OH and CO with CH4 being only observed at high NiO loading (≥75 wt %). The highest CH3OH rate (∼0.25 gMeOH/(gcat h), 250 °C, and 30 bar) is obtained for a NiO loading of 6 wt %. Characterization of the as-prepared catalysts reveals a strong interaction between Ni cations and In2O3 at low NiO loading (≤6 wt %). H2-TPR points to a higher surface density of oxygen vacancy (Ov) due to Ni substitution. X-ray photoelectron spectroscopy, X-ray absorption spectroscopy, and electron paramagnetic resonance analysis of the used catalysts suggest that Ni cations can be reduced to Ni as single atoms and very small clusters during CO2 hydrogenation. Supportive density functional theory calculations indicate that Ni promotion of CH3OH synthesis from CO2 is mainly due to low-barrier H2 dissociation on the reduced Ni surface species, facilitating hydrogenation of adsorbed CO2 on Ov.
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35
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Wang Y, Kalscheur J, Su YQ, Hensen EJM, Vlachos DG. Real-time dynamics and structures of supported subnanometer catalysts via multiscale simulations. Nat Commun 2021; 12:5430. [PMID: 34521852 PMCID: PMC8440615 DOI: 10.1038/s41467-021-25752-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 08/18/2021] [Indexed: 02/08/2023] Open
Abstract
Understanding the performance of subnanometer catalysts and how catalyst treatment and exposure to spectroscopic probe molecules change the structure requires accurate structure determination under working conditions. Experiments lack simultaneous temporal and spatial resolution and could alter the structure, and similar challenges hinder first-principles calculations from answering these questions. Here, we introduce a multiscale modeling framework to follow the evolution of subnanometer clusters at experimentally relevant time scales. We demonstrate its feasibility on Pd adsorbed on CeO2(111) at various catalyst loadings, temperatures, and exposures to CO. We show that sintering occurs in seconds even at room temperature and is mainly driven by free energy reduction. It leads to a kinetically (far from equilibrium) frozen ensemble of quasi-two-dimensional structures that CO chemisorption and infrared experiments probe. CO adsorption makes structures flatter and smaller. High temperatures drive very rapid sintering toward larger, stable/metastable equilibrium structures, where CO induces secondary structure changes only.
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36
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Carnis J, Kshirsagar AR, Wu L, Dupraz M, Labat S, Texier M, Favre L, Gao L, Oropeza FE, Gazit N, Almog E, Campos A, Micha JS, Hensen EJM, Leake SJ, Schülli TU, Rabkin E, Thomas O, Poloni R, Hofmann JP, Richard MI. Twin boundary migration in an individual platinum nanocrystal during catalytic CO oxidation. Nat Commun 2021; 12:5385. [PMID: 34508094 PMCID: PMC8433154 DOI: 10.1038/s41467-021-25625-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Accepted: 08/23/2021] [Indexed: 02/08/2023] Open
Abstract
At the nanoscale, elastic strain and crystal defects largely influence the properties and functionalities of materials. The ability to predict the structural evolution of catalytic nanocrystals during the reaction is of primary importance for catalyst design. However, to date, imaging and characterising the structure of defects inside a nanocrystal in three-dimensions and in situ during reaction has remained a challenge. We report here an unusual twin boundary migration process in a single platinum nanoparticle during CO oxidation using Bragg coherent diffraction imaging as the characterisation tool. Density functional theory calculations show that twin migration can be correlated with the relative change in the interfacial energies of the free surfaces exposed to CO. The x-ray technique also reveals particle reshaping during the reaction. In situ and non-invasive structural characterisation of defects during reaction opens new avenues for understanding defect behaviour in confined crystals and paves the way for strain and defect engineering.
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37
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van Etten MPC, Zijlstra B, Hensen EJM, Filot IAW. Enumerating Active Sites on Metal Nanoparticles: Understanding the Size Dependence of Cobalt Particles for CO Dissociation. ACS Catal 2021; 11:8484-8492. [PMID: 34306814 PMCID: PMC8294015 DOI: 10.1021/acscatal.1c00651] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 06/12/2021] [Indexed: 11/28/2022]
Abstract
Detailed understanding of structure sensitivity, a central theme in heterogeneous catalysis, is important to guide the synthesis of improved catalysts. Progress is hampered by our inability to accurately enumerate specific active sites on ubiquitous metal nanoparticle catalysts. We employ herein atomistic simulations based on a force field trained with quantum-chemical data to sample the shape of cobalt particles as a function of their size. Algorithms rooted in pattern recognition are used to identify surface atom arrangements relevant to CO dissociation, the key step in the Fischer-Tropsch (FT) reaction. The number of step-edge sites that can catalyze C-O bond scission with a low barrier strongly increases for larger nanoparticles in the range of 1-6 nm. Combined with microkinetics of the FT reaction, we can reproduce experimental FT activity trends. The stabilization of step-edge sites correlates with increasing stability of terrace nanoislands on larger nanoparticles.
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38
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Wu H, Li T, Maddala SP, Khalil ZJ, Joosten RRM, Mezari B, Hensen EJM, de With G, Friedrich H, van Bokhoven JA, Patterson JP. Studying Reaction Mechanisms in Solution Using a Distributed Electron Microscopy Method. ACS NANO 2021; 15:10296-10308. [PMID: 34077193 DOI: 10.1021/acsnano.1c02461] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Electron microscopy (EM) of materials undergoing chemical reactions provides knowledge of the underlying mechanisms. However, the mechanisms are often complex and cannot be fully resolved using a single method. Here, we present a distributed electron microscopy method for studying complex reactions. The method combines information from multiple stages of the reaction and from multiple EM methods, including liquid phase EM (LP-EM), cryogenic EM (cryo-EM), and cryo-electron tomography (cryo-ET). We demonstrate this method by studying the desilication mechanism of zeolite crystals. Collectively, our data reveal that the reaction proceeds via a two-step anisotropic etching process and that the defects in curved surfaces and between the subunits in the crystal control the desilication kinetics by directing mass transport.
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39
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Muravev V, Spezzati G, Su YQ, Parastaev A, Chiang FK, Longo A, Escudero C, Kosinov N, Hensen EJM. Interface dynamics of Pd–CeO2 single-atom catalysts during CO oxidation. Nat Catal 2021. [DOI: 10.1038/s41929-021-00621-1] [Citation(s) in RCA: 82] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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40
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Goryachev A, Pustovarenko A, Shterk G, Alhajri NS, Jamal A, Albuali M, Koppen L, Khan IS, Russkikh A, Ramirez A, Shoinkhorova T, Hensen EJM, Gascon J. A Multi‐Parametric Catalyst Screening for CO
2
Hydrogenation to Ethanol. ChemCatChem 2021. [DOI: 10.1002/cctc.202100302] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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41
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Zhang L, Spezzati G, Muravev V, Verheijen MA, Zijlstra B, Filot IAW, Su YQ, Chang MW, Hensen EJM. Improved Pd/CeO 2 Catalysts for Low-Temperature NO Reduction: Activation of CeO 2 Lattice Oxygen by Fe Doping. ACS Catal 2021; 11:5614-5627. [PMID: 34055456 PMCID: PMC8154324 DOI: 10.1021/acscatal.1c00564] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 03/25/2021] [Indexed: 11/28/2022]
Abstract
Developing better three-way catalysts with improved low-temperature performance is essential for cold start emission control. Density functional theory in combination with microkinetics simulations is used to predict reactivity of CO/NO/H2 mixtures on a small Pd cluster on CeO2(111). At low temperatures, N2O formation occurs via a N2O2 dimer over metallic Pd3. Part of the N2O intermediate product re-oxidizes Pd, limiting NO conversion and requiring rich conditions to obtain high N2 selectivity. High N2 selectivity at elevated temperatures is due to N2O decomposition on oxygen vacancies. Doping CeO2 by Fe is predicted to lead to more oxygen vacancies and a higher N2 selectivity, which is validated by the lower onset of N2 formation for a Pd catalyst supported on Fe-doped CeO2 prepared by flame spray pyrolysis. Activating ceria surface oxygen by transition metal doping is a promising strategy to improve the performance of three-way catalysts.
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42
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Mezari B, Magusin PCMM, Almutairi SMT, Pidko EA, Hensen EJM. Nature of Enhanced Brønsted Acidity Induced by Extraframework Aluminum in an Ultrastabilized Faujasite Zeolite: An In Situ NMR Study. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2021; 125:9050-9059. [PMID: 34055125 PMCID: PMC8154853 DOI: 10.1021/acs.jpcc.1c00356] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 04/07/2021] [Indexed: 06/12/2023]
Abstract
The enhancing effect of extraframework Al (EFAl) species on the acidity of bridging hydroxyl groups in a steam-calcined faujasite zeolite (ultrastabilized Y, USY) was investigated by in situ monitoring the H/D exchange reaction between benzene and deuterated zeolites by 1H MAS NMR spectroscopy. This exchange reaction involves Brønsted acid sites (BAS) located in sodalite cages and supercages. In a reference faujasite zeolite free from EFAl, both populations of BAS are equally and relatively slowly reactive toward C6H6. In USY, in stark contrast, the H/D exchange of sodalite hydroxyl groups is significantly faster than that of hydroxyl groups located in the faujasite supercages, even though benzene has only access to the supercages. This evidences selective enhancement of BAS near Lewis acidic EFAl species, which according to the NMR findings are located in the faujasite sodalite cages.
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43
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Carnis J, Gao L, Fernández S, Chahine G, Schülli TU, Labat S, Hensen EJM, Thomas O, Hofmann JP, Richard MI. Facet-Dependent Strain Determination in Electrochemically Synthetized Platinum Model Catalytic Nanoparticles. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 17:e2007702. [PMID: 33738928 DOI: 10.1002/smll.202007702] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 02/11/2021] [Indexed: 06/12/2023]
Abstract
Studying model nanoparticles is one approach to better understand the structural evolution of a catalyst during reactions. These nanoparticles feature well-defined faceting, offering the possibility to extract structural information as a function of facet orientation and compare it to theoretical simulations. Using Bragg Coherent X-ray Diffraction Imaging, the uniformity of electrochemically synthesized model catalysts is studied, here high-index faceted tetrahexahedral (THH) platinum nanoparticles at ambient conditions. 3D images of an individual nanoparticle are obtained, assessing not only its shape but also the specific components of the displacement and strain fields both at the surface of the nanocrystal and inside. The study reveals structural diversity of shapes and defects, and shows that the THH platinum nanoparticles present strain build-up close to facets and edges. A facet recognition algorithm is further applied to the imaged nanoparticles and provides facet-dependent structural information for all measured nanoparticles. In the context of strain engineering for model catalysts, this study provides insight into the shape-controlled synthesis of platinum nanoparticles with high-index facets.
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Zhu J, Ciolca D, Liu L, Parastaev A, Kosinov N, Hensen EJM. Flame Synthesis of Cu/ZnO-CeO 2 Catalysts: Synergistic Metal-Support Interactions Promote CH 3OH Selectivity in CO 2 Hydrogenation. ACS Catal 2021; 11:4880-4892. [PMID: 33898079 PMCID: PMC8057230 DOI: 10.1021/acscatal.1c00131] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 03/23/2021] [Indexed: 11/28/2022]
Abstract
![]()
The hydrogenation
of CO2 to CH3OH is an important
reaction for future renewable energy scenarios. Herein, we compare
Cu/ZnO, Cu/CeO2, and Cu/ZnO–CeO2 catalysts
prepared by flame spray pyrolysis. The Cu loading and support composition
were varied to understand the role of Cu–ZnO and Cu–CeO2 interactions. CeO2 addition improves Cu dispersion
with respect to ZnO, owing to stronger Cu–CeO2 interactions.
The ternary Cu/ZnO–CeO2 catalysts displayed a substantially
higher CH3OH selectivity than binary Cu/CeO2 and Cu/ZnO catalysts. The high CH3OH selectivity in comparison
with a commercial Cu–ZnO catalyst is also confirmed for Cu/ZnO–CeO2 catalyst prepared with high Cu loading (∼40 wt %).
In situ IR spectroscopy was used to probe metal–support interactions
in the reduced catalysts and to gain insight into CO2 hydrogenation
over the Cu–Zn–Ce oxide catalysts. The higher CH3OH selectivity can be explained by synergistic Cu–CeO2 and Cu–ZnO interactions. Cu–ZnO interactions
promote CO2 hydrogenation to CH3OH by Zn-decorated
Cu active sites. Cu–CeO2 interactions inhibit the
reverse water–gas shift reaction due to a high formate coverage
of Cu and a high rate of hydrogenation of the CO intermediate to CH3OH. These insights emphasize the potential of fine-tuning
metal–support interactions to develop improved Cu-based catalysts
for CO2 hydrogenation to CH3OH.
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45
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Yu M, Tormene N, Bolshakov A, Mezari B, Liutkova A, Kosinov N, Hensen EJM. Selective methanethiol-to-olefins conversion over HSSZ-13 zeolite. Chem Commun (Camb) 2021; 57:3323-3326. [PMID: 33725046 DOI: 10.1039/d1cc00397f] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A methanethiol-to-olefins (MtTO) equivalent of methanol-to-olefins (MTO) chemistry is demonstrated. CH3SH can be converted to ethylene and propylene in a similar manner as CH3OH over SSZ-13 zeolite involving a hydrocarbon pool mechansim. Methylated aromatic intermediates were identified by 13C NMR analysis. Comparison of MtTO and MTO chemistry provides clues about the mechanism of C-C bond formation and catalyst deactivation.
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46
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Luo S, Zhang L, Liao Y, Li L, Yang Q, Wu X, Wu X, He D, He C, Chen W, Wu Q, Li M, Hensen EJM, Quan Z. A Tensile-Strained Pt-Rh Single-Atom Alloy Remarkably Boosts Ethanol Oxidation. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2008508. [PMID: 33749954 DOI: 10.1002/adma.202008508] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 01/31/2021] [Indexed: 06/12/2023]
Abstract
The rational design and control of electrocatalysts at single-atomic sites could enable unprecedented atomic utilization and catalytic properties, yet it remains challenging in multimetallic alloys. Herein, the first example of isolated Rh atoms on ordered PtBi nanoplates (PtBi-Rh1 ) by atomic galvanic replacement, and their subsequent transformation into a tensile-strained Pt-Rh single-atom alloy (PtBi@PtRh1 ) via electrochemical dealloying are presented. Benefiting from the Rh1 -tailored Pt (110) surface with tensile strain, the PtBi@PtRh1 nanoplates exhibit record-high and all-round superior electrocatalytic performance including activity, selectivity, stability, and anti-poisoning ability toward ethanol oxidation in alkaline electrolytes. Density functional theory calculations reveal the synergism between effective Rh1 and tensile strain in boosting the adsorption of ethanol and key surface intermediates and the CC bond cleavage of the intermediates. The facile synthesis of the tensile-strained single-atom alloy provides a novel strategy to construct model nanostructures, accelerating the development of highly efficient electrocatalysts.
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47
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Wu L, Kolmeijer KE, Zhang Y, An H, Arnouts S, Bals S, Altantzis T, Hofmann JP, Costa Figueiredo M, Hensen EJM, Weckhuysen BM, van der Stam W. Stabilization effects in binary colloidal Cu and Ag nanoparticle electrodes under electrochemical CO 2 reduction conditions. NANOSCALE 2021; 13:4835-4844. [PMID: 33646213 DOI: 10.1039/d0nr09040a] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Nanoparticle modified electrodes constitute an attractive way to tailor-make efficient carbon dioxide (CO2) reduction catalysts. However, the restructuring and sintering processes of nanoparticles under electrochemical reaction conditions not only impedes the widespread application of nanoparticle catalysts, but also misleads the interpretation of the selectivity of the nanocatalysts. Here, we colloidally synthesized metallic copper (Cu) and silver (Ag) nanoparticles with a narrow size distribution (<10%) and utilized them in electrochemical CO2 reduction reactions. Monometallic Cu and Ag nanoparticle electrodes showed severe nanoparticle sintering already at low overpotential of -0.8 V vs. RHE, as evidenced by ex situ SEM investigations, and potential-dependent variations in product selectivity that resemble bulk Cu (14% for ethylene at -1.3 V vs. RHE) and Ag (69% for carbon monoxide at -1.0 V vs. RHE). However, by co-deposition of Cu and Ag nanoparticles, a nanoparticle stabilization effect was observed between Cu and Ag, and the sintering process was greatly suppressed at CO2 reducing potentials (-0.8 V vs. RHE). Furthermore, by varying the Cu/Ag nanoparticle ratio, the CO2 reduction reaction (CO2RR) selectivity towards methane (maximum of 20.6% for dense Cu2.5-Ag1 electrodes) and C2 products (maximum of 15.7% for dense Cu1-Ag1 electrodes) can be tuned, which is attributed to a synergistic effect between neighbouring Ag and Cu nanoparticles. We attribute the stabilization of the nanoparticles to the positive enthalpies of Cu-Ag solid solutions, which prevents the dissolution-redeposition induced particle growth under CO2RR conditions. The observed nanoparticle stabilization effect enables the design and fabrication of active CO2 reduction nanocatalysts with high durability.
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48
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Etzi Coller Pascuzzi M, Velzen M, Hofmann JP, Hensen EJM. On the Stability of Co
3
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Oxygen Evolution Electrocatalysts in Acid. ChemCatChem 2020. [DOI: 10.1002/cctc.202001428] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Kosinov N, Hensen EJM. Reactivity, Selectivity, and Stability of Zeolite-Based Catalysts for Methane Dehydroaromatization. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e2002565. [PMID: 32656906 DOI: 10.1002/adma.202002565] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 06/03/2020] [Indexed: 06/11/2023]
Abstract
Non-oxidative dehydroaromatization is arguably the most promising process for the direct upgrading of cheap and abundant methane to liquid hydrocarbons. This reaction has not been commercialized yet because of the suboptimal activity and swift deactivation of benchmark Mo-zeolite catalysts. This progress report represents an elaboration on the recent developments in understanding of zeolite-based catalytic materials for high-temperature non-oxidative dehydroaromatization of methane. It is specifically focused on recent studies, relevant to the materials chemistry and elucidating i) the structure of active species in working catalysts; ii) the complex molecular pathways underlying the mechanism of selective conversion of methane to benzene; iii) structure, evolution and role of coke species; and iv) process intensification strategies to improve the deactivation resistance and overall performance of the catalysts. Finally, unsolved challenges in this field of research are outlined and an outlook is provided on promising directions toward improving the activity, stability, and selectivity of methane dehydroaromatization catalysts.
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Wang Y, Su YQ, Hensen EJM, Vlachos DG. Finite-Temperature Structures of Supported Subnanometer Catalysts Inferred via Statistical Learning and Genetic Algorithm-Based Optimization. ACS NANO 2020; 14:13995-14007. [PMID: 33054171 DOI: 10.1021/acsnano.0c06472] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Single-atom catalysts (SACs) minimize noble metal utilization and can alter the activity and selectivity of supported metal nanoparticles. However, the morphology of active centers, including single atoms and subnanometer clusters of a few atoms, remains elusive due to experimental challenges. The computational cost to describe numerous cluster shapes and sizes makes direct first-principles calculations impractical. We present a computational framework to enable structure determination for single-atom and subnanometer cluster catalysts. As a case study, we obtained the low-energy structures of Pdn (n = 1-21) clusters supported on CeO2(111), which are critical components of automobile three-way catalysts. Trained on density functional theory data, a three-dimensional cluster expansion is established using statistical learning to describe the Hamiltonian and predict energies of supported Pdn clusters of any structure. Low-energy stable and metastable structures are identified using a Metropolis Monte Carlo-based genetic algorithm in the canonical ensemble at 300 K. We observe that supported single atoms sinter to form bilayer clusters, and large cluster isomers share similarities in both shape and energy. The findings elucidate the significance of the support and microstructure on cluster stability. We discovered a simple surrogate structure-energy model, where the energy per atom scales with the square root of the average first coordination number, which can be used to estimate energies and compare the stability of clusters. Our framework, applicable to any metal/support system, fills an important methodological gap to predict the stability of supported metal catalysts in the subnanometer regime.
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