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de Donato A, Ghejan BA, Bakker JM, Bernhardt TM, Bromley ST, Lang SM. Gas-Phase Production of Hydroxylated Silicon Oxide Cluster Cations: Structure, Infrared Spectroscopy, and Astronomical Relevance. ACS EARTH & SPACE CHEMISTRY 2024; 8:1154-1164. [PMID: 38919856 PMCID: PMC11194846 DOI: 10.1021/acsearthspacechem.3c00346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 04/01/2024] [Accepted: 04/02/2024] [Indexed: 06/27/2024]
Abstract
The interaction of free cationic silicon oxide clusters, Si x O y + (x = 2-5, y ≥ x), with dilute water vapor, was investigated in a flow tube reactor. Product mass distributions indicate cluster size-dependent dissociative water adsorption. To probe the structure and vibrational spectra of the resulting Si x O y H2 + (x = 2-4) clusters, we employed infrared multiple photon dissociation spectroscopy and density functional theory calculations. The planar rhombic cluster core of the disilicon oxides (x = 2) appears to be retained upon dissociative adsorption of one H2O unit, whereas a significant structural transformation of the tri- and tetra-silicon oxides (x = 3 and 4) is induced, resulting in an increased coordination of the Si atoms and more 3D cluster structures. In an astronomical context, we discuss the potential relevance of Si x O y H z + clusters as seeds for dust nucleation and catalysts for carbon-based chemistry in diffuse or translucent interstellar clouds, where all the necessary conditions for producing these species are found. In the produced clusters, the frequency of the isolated silanol Si-OH stretching vibrational mode is considerably blue-shifted compared to that in hydroxylated bulk silica and small inorganic compounds. This mode has a characteristic frequency range between 1200 cm-1 (8.3 μm) and 1090 cm-1 (9.2 μm) and is associated with the anomalously small Si-OH bond lengths in these ionised species. In infrared observations such high frequency Si-O stretching modes are usually associated with a pure bulk silica component of silicate cosmic dust. The presence of Si x O y H2 + clusters in low silica astrophysical environments could thus potentially be detected via their signature Si-O band using the James Webb space telescope.
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Affiliation(s)
- Andreu
A. de Donato
- Departament
de Ciència de Materials i Química Física &
Institut de Química Teòrica i Computacio-nal (IQTCUB), Universitat de Barcelona, c/Martí i Franquès 1-11, Barcelona 08028, Spain
| | | | - Joost M. Bakker
- Radboud
University, Institute of Molecules and Materials, FELIX Laboratory, Nijmegen 6525 ED, The Netherlands
| | | | - Stefan T. Bromley
- Departament
de Ciència de Materials i Química Física &
Institut de Química Teòrica i Computacio-nal (IQTCUB), Universitat de Barcelona, c/Martí i Franquès 1-11, Barcelona 08028, Spain
- Institució
Catalana de Recerca i Estudis Avançats (ICREA), Passeig Lluís Companys 23, Bar-celona E-08010, Spain
| | - Sandra M. Lang
- Institute
of Surface Chemistry and Catalysis, University
of Ulm, Ulm 89069, Germany
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2
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Recio-Poo M, Morales-García Á, Illas F, Bromley ST. Tuning electronic levels in photoactive hydroxylated titania nanosystems: combining the ligand dipole effect and quantum confinement. NANOSCALE 2024. [PMID: 38618709 DOI: 10.1039/d3nr06189b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
Reducing the size of titania (TiO2) to the nanoscale promotes the photoactive anatase phase for use in a range of applications from industrial catalysis to environment remediation. The nanoscale dimensions of these systems affect the magnitude of the electronic energy gap by quantum confinement. Upon interaction with aqueous environments or water vapour, the surfaces of these systems will also be hydroxylated to some degree. In turn, this affects the electronic energy levels due to the cumulative electrostatic effect of the dipolar hydroxyl (-OH) ligands (i.e. the ligand dipole effect). Using accurate density functional calculations, we investigate the combined effects of quantum confinement and the hydration-induced ligand dipole effect on a set of realistic titania nanosystems over a wide range of hydroxylation. Our detailed investigation reveals that, contrary to previous models, the ligand dipole effect does not-linearly depend on the ligand coverage due to the formation of inter-ligand OH⋯OH hydrogen bonds. To account for the resulting effects, we propose a refined model, which describes the ligand dipole effect more accurately in our systems. We show that both hydroxylation (by the ligand dipole effect) and size (by quantum confinement) have significant but distinct impacts on the electronic energy levels in nanotitania. As an example, we discuss how variations in these effects can be used to tune the highest unoccupied energy level in nanotitania for enhancing the efficiency of the hydrogen evolution reaction. Overall, we show that any specific energy shift can be achieved by a range of different combinations of nanosystem size and degree of hydroxylation, thus providing options for energy-level tuning while also allowing consideration of practical constraints (e.g. synthetic limitations, operating conditions) for photochemical applications.
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Affiliation(s)
- Miguel Recio-Poo
- Departament de Ciència de Materials i Química Física & Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona, c/Martí i Franquès 1-11, 08028 Barcelona, Spain.
| | - Ángel Morales-García
- Departament de Ciència de Materials i Química Física & Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona, c/Martí i Franquès 1-11, 08028 Barcelona, Spain.
| | - Francesc Illas
- Departament de Ciència de Materials i Química Física & Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona, c/Martí i Franquès 1-11, 08028 Barcelona, Spain.
| | - Stefan T Bromley
- Departament de Ciència de Materials i Química Física & Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona, c/Martí i Franquès 1-11, 08028 Barcelona, Spain.
- Institució Catalana de recerca i Estudis Avançats (ICREA), Passeig Lluis Companys 23, 08010 Barcelona, Spain
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Neumark DM. Spectroscopy of Radicals, Clusters, and Transition States Using Slow Electron Velocity-Map Imaging of Cryogenically Cooled Anions. J Phys Chem A 2023; 127:4207-4223. [PMID: 37094039 DOI: 10.1021/acs.jpca.3c01537] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Slow electron velocity-map imaging of cryogenically cooled anions (cryo-SEVI) is a high-resolution variant of anion photoelectron spectroscopy that has been applied with considerable success over the years to the study of radicals, size-selected clusters, and transition states for unimolecular and bimolecular reactions. Cryo-SEVI retains the versatility of conventional anion photoelectron spectroscopy while offering sub-meV resolution, thereby enabling the resolution of vibrational structure in the photoelectron spectra of complex anions. This Feature Article describes recent experiments in our laboratory using cryo-SEVI, including a new research direction in which anions are vibrationally pre-excited with an infrared laser pulse prior to photodetachment.
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Affiliation(s)
- Daniel M Neumark
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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4
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Recio-Poo M, Morales-García Á, Illas F, Bromley ST. Crystal properties without crystallinity? Influence of surface hydroxylation on the structure and properties of small TiO 2 nanoparticles. NANOSCALE 2023; 15:4809-4820. [PMID: 36786054 DOI: 10.1039/d3nr00141e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Titania (TiO2) nanoparticles (NPs) are widely employed in applications that take advantage of their photochemical properties (e.g. pollutant degradation, photocatalysis). Here, we study the interrelation between crystallinity, surface hydroxylation and electronic structure in titania NPs with 1.4-2.3 nm diameters using all electron density functional theory-based calculations. We show how the distribution of local coordination environments of the atoms in thermally annealed quasi-spherical non-crystalline NPs converge to those in correspondingly sized faceted crystalline anatase NPs upon increasing hydroxylation. When highly hydroxylated, annealed NPs also possess electronic energy gaps with very similar energies and band edge orbital characters to those of the crystalline anatase NPs. We refer to the crystallite-mimicking non-crystalline annealed NPs as "crystalikes". Small stable crystalike NPs could allow for photochemical applications of titania in the size range where crystalline anatase NPs tend to become thermodynamically unfavoured (<3-5 nm). Our work implies the anatase crystal structure may not be as essential as previously assumed for TiO2 NP applications and generally suggests that crystalikes could be possible in other nanomaterials.
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Affiliation(s)
- Miguel Recio-Poo
- Departament de Ciència de Materials i Química Física & Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona, c/Martí i Franquès 1-11, 08028 Barcelona, Spain.
| | - Ángel Morales-García
- Departament de Ciència de Materials i Química Física & Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona, c/Martí i Franquès 1-11, 08028 Barcelona, Spain.
| | - Francesc Illas
- Departament de Ciència de Materials i Química Física & Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona, c/Martí i Franquès 1-11, 08028 Barcelona, Spain.
| | - Stefan T Bromley
- Departament de Ciència de Materials i Química Física & Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona, c/Martí i Franquès 1-11, 08028 Barcelona, Spain.
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Passeig Lluis Companys 23, 08010 Barcelona, Spain
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5
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Enhanced photocatalytic water splitting hydrogen production on TiO2 nanospheres: A theoretical- experimental approach. J Photochem Photobiol A Chem 2023. [DOI: 10.1016/j.jphotochem.2022.114212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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6
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González D, Sodupe M, Rodríguez-Santiago L, Solans-Monfort X. Surface morphology controls water dissociation on hydrated IrO 2 nanoparticles. NANOSCALE 2021; 13:14480-14489. [PMID: 34473817 DOI: 10.1039/d1nr03592d] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Iridium oxide is a highly efficient catalyst for the oxygen evolution reaction, whose large-scale application requires decreasing the metal content. This is achieved using small nanoparticles. The knowledge of the water-IrO2 nanoparticle interface is of high importance to understand the IrO2 behavior as electrocatalyst in aqueous solutions. In this contribution, DFT (PBE-D2) calculations and AIMD simulations on IrO2 nanoparticle models of different sizes ((IrO2)33 and (IrO2)115) are performed. Results show that two key factors determine the H2O adsorption energy and the preferred adsorption structure (molecular or dissociated water): metal coordination and hydrogen bonding with oxygen bridge atoms of the IrO2 surface. Regarding metal coordination, and since the tetragonal distortion existing in IrO2 is retained on the nanoparticle models, the adsorption at iridium axial vacant sites implies stronger Ir-H2O interactions, which favors water dissociation. In contrast, Ir-H2O interaction at equatorial vacant sites is weaker and thus the relative stability of molecular and dissociated forms becomes similar. Hydrogen bonding increases adsorption energy and favors water dissociation. Thus, tip and corner sites of the nanoparticle, with no oxygen bridge atoms nearby, exhibit the smallest adsorption energies and a preference for the molecular form. Overall, the presence of rather isolated tip and corner sites in the nanoparticle leads to lower adsorption energies and a smaller degree of water dissociation when compared with extended surfaces.
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Affiliation(s)
- Danilo González
- Departament de Química, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain.
| | - Mariona Sodupe
- Departament de Química, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain.
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Mino L, Morales-García Á, Bromley ST, Illas F. Understanding the nature and location of hydroxyl groups on hydrated titania nanoparticles. NANOSCALE 2021; 13:6577-6585. [PMID: 33885537 DOI: 10.1039/d1nr00610j] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
TiO2 nanoparticles (NPs) are intensively studied and widely used due to their huge potential in numerous applications involving their interaction with ultraviolet light (e.g., photocatalysis and sunscreens). Typically, these NPs are in water-containing environments and thus tend to be hydrated. As such, there is a growing need to better understand the physicochemical properties of hydrated TiO2 NPs in order to improve their performance in photochemical applications (e.g., photocatalytic water splitting) and to minimise their environmental impact (e.g., potential biotoxicity). To help address the need for reliable and detailed data on how nano-titania interacts with water, we present a systematic experimental and theoretical study of surface hydroxyl (OH) groups on photoactive anatase TiO2 NPs. Employing well-defined experimentally synthesised NPs and detailed realistic NP models, we obtain the measured and computed infrared spectra of the surface hydroxyls, respectively. By comparing the experimental and theoretical spectra we are able to identify the type and location of different OH groups in these NP systems. Specifically, our study allows us to provide unprecedented and detailed information about the coverage-dependent distribution of hydroxyl groups on the surface of experimental titania NPs, the degree of their H-bonding interactions and their associated assigned vibrational modes. Our work promises to lead to new routes for developing new and safe nanotechnologies based on hydrated TiO2 NPs.
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Affiliation(s)
- Lorenzo Mino
- Department of Chemistry and NIS Centre, University of Torino, via Giuria 7, 10125 Torino, Italy.
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8
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Yan C, Xu K, Liu R, Zhang T, Huang Z, Zheng C. The one-step synthesis of B,N co-doped carbon dots as a fracturing crosslinker and fluorescent tracer in flowback fluid and their performance. NEW J CHEM 2021. [DOI: 10.1039/d1nj04236j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The carbon dot crosslinker has a unique crosslinking mechanism, that each crosslinking point can crosslink multiple guar gum molecular chains.
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Affiliation(s)
- Chaozong Yan
- School of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu 610500, People's Republic of China
| | - Ke Xu
- PetroChina Research Institute of Petroleum Exploration & Development, Beijing, 100083, People's Republic of China
| | - Ruiping Liu
- PetroChina Tarim Oilfield Company, Dina Oil and Gas Development Department, Tarim, 841599, People's Republic of China
| | - Tailiang Zhang
- School of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu 610500, People's Republic of China
| | - Zhiyu Huang
- School of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu 610500, People's Republic of China
| | - Cunchuan Zheng
- School of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu 610500, People's Republic of China
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9
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Syzgantseva MA, Stepanov NF, Syzgantseva OA. Band Alignment as the Method for Modifying Electronic Structure of Metal-Organic Frameworks. ACS APPLIED MATERIALS & INTERFACES 2020; 12:17611-17619. [PMID: 32208619 DOI: 10.1021/acsami.0c02094] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Electronic-level ordering in metal-organic frameworks (MOFs) is a route to modulate their electronic properties such as optical absorption, band alignment, work function, charge separation, charge carrier lifetimes, and ground- or excited-state conductivity. A systematic application of this approach requires the knowledge on how a MOF chemical composition affects its electronic structure. In this work, the fundamental principles for selecting MOF components to achieve targeted level alignment are considered. Correlations between the electronic parameters of building blocks and MOF band structure are analyzed. The factors affecting the energy position of constituents are discussed. In particular, the impact of the chemical composition of ligands, including the structure of its scaffold and side groups, on their energy positions in MOFs is addressed. Besides, the effect of the choice of reference potential and surface termination on the band alignment is investigated. The performance of several density functionals in the computation of absolute band positions is assessed. Finally, general principles for the modification of the MOF electronic structure are formulated and the routes to achieve an appropriate band alignment with carrier-transporting materials, co-catalysts, and redox reaction potentials are suggested.
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Affiliation(s)
- Maria A Syzgantseva
- Laboratory of Quantum Mechanics and Molecular Structure, Department of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia
| | - Nikolay F Stepanov
- Laboratory of Quantum Mechanics and Molecular Structure, Department of Chemistry, Lomonosov Moscow State University, Moscow 119991, Russia
| | - Olga A Syzgantseva
- Laboratory of Molecular Simulation (LSMO), Institut des Sciences et Ingénierie Chimiques, Valais, Ecole Polytechnique Fédérale de Lausanne (EPFL), Rue de l'Industrie 17, CH-1951 Sion, Switzerland
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10
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Steenbergen KG, Gaston N. Ultra stable superatomic structure of doubly magic Ga 13 and Ga 13Li electrolyte. NANOSCALE 2020; 12:289-295. [PMID: 31825042 DOI: 10.1039/c9nr06959c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We report the extreme thermal stability of the superatomic electronic structure for 13-atom gallium clusters and the Ga13Li electrolyte. Using previously-validated first-principles simulations, [K. G. Steenbergen and N. Gaston, Phys. Rev. B: Condens. Matter Mater. Phys., 2013, 88, 161402-161405] we show that the superatomic shell progression of doubly-magic Ga13- remains stable up to 1000 K, making this cluster an ideal candidate for high-temperature applications requiring an exceptionally stable electronic structure. Using the neutral and cationic clusters for comparison, we quantify the extent to which cluster stability (geometric and electronic) is modified through addition or subtraction of a single electron. Finally, combining 13-atom gallium with lithium, we illustrate that superatomic closed-shell Ga13Li exhibits the same exceptionally high thermal stability as naked Ga13-. For technological use as a superatomic electrolyte, we demonstrate that Ga13Li has a low affinity to water as well as a low Li+ binding energy.
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Affiliation(s)
- Krista G Steenbergen
- The MacDiarmid Institute for Advanced Materials and Nanotechnology, School of Chemical and Physical Sciences, Victoria University of Wellington, P.O. Box 600, Wellington, New Zealand.
| | - Nicola Gaston
- The MacDiarmid Institute for Advanced Materials and Nanotechnology, Department of Physics, The University of Auckland, Private Bag 92019, Auckland, New Zealand
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11
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Macià Escatllar A, Morales-García Á, Illas F, Bromley ST. Efficient preparation of TiO2 nanoparticle models using interatomic potentials. J Chem Phys 2019; 150:214305. [DOI: 10.1063/1.5095071] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Affiliation(s)
- Antoni Macià Escatllar
- Departament de Ciència de Materials i Química Física & Institut de Química Teòrica i Computatcional (IQTCUB), Universitat de Barcelona, c/ Martí i Franquès 1-11, 08028 Barcelona, Spain
| | - Ángel Morales-García
- Departament de Ciència de Materials i Química Física & Institut de Química Teòrica i Computatcional (IQTCUB), Universitat de Barcelona, c/ Martí i Franquès 1-11, 08028 Barcelona, Spain
| | - Francesc Illas
- Departament de Ciència de Materials i Química Física & Institut de Química Teòrica i Computatcional (IQTCUB), Universitat de Barcelona, c/ Martí i Franquès 1-11, 08028 Barcelona, Spain
| | - Stefan T. Bromley
- Departament de Ciència de Materials i Química Física & Institut de Química Teòrica i Computatcional (IQTCUB), Universitat de Barcelona, c/ Martí i Franquès 1-11, 08028 Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Passeig Lluis Companys 23, 08010 Barcelona, Spain
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