Article
Chemistry, Physical
Mingyan Li, Shu Zhao, Jing Li, Xiao Chen, Yongjun Ji, Haijun Yu, Dingrong Bai, Guangwen Xu, Ziyi Zhong, Fabing Su
Summary: This study reports a heterogeneous 0.5Ru(delta+)/ZrO2 catalyst with excellent catalytic performance and recyclability for producing ethyltriethoxysilane through ethylene hydrosilylation. Structural characterizations and theoretical calculations reveal the atomic dispersion and unique electronic properties of the active Ru species on the catalyst, which has the potential to replace homogeneous catalysts for a greener hydrosilylation industry.
Article
Chemistry, Physical
Hongliang Zhang, Zhijie Xu, Wei Sun, Yangge Zhu, Daixiong Chen, Chenyang Zhang
Summary: In this paper, the hydroxylation behavior and molecular hydrophobicity of quartz surface were systematically studied. TGA-DSC analysis showed that the complete desorption of water on the quartz surface requires a temperature of 180.5 degrees C. FTIR spectra indicated weakened hydrogen bonds on the dehydrated sample compared to the hydrated sample. DFT calculations confirmed that the weakened hydrogen bonds are due to the partial desorption of water molecules in the hydroxyl hydration layer.
APPLIED SURFACE SCIENCE
(2023)
Article
Chemistry, Physical
Mengru Li, Axel Gross, R. Juergen Behm
Summary: In this study, the effect of increasing oxygen vacancies at the Ru-ZrO2 interface on CO adsorption properties was investigated. Density functional theory calculations revealed trends in O-vacancy formation energy, charge transfer, local density of states, CO adsorption energy, and C-O vibrational frequencies as a function of oxygen vacancies. The findings have implications for our understanding of electronic metal-support interactions in heterogeneous catalysis and the catalytic performance of catalysts supported on reducible oxides.
Article
Chemistry, Physical
Shilong Chen, Ali M. Abdel-Mageed, Mengru Li, Sebastian Cisneros, Joachim Bansmann, Jabor Rabeah, Angelika Brueckner, Axel Gross, R. Juergen Behm
Summary: In metal-support interactions, discrimination between electronic and structural effects is often difficult due to contributions from both. A combined experimental/theoretical study showed the direct action of EMSIs, excluding the impact of structural modifications like partial overgrowth of metal nanoparticles. Charge transfer from O-vacancies in the ZrOx surface region to adjacent Ru nanoparticles played a key role in enhancing catalytic activity.
JOURNAL OF CATALYSIS
(2021)
Article
Chemistry, Physical
Andreas Postl, Pit Pascal Patrick Hilgert, Alexander Markevich, Jacob Madsen, Kimmo Mustonen, Jani Kotakoski, Toma Susi
Summary: We estimated the migration barrier of carbon adatoms on freestanding monolayer graphene to be (0.33 ± 0.03) eV by quantifying its temperature-dependent electron knock-on damage.
Article
Chemistry, Physical
Xiaoyang Wang, Liang Zhang, Yuxiang Bu, Wenming Sun
Summary: The study investigates the effects of single atom Pt on oxygen vacancy migration and water dissociation on anatase TiO2(1 0 1) surface through first-principles calculations. Results show that Pt-ads and Pt-5c modes accelerate O-v migration, while Pt-2c and Pt-6c modes decelerate it. Oxygen-poor conditions favor Pt-ads and Pt-2c formation, while oxygen-rich conditions favor Pt-5c and Pt-6c formation.
APPLIED SURFACE SCIENCE
(2021)
Article
Materials Science, Multidisciplinary
Monrada Petchmark, Vithaya Ruangpornvisuti
Summary: Using DFT-D2 method, the hydrogen adsorption on various ZrO2 surfaces was evaluated, indicating that c-ZrO2(111) and m-ZrO2(111) surfaces, as well as surfaces with oxygen vacancies, have high potential for hydrogen storage. Additionally, t-ZrO2 (101), [t-ZrO2(101) + V-O], and [m-ZrO2 (111) + V-O] were suggested as potential materials for hydrogen sensing.
Article
Chemistry, Physical
Zequan Huang, Shanshan Ma, Bingyan Qu, Dongdong Li, Rulong Zhou
Summary: The migration and oxidation behaviors of a single V atom and V2 dimer on the anatase TiO2(101) surface were systematically studied using DFT calculations. The results reveal that the migration and oxidation of V species vary under different conditions, providing insights for the formation mechanism of sublayer vanadium oxides on TiO2 support.
APPLIED SURFACE SCIENCE
(2021)
Article
Chemistry, Physical
Matic Poberznik, Gabriela Herrero-Saboya, Darko Makovec, Darja Lisjak, Layla Martin-Samos
Summary: Barium hexaferrite (BHF) is a ferrimagnet that grows as platelets at the nanoscale, showing uniaxial magnetic anisotropy. The surface morphology of BHF nanoplatelets varies depending on the preparation conditions. Using ab initio thermodynamics, we found that the most stable surface terminations of BHF are the hydroxylated oxygen-terminated surfaces (12k-O) under Ba-poor and low pH conditions, and the hydroxylated 2b surface under high pH and Ba-rich conditions.
APPLIED SURFACE SCIENCE
(2023)
Article
Chemistry, Physical
Farahnaz Maleki, Gianfranco Pacchioni
Summary: This study investigates the effect of isovalent dopants on the chemical reactivity of tetragonal ZrO2 through first principles calculations. It was found that surface or subsurface sites are preferred, and dopants can change the local structure of the surface and introduce new empty states in the band gap, thus affecting the Lewis acid properties of the surface. Additionally, the study shows that steric and/or orbital effects of isovalent dopants on a catalyst surface are sufficient to change the reaction products compared to the undoped system.
Article
Chemistry, Physical
Anruo Luo, Jianhua Chen
Summary: In this paper, the activation mechanism of Ca2+, Fe3+, Cu2+ and Pb2+ on quartz surface is studied using density functional theory (DFT) for the first time. The results show that hydration of metal ions significantly influences their adsorption on quartz surface, and hydroxylation of metal ions facilitates their adsorption on quartz surface. This establishes a theoretical foundation that hydroxylation of metal ions is a prerequisite for their adsorption on quartz surface, shedding new light on the mechanism of quartz activation via metal ions and helping the design of novel activators.
APPLIED SURFACE SCIENCE
(2022)
Article
Chemistry, Physical
Hermann Detz, Valeria Butera
Summary: Single atom catalysts (SACs) have gained significant attention for their potential in catalysis and sustainability. This study investigates the potential utilization of Ru@MoS2 as a promising SAC for CO2 reduction reaction (CO2RR) through first principles simulations. The stability of Ru@MoS2 and the reaction paths leading to the production of CO and methanol were evaluated. The results highlight the potential of Ru@MoS2 as a highly efficient catalyst for converting CO2 to methanol, providing insights into the complex reaction mechanism for the development of improved catalytic systems.
MOLECULAR CATALYSIS
(2023)
Article
Materials Science, Multidisciplinary
Chenglong Qin, Yushu Yu, Zihan Xu, Jiguang Du, Liang Zhao, Gang Jiang
Summary: Density functional theory (DFT) calculations were used to study reactions on the surface of uranium monocarbide (UC) when in contact with O atoms and O2 molecules. The study found that the conventional GGA method can provide reasonable results for surface systems. The adsorption of O atoms was found to vary depending on coverage, with preference for adsorption at the hollow sites for 1 and 0.5 monolayers (ML) and atop the U atom for 0.25 ML. The diffusion properties of O atoms on the surface were found to be different for different diffusion paths. Surface adsorption of O2 was non-dissociative when adsorbed atop the U atom, but dissociative for other sites.
Article
Chemistry, Physical
Nur Umisyuhada Mohd Nor, Elham Mazalan, Chad Risko, Mark Crocker, Nor Aishah Saidina Amin
Summary: The photocatalytic activity of C-doped anatase-TiO2 (101) surfaces as a function of layer thickness was investigated using density functional theory methods. Results showed that C-doped O sites (C-O) were more stable in the bulk, while C-doped Ti sites (C-Ti) were more stable on the surface. CO defects introduced impurity states without affecting the band gap energy, enhancing light absorption in the visible and IR spectrum. C-Ti defects induced structural distortions, causing a red-shifted absorption.
APPLIED SURFACE SCIENCE
(2022)
Article
Chemistry, Applied
Ho Viet Thang, Farahnaz Maleki, Sergio Tosoni, Gianfranco Pacchioni
Summary: The nature and local environment of Au single atoms supported on four different oxides were studied using DFT +U calculations, with CO as a probe molecule. The stretching frequency of CO, omega(e), was used as a fingerprint to determine the binding site of the Au atom. By considering various scenarios for Au adsorption sites, it was found that reproducing the blue-shift in the stretching frequency of CO adsorbed on positively charged gold, Au delta+, was challenging for DFT methods. A comparative study using different DFT functionals and accurate quantum chemistry methods was performed to propose a tentative assignment for the observed frequency of CO adsorbed on Au-1/LaFeO3 single atom catalyst.
TOPICS IN CATALYSIS
(2022)
Article
Chemistry, Physical
Giovanni Di Liberto, Luis A. Cipriano, Gianfranco Pacchioni
Summary: This article investigates the relationship between metal atoms and their surrounding environment in single atom catalysts (SACs). The numerical experiments reveal that changing the active site or the surrounding environment can lead to significant variations in catalytic activity. The implications of this conclusion for modeling studies of SACs are discussed.
Article
Chemistry, Physical
Giovanni Di Liberto, Farahnaz Maleki, Gianfranco Pacchioni
Summary: This study conducted ab initio molecular dynamics simulations using density functional theory to investigate the pH-dependent surface chemistry of MgO, TiO2, and γ-Al2O3, successfully predicting the point-of-zero charge values and the proportions of charged species and neutral molecules on the surface as pH varies.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Physics, Condensed Matter
Tilak Das, Giovanni Di Liberto, Gianfranco Pacchioni
Summary: We investigated the impact of quantum confinement on the band gap of chalcogenides 2D nanostructures using density functional theory. The results showed that the convergence of the band gap with slab thickness is slow in some cases, and significant deviations from the bulk value are present even with few nm-thick sheets. The simulations were compared with experimental data and found to be quantitatively consistent. These findings are important for reliably describing quantum confinement effects in systems where experimental data are not available.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2022)
Article
Chemistry, Multidisciplinary
Juan J. Navarro, Mowpriya Das, Sergio Tosoni, Felix Landwehr, Jared P. Bruce, Markus Heyde, Gianfranco Pacchioni, Beatriz Roldan Cuenya, Frank Glorius
Summary: The study demonstrates that N-heterocyclic carbenes (NHCs) can bind covalently to copper oxide surfaces, indicating that NHCs can act as strong anchors on oxide surfaces.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Multidisciplinary Sciences
Ilaria Barlocco, Luis A. Cipriano, Giovanni Di Liberto, Gianfranco Pacchioni
Summary: This study investigates the impact of different exchange-correlation functionals on the catalytic activity of single atom catalysts in hydrogen and oxygen evolution reactions. The results show that the choice of functional can lead to significant deviations in the predicted activity for different transition metals.
ADVANCED THEORY AND SIMULATIONS
(2023)
Article
Chemistry, Physical
Giovanni Di Liberto, Sergio Tosoni
Summary: We investigated the interface between carbon nitride (C3N4) and phosphorene nanosheets (P-ene) using Density Functional Theory (DFT) calculations. The formation of the interface is driven by Van der Waals forces. The thickness of P-ene nanosheets determines the band edges offsets and the separation of charge carriers. The system transitions from a nearly type-II to a type-I junction as the thickness of P-ene increases.
Review
Chemistry, Physical
Sergio Tosoni, Giovanni Di Liberto, Ivana Matanovic, Gianfranco Pacchioni
Summary: In this tutorial review, the state-of-the-art modeling approaches of Single Atom Catalysts (SAC) for water splitting and fuel cells reactions are reported. The discussion focuses on Hydrogen Evolution Reaction (HER), Oxygen Reduction Reaction (OER), Hydrogen Oxidation Reaction (HOR), and Oxygen Reduction Reaction (ORR). The aim is to emphasize the relevant aspects of SACs modeling and provide guidance for computational chemists and experimentalists. The review covers methodologies, prediction of electronic properties, validation of structural models, prediction of catalytic activity and selectivity, and analysis of current challenges and limitations.
JOURNAL OF POWER SOURCES
(2023)
Article
Nanoscience & Nanotechnology
Farahnaz Maleki, Giovanni Di Liberto, Gianfranco Pacchioni
Summary: In this work, the pH- and facet-dependent surface chemistry of TiO2/water interfaces was studied using ab initio molecular dynamics simulations. Acid-base equilibrium constants were determined at the interface, allowing for estimation of the pH at the point of zero charge, an important experimental observable. The amount of H+, OH-, and adsorbed H2O species on the surfaces was predicted based on simulated equilibrium constants, providing insights into water splitting semi-reactions. The complex morphology of TiO2 particles was approximated by considering different surfaces.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Chemistry, Physical
Sergio Tosoni
Summary: Mn3O4 Hausmannite thin films supported on (Cu, Ag, Au) coinage metals were investigated using DFT calculations. The interface between the films and metal support exhibited different lattice and ionic match, leading to different interactions. The films on Cu (111) and Au (111) weakly adhered due to unfavorable structural match, while strong adhesion was observed on Ag(100) with commensurate lattice and epitaxial growth. A negative charge flow from the support to the film was reported, resulting in the reduction of the film and an increase in magnetic moments of metal ions in the octahedral sublattice. The ferrimagnetic ordering varied in supported films exposing different crystal faces.
APPLIED SURFACE SCIENCE
(2023)
Article
Chemistry, Multidisciplinary
Alexander Fuhrich, Joachim Paier, Sergio Tosoni, Adrian Leandro Lewandowski, Leonard Gura, Wolf-Dieter Schneider, Gianfranco Pacchioni, Hans-Joachim Freund
Summary: Two-dimensional oxide films, including silica, germania, and mixed silica-germania films, supported on a Ru(0001) single crystal surface were studied. The modification of the properties of silica films through the incorporation of germanium atoms was investigated. X-ray photoelectron spectroscopy in combination with LEED and I/V LEEM measurements were used to judge the formation of mixed films.
ISRAEL JOURNAL OF CHEMISTRY
(2023)
Article
Chemistry, Physical
Tilak Das, Sergio Tosoni
Summary: A self-consistent Hubbard-U search was conducted on the bulk honeycomb layered oxide SrRu2O6 for potential applications as Li and post-Li battery cathode materials. The study employed first-principles density functional theory (DFT) based calculations and analysis. The results revealed that intercalation of Li, Ca, and Al metals did not affect the SRO magnetic ordering. The host SRO showed a quenched magnetic moment after intercalation, indicating the transfer of electrons to neighboring Ru sublattices.
SOLID STATE IONICS
(2023)
Review
Chemistry, Physical
Giovanni Di Liberto, Ilaria Barlocco, Livia Giordano, Sergio Tosoni, Gianfranco Pacchioni
Summary: This article discusses several fundamental elements required for successful computational modeling of single-atom catalysts (SACs) for electrocatalytic applications, including the role of the adopted exchange-correlation functional within a given DFT approach and the role of the local coordination of the active transition metal atom. Next, it explores new intermediates that can form on SACs, which are not present on extended metal electrodes, and how to model solvation, with a focus on the dual role of water as both a solvent and a ligand on SACs. Finally, challenges related to the inclusion of pH and voltage in models and some open issues concerning the rational design of new SACs are discussed.
CURRENT OPINION IN ELECTROCHEMISTRY
(2023)
Article
Chemistry, Physical
Ilaria Barlocco, Giovanni Di Liberto, Gianfranco Pacchioni
Summary: Single Atom Catalysts (SACs) bridge the gap between homogenous and heterogenous catalysis and show promise in various chemical reactions, including water splitting. This study focuses on SACs embedded in Covalent Organic Frameworks (COFs) and investigates their reactivity in Hydrogen and Oxygen Evolution Reactions (HER and OER, respectively) using density functional theory (DFT). The results reveal the formation of unique intermediates and shed light on the reaction mechanism, providing valuable insights for the design of novel catalytic materials.
Article
Chemistry, Multidisciplinary
Giovanni Di Liberto, Sergio Tosoni, Luis A. Cipriano, Gianfranco Pacchioni
Summary: Single-atom catalysis is a highly investigated topic in the catalytic community, offering advantages such as the use of minimal precious metals, higher selectivity, and bridging homogeneous and heterogeneous catalysis. The combination of advanced characterization techniques and theoretical calculations can provide a conceptual framework to better understand structure-function relationships.
ACCOUNTS OF MATERIALS RESEARCH
(2022)
Article
Chemistry, Physical
Farahnaz Maleki, Gianfranco Pacchioni
Summary: The characterization of catalytic oxide surfaces is often done by studying the properties of adsorbed probe molecules. In this study, DFT+D calculations were performed to investigate the adsorption properties of trimethylphosphine (TMP) on different oxide surfaces. The aim was to identify trends or patterns that can help correlate the P-31 chemical shift with physico-chemical properties of the oxide surfaces. The results showed that a simple correlation can be found between the P-31 chemical shift and adsorption energy within the same oxide.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Erhao Gao, Wenjing Feng, Qi Jin, Li Han, Yi He
Summary: The influence of K-doping on the reactive oxygen species and elementary reactions of HCHO catalytic oxidation was investigated using density functional theory (DFT). The introduction of K-doping changed the electronic structures of Ce and O, facilitating the adsorption and activation of HCHO and O2 molecules, enhancing lattice oxygen mobility, and reducing the energy barrier for HCHO oxidation. K-doping also promoted the formation of hydroxyl groups, facilitating HCHO adsorption and oxidation.
Article
Chemistry, Physical
Hao Fu, Zhangliang Xu
Summary: In this study, the adsorption mechanisms and detection performance of formaldehyde, ammonia, and sulfur dioxide on undoped and metal-doped ZnO surfaces were investigated using density functional theory. The results showed that formaldehyde and ammonia were physically adsorbed on the undoped ZnO surface, while sulfur dioxide was weakly chemisorbed. The adsorption energy was enhanced when ZnO was doped with metals. These findings provide theoretical guidance for the application of ZnO substrate materials in gas sensitivity research.
Article
Chemistry, Physical
Atsushi Nomura, Tohru Kurosawa, Migaku Oda, Satoshi Demura, Shogo Kuwahara, Sora Kobayashi, Hideaki Sakata
Summary: The study investigates the tunneling spectra of 1T-TiSe2 in the CDW state and the dip structure below the Fermi level, aiming to determine whether this dip is a CDW gap. The answer to this question is crucial for understanding the driving mechanism of CDW.
Article
Chemistry, Physical
A. S. Petrov, D. I. Rogilo, A. I. Vergules, V. G. Mansurov, D. V. Sheglov, A. V. Latyshev
Summary: This study investigates Si mass transport and morphological transformations on the Si(111) surface during (root 3 x root 3)-Sn reconstruction formation and Si homoepitaxy. The research shows that the formation of different Sn phases at different temperatures affects the Si island nucleation and monatomic step shift, which in turn impact the morphology of the Sn/Si(111) interface. Electromigration-induced drift of disordered Sn domains leads to enhanced noncompensated Si mass transport and surface roughening.
Article
Chemistry, Physical
D. V. Gruznev, L. V. Bondarenko, A. Y. Tupchaya, A. A. Yakovlev, A. N. Mihalyuk, A. V. Zotov, A. A. Saranin
Summary: Deposition of thallium (Tl) onto the Au/Si(111)5 x 2 reconstruction followed by annealing results in the formation of a surface structure with 4 x 2 periodicity. The immiscibility of Au and Tl leads to the migration of Tl atoms over the Si chains. Thallium donates electrons to the surface, converting the metallic surface into an insulating state and altering the inter-chain distance within the array of Au atomic wires.
Article
Chemistry, Physical
Simone Giusepponi, Francesco Buonocore, Barbara Ferrucci, Massimo Celino
Summary: Using ab-initio calculations, the interaction between lead adatom and both clean and doped iron (100) surfaces was investigated. It was found that the lead adatom prefers to adsorb in the hollow site, which is more stable compared to the top and bridge sites, and in this position, it is energetically favorable over the iron adatom. Moreover, lead adsorbed in the hollow site of the iron (100) surface doped with chromium was found to create a more stable system compared to nickel-doped surfaces with an iron adatom in the same position. The study also explored inter-layer distances, bonding mechanisms, magnetic behaviors, and charge density differences. The results provide insights into the role of doping in the interaction between lead adatom and iron surface, and have implications for the analysis of corrosion processes caused by liquid lead.
Article
Chemistry, Physical
Shuo Zhang, Jin-Ho Choi
Summary: The recent synthesis of two-dimensional layered WSi2N4 has attracted attention due to its potential applications. This study investigates the catalytic performance of WSi2N4 monolayers with nitrogen vacancies in the hydrogen evolution reaction using first-principles calculations. The results show that the defective WSi2N4 monolayers exhibit remarkably high catalytic activity comparable to platinum catalysts. Electronic structure calculations also reveal the emergence of spin-polarized states due to the introduction of nitrogen vacancies.
Article
Chemistry, Physical
Xiaoyan Yu, Xin Cao, Wei Kang, Shanhua Chen, Ao Jiang, Yuhao Luo, Wenwei Deng
Summary: First-principles calculations were used to investigate the electronic properties of a TiO2 heterostructure modified with Bi2Te3 co-catalyst. The study revealed that the Bi2Te3/TiO2 interface introduced optimal band offsets, effectively suppressing electron-hole recombination and enhancing the utilization efficiency of photo-generated carriers. Additionally, the Bi2Te3 co-catalyst introduced extra catalytic active sites, further boosting the photo-catalytic hydrogen evolution efficiency.
Article
Chemistry, Physical
Filippo Longo, Emanuel Billeter, Selim Kazaz, Alessia Cesarini, Marin Nikolic, Aarati Chacko, Patrik Schmutz, Zbynek Novotny, Andreas Borgschulte
Summary: Alkaline water electrolysis is a simple and efficient method for renewable hydrogen production, utilizing cheap and abundant transition metals. The catalytic properties of Ni materials are enhanced by the formation of oxidized compounds on the surface. The high electrocatalytic activity of Ni (oxy)-hydroxides is directly related to water intercalation in the passivation layer, supporting the hypothesis of a water mediated OH- diffusion mechanism. The self-organization of the surface structure during passivation layer formation enables high electrode performance.
Article
Chemistry, Physical
Mohan Kumar Kuntumalla, Miriam Fischer, Alon Hoffman
Summary: By investigating the bonding, retention, and thermal stability of nitrogen in H-Diamond (100), it was found that nitrogen can partially recover its bonding with carbon atoms after high-temperature annealing, indicating a high thermal stability of nitrogen in diamond.
Article
Chemistry, Physical
Dong Yue, Liangying Wen, Rong Chen, Jianxin Wang, Zhongqing Yang
Summary: The adsorption behavior of Cl2 molecules on the TiC surface and the formation and transfer of reaction products were studied using first-principles ab initio calculations. The results show that the Cl atoms bonded to the surface Ti atoms are more stable, and the TiCl3 intermediate is easier to form than the TiCl2 intermediate.
Article
Chemistry, Physical
Yatao Wang, Peng Zhang, Hongjuan Li, Qiuju Xu, Shujun Liu, Xiaopeng Liu, Xuehua Guo, Yitao Li, Jinzhang Liu, Sen Dong, Zhi Wei Seh, Qianfan Zhang
Summary: In this study, the adsorption performance of two types of metal-organic frameworks (MOFs) for thiophene and benzene was experimentally investigated. The results showed that IZE-1 exhibited high selectivity and superior adsorption capacity for thiophene, especially at low concentrations. First-principles calculations and molecular dynamics simulations provided insights into the mechanism of thiophene adsorption and the high selectivity observed. This research demonstrates the potential of MOFs for thiophene adsorption, particularly at high concentrations.
