Article
Nanoscience & Nanotechnology
Shyama Charan Mandal, Biswarup Pathak
Summary: The study explored the mechanistic pathways for Cu-NC catalyst in CO2 hydrogenation reactions, finding that Cu-NC is selective towards C-2 based products with lower limiting potential compared to periodic surfaces. The findings suggest that Cu-NC based catalysts may be more promising for C-2 based products.
ACS APPLIED NANO MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Benedikt Wolff, Zheng-Wang Qu, Stefan Grimme, Martin Oestreich
Summary: This study presents a method for the enantioselective reduction of simple carbenium ions using cyclohexadienes with a hydridic C-H bond at an asymmetrically substituted carbon atom. Chiral cyclohexadienes are used as dihydrogen surrogates for the transfer hydrogenation of alkenes (styrenes). The reaction mechanism involves the initiation by trityl cation and a delicate intermolecular capture of a carbenium-ion intermediate by the chiral hydride source, resulting in good enantiomeric ratios of the reduction products.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Physical
Yang Song, Chaoquan Hu, Chang Li, Xuebing Xu
Summary: The butane dehydrogenation at different butane coverages on the Pt(111) surface was investigated using density functional theory (DFT) calculations. It was found that the coverage has a strong influence on the reaction activity but no obvious effect on the reaction pathway. Deeper dehydrogenation and primary occurrence of C-C bond cleavage were observed at lower coverage.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Physical
Carlos Jimenez-Orozco, Marc Figueras, Elizabeth Florez, Francesc Vines, Jose A. Rodriguez, Francesc Illas
Summary: Molybdenum carbides are a promising alternative to Pt-group metals for the hydrogenation of unsaturated hydrocarbons. Nanostructuring MoCy nanoparticles (NPs) can significantly enhance their catalytic activity, with certain stoichiometric and nonstoichiometric compositions showing excellent reactivity for ethylene binding and activation. Theoretical results suggest that NPs with a Mo/C < 1.08 exhibit advantageous characteristics for C2H4 binding, providing insights for the design of MoCy NPs as potential hydrogenation catalysts.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Chemistry, Physical
Amitabha Das, Shyama Charan Mandal, Biswarup Pathak
Summary: Electrochemical CO2 reduction is a promising method to increase the production of valuable products such as ethylene and ethanol. Cu catalysts are a potential choice for this process, but they suffer from poor intermediate adsorption. Polymer/organic additives can be used to adjust the active center of Cu catalysts. DFT calculations were performed on urea and formamide modified Cu(100) surfaces to study C-2 product generation, and the results were compared with the pure Cu(100) surface.
CATALYSIS SCIENCE & TECHNOLOGY
(2023)
Article
Chemistry, Multidisciplinary
Zhaorui Li, Kristin Werner, Lu Chen, Aiping Jia, Kun Qian, Jian-Qiang Zhong, Rui You, Lihui Wu, Liyuan Zhang, Haibin Pan, Xin-Ping Wu, Xue-Qing Gong, Shamil Shaikhutdinov, Weixin Huang, Hans-Joachim Freund
Summary: The study explores the interplay between surface and bulk in hydride formation in ceria (CeO2) using experiment and theoretical calculations. It shows that as the concentration of oxygen vacancies increases, hydride becomes more stable and surface hydride formation is kinetically favorable at relatively low temperatures. This information is important for understanding the reactivity of ceria-based catalysts in a hydrogen-rich atmosphere.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Chemistry, Physical
Hector Prats, Michail Stamatakis
Summary: Research has shown that transition metal carbides (TMCs) can serve as catalytically active supports for metal nanoclusters, leading to superior catalytic activity compared to traditional metal oxide supports. By carefully selecting elements with desired electronegativity for the host TMC and the metal cluster, it is possible to manipulate the charge density on the cluster hollow sites, facilitating the bonding of certain molecules. Furthermore, Pt, Pd, and Rh clusters supported on hexagonal TMC (001) facets are identified as having the highest potential catalytic activity and stability.
JOURNAL OF MATERIALS CHEMISTRY A
(2022)
Article
Chemistry, Multidisciplinary
Runcong Liu
Summary: In this study, the microkinetics of heterogeneously catalyzed hydrogenation reactions were analytically solved based on three coupled physical parameters, providing a dynamic view over the whole reaction process. Analytical expressions were given for simple and more complex hypothetical hydrogenation reactions, offering valid solutions under all reaction conditions in practice. This analytical approach can provide more guidance for optimizing the overall outcome or catalyst development compared to numerical solutions.
Article
Chemistry, Physical
Qitang Ma, Houyu Zhu, Dongyuan Liu, Rui Li, Tuya Li, Hao Ren, Wen Zhao, Yuan Pan, Yunqi Liu, Wenyue Guo
Summary: Supported sub-nano Ni clusters have significant magic structures on oxide surfaces, which are different from gas-phase Ni clusters. The morphological transformation of Ni clusters depends on the interplay between Ni-oxide and Ni-Ni interactions. The Ni-Ni interaction dominates on ZnO beyond Ni10 and leads to a double-layer structure, while on gamma-Al2O3(100), the morphological transition occurs at Ni7. Hydrogen coverage on Ni clusters induces the conversion of cluster morphology from layered 3D geometries to one-layer 2D structures. The most stable hydrogen-containing structures on ZnO and gamma-Al2O3 are Ni11H10 and Ni11H8, respectively, indicating enhanced reactivity in a hydrogen environment.
CATALYSIS SCIENCE & TECHNOLOGY
(2023)
Article
Chemistry, Physical
Guang-Qiang Yu, Wen-Jin Yin, Xi-Bo Li
Summary: This work investigates the effect of surface doping on the hydrogen evolution reaction (HER) activity of molybdenum carbides (MoC) using density functional theory (DFT). The study demonstrates that specific doping ranges can enhance the HER activity of MoC by modifying the hydrogen adsorption ability and charge redistribution.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Article
Chemistry, Multidisciplinary
Eva Schiebel, Maria Voccia, Laura Falivene, Inigo Gottker-Schnetmann, Lucia Caporaso, Stefan Mecking
Summary: The cyclophane structure can control steric pressure in metal catalysts, leading to improved efficiency and stability in ethylene polymerization.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Biochemistry & Molecular Biology
Amanda L. Kwan, Robert H. Morris
Summary: This article introduces the largest-scale asymmetric catalytic process for the industrial production of (S)-metolachlor, which is achieved through the hydrogenation of N-(2-ethyl-6-methylphenyl)-1-methoxypropan-2-imine. The authors propose a plausible proton-first, outer-sphere mechanism based on density functional theory calculations that explains the reduction of the sterically hindered bond in the imine.
Article
Chemistry, Multidisciplinary
Oriol Pique, Qi Hang Low, Albertus D. Handoko, Boon Siang Yeo, Federico Calle-Vallejo
Summary: The study explores the electrochemical CO and CO2 reduction reactions using copper catalysts and renewable electricity as a carbon-neutral route to produce commodity chemicals and fuels. By investigating the reduction of ethylene oxide as a proxy to late stages of CORR to ethylene, the mechanisms and structure sensitivity of Cu electrodes toward C-2 products are revealed.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Physical
Chang-Eun Kim, Jiwoo Lee, Aron Walsh, Vincenzo Lordi, David F. Bahr
Summary: This study used density functional theory to calculate the energy and electronic structure of graphene models with different curvatures and hydrogen adsorption sites. The study found that the orientation of ripples affects the bandgap of graphene, while the adsorption energy of hydrogen depends on the curvature. Adsorbed hydrogen alters the curvature, resulting in weakened adsorption on neighboring sites, explaining the experimentally observed dynamic equilibrium stoichiometry of hydrogenated graphene.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Multidisciplinary Sciences
Siwei Li, Ruochen Cao, Mingquan Xu, Yuchen Deng, Lili Lin, Siyu Yao, Xuan Liang, Mi Peng, Zirui Gao, Yuzhen Ge, Jin-Xun Liu, Wei-Xue Li, Wu Zhou, Ding Ma
Summary: The atomically dispersed Ir/alpha-MoC catalyst with high metal loading shows remarkable activity, selectivity, and stability for quinoline hydrogenation through a water-promoted hydrogenation mechanism. The strong interaction between Ir and alpha-MoC substrate enables high dispersion of Ir on the surface, leading to high reactivity and selectivity. The synthesis of high-loading atomically dispersed catalyst is a new strategy for efficient hydrogenation reactions.
NATIONAL SCIENCE REVIEW
(2022)
Article
Chemistry, Physical
David Vazquez-Parga, Anabel Jurado, Alberto Roldan, Francesc Vines
Summary: The adsorption and dissociation behaviors of carbon monoxide (CO) on 81 different transition metal surfaces were studied using density functional theory calculations. The study found that late-stage face-centered cubic transition metals weakly adsorb CO perpendicularly, while early-stage body-centered cubic transition metals have strong adsorption capacity. The d-band center was identified as the most effective descriptor for predicting the adsorption and co-adsorption behavior of CO, as well as activation energies.
APPLIED SURFACE SCIENCE
(2023)
Article
Chemistry, Physical
Andrey A. Koverga, Elizabeth Florez, Ana M. Gomez-Marin
Summary: This study investigates the interaction of bismuth and tellurium adatoms with platinum surfaces and their effects on the electronic properties and catalytic activity. The results show that the adatoms induce changes in the surface electronic properties, leading to a significant impact on the catalytic activity of platinum. The findings provide valuable insights into the factors that control catalytic activity.
APPLIED SURFACE SCIENCE
(2023)
Article
Chemistry, Physical
Fatemeh Arab, Fariba Nazari, Francesc Illas
Summary: Recognition of different structural patterns in different potential energy surface regions is important for understanding the details of physics and chemistry. This study used artificial neural networks to investigate the singlet potential energy surfaces of tetra atomic isomers of the biogenic system [H, C, N, O], and successfully constructed a unified model accurately describing all studied isomers. The developed model has high accuracy and captures the main features of the tetra atomic isomers.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2023)
Article
Chemistry, Physical
Carlos Jimenez-Orozco, Andrey A. Koverga, Elizabeth Florez, Jose A. Rodriguez
Summary: Based on density functional calculations, this study proposes the use of cheap tungsten carbide (WC) as a support of Pt for acetylene selective hydrogenation. The results show that Pt/α-WC(0001)-W surface has a remarkable capacity to achieve the selective hydrogenation of acetylene into ethylene, avoiding further hydrogenation reactions. This research provides a theoretical basis for further experimental and theoretical works.
Article
Chemistry, Physical
Carlos Jimenez-Orozco, Elizabeth Florez, Jose A. Rodriguez
Summary: Tungsten carbide (WC) behaves similar to platinum in catalysis and is used in hydrogenation processes. In this study, the ability of the C- and W-terminations of the alpha-WC(0001) surface to dissociate H2 molecules and produce different surface coverages (Theta(H)) was analyzed. The WC-C surface showed a higher capacity for H2 dissociation compared to WC-W. Both surfaces could achieve full coverage at mild ambient conditions, and the binding of adsorbates was hindered at high Theta(H), indicating the need to modulate Theta(H) according to the application. These findings provide insights into the capabilities of WC-based catalysts in hydrogenation-related reactions.
Article
Chemistry, Physical
Carlos Jimenez-Orozco, Elizabeth Florez, Francesc Vines, Jose A. Rodriguez, Francesc Illas
Summary: The ethylene hydrogenation catalyzed by MoCy nanoparticles was studied using density functional theory methods and several models. The effect of hydrogen coverage was examined in detail, and it was found that ethylene hydrogenation is feasible on specific MoCy nanostructures under different hydrogen coverages. The results also showed that C2H4 adsorption is feasible in a certain temperature and pressure range. The findings provide insights into the catalytic behavior of MoCy catalysts and offer a basis for future experimental studies.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Physical
Eleonora Romeo, Francesc Illas, Federico Calle-Vallejo
Summary: Incorporating solvent-adsorbate interactions is crucial in models of aqueous (electro)-catalytic reactions. Existing techniques are either computationally demanding or inaccurate. Microsolvation provides a trade-off between accuracy and computational expenses. This study presents a method to rapidly outline the first solvation shell of adsorbed species on transition-metal surfaces and evaluate their solvation energy. Dispersion corrections are generally not required, but caution is needed when water-water and water-adsorbate interactions are similar in magnitude.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Physical
Nestor Garcia-Romeral, Angel Morales-Garcia, Francesc Vines, Iberio de P. R. Moreira, Francesc Illas
Summary: The electronic ground state of Ti2C MXene was determined using density functional theory calculations, showing a magnetic ground state with antiferromagnetically coupled ferromagnetic layers. A spin model consistent with the nature of the chemical bond was presented, and the relevant magnetic coupling constants were extracted from energy differences using a mapping approach. The estimated Neel temperature is approximately 220 +/- 30 K, suggesting potential applications in spintronics and related fields.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Physical
Angel Morales-Garcia, Francesc Vines, Carmen Sousa, Francesc Illas
Summary: This Perspective provides a road map for computational heterogeneous photocatalysis, emphasizing the knowledge required to enhance the design of efficient photocatalysts. A plausible computational framework is suggested, focusing on the static and dynamic properties of relevant excited states and the involved chemistry in the reactions of interest. The road map involves explicitly exploring the nature of charge carriers, the excited-state potential energy surface, and its time evolution. Excited-state descriptors are introduced to locate and characterize the electrons and holes generated upon excitation. Nonadiabatic molecular dynamics simulations are proposed as a convenient tool to describe the time evolution of the photogenerated species and their propagation through the crystalline structure of the photoactive material, ultimately providing information about the charge carrier lifetime. Finally, it is claimed that a detailed understanding of the mechanisms of heterogeneously photocatalyzed reactions requires the analysis of the excited-state potential energy surface.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Multidisciplinary Sciences
Junsic Cho, Taejung Lim, Haesol Kim, Ling Meng, Jinjong Kim, Seunghoon Lee, Jong Hoon Lee, Gwan Yeong Jung, Kug-Seung Lee, Francesc Vines, Francesc Illas, Kai S. Exner, Sang Hoon Joo, Chang Hyuck Choi
Summary: Platinum single-atom catalysts show potential in heterogeneous electrocatalysis. The chemical nature of active Pt sites is not well understood, leading to discrepancies between experiments and theories. In this study, low-coordinated Pt-II species on carbon-based Pt single-atom catalysts were identified and found to play a critical role in the chlorine evolution reaction. This research offers guidelines for achieving high electrocatalytic performance in carbon-based single-atom catalysts.
NATURE COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Francesc Vines, Adria Calzada, Pablo Gamallo
Summary: Different nano-engineered grazynes were studied as membranes for separating methane and carbon dioxide. The study investigated the thermodynamics, kinetics, and dynamics of the process and compared the materials to others in the literature. The results showed that grazynes have low adsorption energy and diffusion energy barriers, making them excellent membranes for biogas upgrading with improved selectivity and larger quantity of separated CO2 per material gram.
JOURNAL OF CO2 UTILIZATION
(2023)
Article
Chemistry, Physical
Josei A. Rodriguez, Carlos Jimenez-Orozco, Elizabeth Florez, Francesc Vines, Francesc Illas
Summary: The studies in this Perspective demonstrate the utility of transition metal carbide (TMC) nanoparticles in activating and trapping molecules such as H-2, CH4, and CO2, which are essential in C-1 chemistry and greenhouse gas conversion. By combining experimental and theoretical approaches, the physical and chemical properties of these TMC systems have been elucidated, revealing their unique behavior and structures at the nanoscale. Theoretical and experimental investigations of supported and unsupported TMC nanoparticles are presented, along with an analysis of current challenges and potential applications.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Physical
Nestor Garcia-Romeral, Angel Morales-Garcia, Francesc Vines, Iberio de P. R. Moreira, Francesc Illas
Summary: The magnetic properties of Ti2C, Ti3C2, and Ti4C3 MXenes were studied using density functional theory. It was found that all MXenes exhibit magnetic behavior with antiferromagnetic coupling between the outer Ti layers. A spin model was proposed based on the analysis of the chemical bond, with diamagnetic Ti2+ ions in the inner layers and paramagnetic Ti+ centers on the surface. The magnetic coupling constants were found to depend on the functional used, with the nearest neighbor intralayer coupling always being ferromagnetic.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)