A5086443456- Catalytic Processes in Materials Science
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Electrocatalysts for Energy Conversion
- Advancements in Solid Oxide Fuel Cells
- Electronic and Structural Properties of Oxides
- Catalysis and Hydrodesulfurization Studies
- Catalysis and Oxidation Reactions
- Chemical Reaction Mechanisms
- Advanced Chemical Physics Studies
- Magnetic and transport properties of perovskites and related materials
- Catalysis for Biomass Conversion
- Molecular Junctions and Nanostructures
- Crystallography and molecular interactions
- Machine Learning in Materials Science
- Nanomaterials for catalytic reactions
- Spectroscopy and Quantum Chemical Studies
- Catalysts for Methane Reforming
- Fuel Cells and Related Materials
- Metal-Organic Frameworks: Synthesis and Applications
- Ammonia Synthesis and Nitrogen Reduction
- Copper-based nanomaterials and applications
- Organometallic Complex Synthesis and Catalysis
- nanoparticles nucleation surface interactions
- Advanced Photocatalysis Techniques
University of South Carolina
2015-2024
Software (Spain)
2017
Rikkyo University
2005-2009
Bharathidasan University
2005
The University of Tokyo
2004-2005
Kyoto University
2005
Kyushu University
2003
Osaka University
2003
Osaka Research Institute of Industrial Science and Technology
2003
Our civilization relies on synthetic polymers for all aspects of modern life; yet, inefficient recycling and extremely slow environmental degradation plastics are causing increasing concern about their widespread use. After a single use, many these materials currently treated as waste, underutilizing inherent chemical energy value. In this study, energy-rich polyethylene (PE) macromolecules catalytically transformed into value-added products by hydrogenolysis using well-dispersed Pt...
The development of porous well-defined hybrid materials (e.g., metal–organic frameworks or MOFs) will add a new dimension to wide number applications ranging from supercapacitors and electrodes “smart” membranes thermoelectrics. From this perspective, the understanding tailoring electronic properties MOFs are key fundamental challenges that could unlock full potential these materials. In work, we focused on insights responsible for three distinct classes bimetallic systems, Mx–yM′y-MOFs,...
Abstract Carbon–carbon bond cleavage reactions, adapted to deconstruct aliphatic hydrocarbon polymers and recover the intrinsic energy carbon value in plastic waste, have typically been catalysed by metal nanoparticles or air-sensitive organometallics. Metal oxides that serve as supports for these catalysts are considered be inert. Here we show Earth-abundant, non-reducible zirconia catalyses hydrogenolysis of polyolefins with activity rivalling precious nanoparticles. To harness this...
We have developed an integrated approach that combines synthesis, X-ray photoelectron spectroscopy (XPS) studies, and theoretical calculations for the investigation of active unsaturated metal sites (UMS) in copper-based metal–organic frameworks (MOFs). Specifically, extensive reduction Cu+2 to Cu+1 at MOF nodes was achieved. Introduction mixed valence copper resulted significant changes band structure increased density states near Fermi edge, thereby altering electronic properties...
Atomically dispersed supported metal catalysts offer unique opportunities for designing highly selective and maximizing the utility of precious metals that have potential applications in a wide variety industrial chemical reactions. Although substantial advances understanding origin activity such been made few reactions, reaction mechanisms nature active site—small clusters versus single atoms—are still debated. Using combination density functional theory microkinetic modeling, we confirm...
A critical role is traditionally assigned to transition states (TSs) and minimum energy pathways, or intrinsic reaction coordinates (IRCs), in interpreting organic reactivity. Such an interpretation, however, ignores vibrational kinetic effects of finite temperature. Recently it has been shown that reactions do not necessarily follow the intermediates along IRC. We report here molecular dynamics (MD) simulations show may alter chemical even more. In heterolysis rearrangement protonated...
Periodic density functional theory (DFT) calculations and microkinetic modeling are used to investigate the electrochemical oxidation of H2 fuel on (001) surface Sr2Fe1.5Mo0.5O6 (SFMO) perovskite under anodic solid oxide cell conditions. Three models with different Fe/Mo ratios in topmost layer-identified by ab initio thermodynamic analysis-are mechanism. A analysis that considers effects anode bias potential suggests a higher Mo concentration increases activity toward oxidation. At...
The selective hydrodeoxygenation (HDO) reaction is desirable to convert glycerol into various value-added products by breaking different numbers of C-O bonds while maintaining C-C bonds. Here we combine experimental and density functional theory (DFT) results reveal that the Cu modifier can significantly reduce oxophilicity molybdenum carbide (Mo2C) surface change product distribution. Mo2C active for all produce propylene. As coverage increases 0.5 monolayer (ML), Cu/Mo2C shows activity...
This paper presents a systematic approach to quantify uncertainties of various quantities interest (QoIs) in catalysis determined by microkinetic models developed from first principles. One the main sources uncertainty any simulation is attributed exchange-correlation approximations density functional theory (DFT) used calculate rate constants for all elementary reaction steps within transition state theory. These DFT are at core significant discrepancies between computational simulations...
Identifying the nature of an active site and understanding reaction mechanism at atomic level are critical importance in design efficient catalysts for targeted applications. While extended metal surfaces have been studied extensively various catalytic processes relative activities different metals were predicted using volcano relationships, much less is known with regard to catalysis metal/oxide interface sites. This Perspective focuses on recent computational studies that aimed such The...
The origin of unique catalytic activity a thiolate-bridged diruthenium complex in nucleophilic substitution reactions propargylic alcohols, which features diruthenium-allenylidene as key intermediate, was studied with the aid density functional calculations (B3LYP). Comparison mono- and systems has shown that rigid but reasonably flexible Ru-Ru core structure plays critical role catalyst turnover step (i.e., dissociative ligand exchange product pi-complex starting propargyl alcohol goes...
The growth, surface composition, and chemical activity of bimetallic Pt−Au clusters on TiO2(110) have been investigated. Scanning tunneling microscopy (STM) experiments demonstrate that the deposition Au Pt results in formation due to seeding mobile atoms at existing nuclei. composition top layer was studied by low energy ion scattering (LEIS) for bulk compositions ranging from 25%−87.5% with total metal coverages 0.25 0.50 ML. For both coverages, cluster surfaces consisted nearly pure 50%...
The redox and associative carboxyl pathways of the water–gas shift reaction have been investigated at a corner Pt site Pt/TiO2 (110) interface using density functional theory microkinetic modeling techniques. Overall rates calculated from model suggest that pathway dominates in temperature range 473–673 K oxygen vacancy structure plays critical role dissociating H2O. Because strong adsorption CO atoms, these sites are less active than edge low temperatures; however, activity atoms becomes...
Periodic density functional theory calculations and microkinetic modeling are used to investigate the associative carboxyl pathways of water-gas shift (WGS) reaction at Pt/CeO2 (111) interface. Analysis a model based on parameters obtained from first principles suggests that turnover frequencies for CO-assisted mechanism comparable experimental results. However, this containing various interface sites cannot explain experimentally observed activation barriers orders catalysts. Considering...
The interaction of Aun and Ptn (n=2,3) clusters with the stoichiometric partially reduced rutile TiO2 (110) surfaces has been investigated using periodic slab electrostatic embedded cluster models. Compared to Au clusters, Pt interact strongly both are able enhance reducibility surface, i.e., reduce oxygen vacancy formation energy. focus this study is effect Hartree–Fock exchange on description strength chemical bonds at interface Au/Pt surface. helps describing changes in electronic...
The oxidation mechanism of H2 fuel at the three-phase boundary Ni/YSZ has been investigated under experimental solid oxide cell conditions by a combination density functional theory and microkinetic modeling. It is shown that O migration pathway 2–4 orders magnitude faster than H spillover OH pathways. Bulk oxygen diffusion in YSZ rate-limiting low temperatures, transfer from Ni to form water becomes high temperatures.
The electronic structure of small Ptn (n = 1–8) clusters supported on the stoichiometric and partially reduced rutile TiO2(110) surface have been investigated using density functional theory. Pt atoms prefer to form a close-packed with (111) facet near an oxygen vacancy TiO2 support less dense (100) away from vacant sites. main focus this study is identifying realistic catalyst model for Pt/TiO2 interface under water-gas shift (WGS) reaction conditions. Constrained ab initio thermodynamic...
Pt–Re clusters supported on titania have shown promise as catalysts for the low temperature water–gas shift reaction. However, enhanced activity of bimetallic catalyst versus pure Pt is not well understood. In this work, exclusively were grown TiO2(110) by vapor-deposition 2 ML Re and clusters. Temperature programmed desorption experiments with CO used to determine concentration at surface, given that dissociates but Pt. Deposition resulted in core–Pt shell structures, whereas deposition...
Deoxydehydration (DODH) is an emerging biomass deoxygenation process whereby vicinal OH groups are removed.
Density functional theory and microkinetic reactor modeling were used to investigate the hydrodeoxygenation (HDO) mechanism of glycerol on oxygenated Mo2C catalyst surface understand activity product selectivity under practically relevant reaction conditions. Reactor simulations with multiple active site models predicted that a fully acid–base (OH,O) pairs is for dehydration it can selectively cleave one C–O bond produce 3-hydroxypropanal (HPA). The acid sites are not directly involved in...
The growth pattern of small Ptn (n = 1–10) clusters has been investigated on the stoichiometric and partially reduced ceria (111) surfaces using density functional theory. On both surfaces, metal packing was cubic-closed packed, starting from as Pt10, facet cluster clearly recognizable. main focus this article is identifying a realistic catalyst model for Pt/ceria surface under water–gas shift (WGS) reaction conditions. As result, interactions O, CO, H species with our chosen...