A5069905241- Graphene research and applications
- Surface Chemistry and Catalysis
- Electrocatalysts for Energy Conversion
- Advanced Chemical Physics Studies
- Catalytic Processes in Materials Science
- Molecular Junctions and Nanostructures
- Radioactive element chemistry and processing
- Iron oxide chemistry and applications
- Advancements in Battery Materials
- Ionic liquids properties and applications
- Carbon Dioxide Capture Technologies
- Electrochemical Analysis and Applications
- Concrete and Cement Materials Research
- Machine Learning in Materials Science
- Catalysis and Hydrodesulfurization Studies
- Nuclear Materials and Properties
- X-ray Diffraction in Crystallography
- Molten salt chemistry and electrochemical processes
- Chemical Thermodynamics and Molecular Structure
- Spectroscopy and Quantum Chemical Studies
- Membrane Separation and Gas Transport
- Catalysis and Oxidation Reactions
- 2D Materials and Applications
- Crystallization and Solubility Studies
- Catalysis for Biomass Conversion
Pacific Northwest National Laboratory
2017-2025
Government of the United States of America
2025
Le Quy Don Technical University
2021-2024
Institut de Biologie Structurale
2023
Vietnam Academy of Science and Technology
2015-2021
Richland College
2019-2021
The Abdus Salam International Centre for Theoretical Physics (ICTP)
2012-2016
Swiss Federal Laboratories for Materials Science and Technology
2009-2011
Max Planck Institute for Polymer Research
2010
University of Bern
2010
We report on a combined scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS), and density functional theory (DFT) study the surface-assisted assembly of hexaiodo-substituted macrocycle cyclohexa-m-phenylene (CHP) toward covalently bonded polyphenylene networks Cu(111), Au(111), Ag(111) surfaces. STM XPS indicate room temperature dehalogenation CHP either surface, leading to surface-stabilized radicals (CHPRs) coadsorbed iodine. Subsequent covalent intermolecular bond...
Adsorption and dissociation of water on different oxygen- iron-terminated hematite(0001) surfaces at monolayer coverage have been studied by density-functional theory calculations, including a Hubbard-like+U correction. We considered six possible surface terminations, four two iron-terminations. Binding energy these terminations can be as large 1.0 eV. On the barrier for molecularly adsorbed is less than 0.3 eV, in few cases even spontaneous, i.e., without any detectable barrier. Our results...
We present a perspective on the computational determination of entropy and its effects consequences heterogeneous catalysis. Special attention is paid to role anharmonicity (a result collective phenomena) deviations from standard harmonic oscillator approximations, which can fail provide reliable assessment entropy. To address these challenges, advanced methodologies are needed that explicitly account for thermodynamic drivers through appropriate statistical sampling reactive free-energy...
A detailed mechanistic study of the electrochemical hydrogenation aldehydes is presented toward goal identifying how organic molecules in solution behave at interface with charged surfaces and what best manner to convert them. Specifically, this focuses on designing an electrocatalytic route for ambient-temperature postpyrolysis treatment bio-oil. Aldehyde reductions are needed biomass into fuels or chemicals. combined experimental computational approach taken catalyst design provide...
Abstract The on‐surface polymerization of 1,3,6,8‐tetrabromopyrene (Br 4 Py) on Cu(111) and Au(111) surfaces under ultrahigh vacuum conditions was investigated by a combination scanning tunneling microscopy (STM), X‐ray photoelectron spectroscopy (XPS) density functional theory (DFT) calculations. Deposition Br Py held at 300 K resulted in spontaneous debromination reaction, generating the formation branched coordination polymer network stabilized C−Cu−C bonds. After annealing 473 K, bonds...
To resolve the fleeting structures of lanthanide Ln3+ aqua ions in solution, we (i) performed first ab initio molecular dynamics (AIMD) simulations entire series explicit water solvent using pseudopotentials and basis sets recently optimized for lanthanides (ii) measured symmetry hydrating waters about (Nd3+, Dy3+, Er3+, Lu3+) time with extended X-ray absorption fine structure (EXAFS). EXAFS spectra were experimentally generated from AIMD trajectories to directly compare simulation, which...
Single-atom catalysts are often reported to have catalytic properties that surpass those of nanoparticles, while a direct comparison sites common and different for both is lacking. Here we show single atoms Pt-group metals embedded into the surface Fe3O4 greatly enhanced interaction strength with CO2 compared surface. The strong adsorption on Rh corresponding low activation energies lead 2 orders magnitude higher conversion rates nanoparticles. This high activity stems from partially oxidic...
Enhanced sampling ab initio simulations enable to study chemical phenomena in catalytic systems including thermal effects & anharmonicity, collective dynamics describing enthalpic entropic contributions, which can significantly impact on reaction free energy landscapes.
Research interest in single-atom catalysts (SACs) has been continuously increasing. However, the lack of understanding dynamic behaviors SACs during applications hinders catalyst development and mechanistic understanding. Herein, we report on evolution active sites over Pd/TiO2-anatase SAC (Pd1/TiO2) reverse water-gas shift (rWGS) reaction. Combining kinetics, situ characterization, theory, show that at T ≥ 350 °C, reduction TiO2 by H2 alters coordination environment Pd, creating Pd with...
Abstract Carbon capture, utilization and storage is a key yet cost-intensive technology for the fight against climate change. Single-component water-lean solvents have emerged as promising materials post-combustion CO 2 but little known regarding their mechanism of action. Here we present combined experimental modelling study single-component solvents, find that capture accompanied by self-assembly reverse-micelle-like tetrameric clusters in solution. This spontaneous aggregation leads to...
Solvation and ion valency effects on selectivity of metal oxyanions at redox–polymer interfaces are explored through in situ spatial-temporally resolved neutron reflectometry combined with large scale ab initio molecular dynamics. The ReO4– vs MoO42– for two redox-metallopolymers, poly(vinyl ferrocene) (PVFc) poly(3-ferrocenylpropyl methacrylamide) (PFPMAm) is evaluated. PVFc has a higher Re/Mo separation factor compared to PFPMAm 0.6 V Ag/AgCl. In techniques show that both swell the...
Abstract Ionene – ionic liquid (IL) composites are promising materials for CO 2 separation, yet a molecular‐level understanding of their structure and its impact on speciation, solubility, rotation, diffusivity remains unclear. Herein, using multimodal nuclear magnetic resonance (NMR), time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS), atomic force microscopy (AFM), molecular dynamics (MD) simulations, we reveal that the contain IL‐rich domains extending across hundreds nanometres...
Birds of a feather flock together: STM and DFT studies provide the first example spontaneous chiral resolution helicene on surface. Racemic 6,13-dicyano[7]helicene forms fully segregated domains pure enantiomers (2D conglomerate) Cu(111). The propensity system to optimize intermolecular CN⋅⋅⋅HC(Ar) hydrogen bonding CN⋅⋅⋅CN dipolar interactions translates into recognition with preferential assembly homochiral molecules. Detailed facts importance specialist readers are published as "Supporting...
Defects are unavoidable and usually originate exotic properties in realistic materials. One of the most fundamental defect-induced a solid surface is its reactivity to adsorbed species. anodes electrochemical cells for water splitting could therefore play critical role interatomic interactions at solvent/solid interfaces hence determining catalytic these Here, by means density-functional calculations PBE+U level, we investigate photo-oxidation on defective hematite(0001) substrates which...
Adopting the theoretical scheme developed by Nørskov group [see, for example, et al., J. Phys. Chem. B 108, 17886 (2004)], we conducted a density functional theory study of photo-driven oxidation processes water on various terminations clean hematite (α-Fe2O3) (0001) surface, explicitly taking into account strong correlation among 3d states iron through Hubbard U parameter. Six best-known terminations, namely, Fe−Fe−O3− (we call S1), O−Fe−Fe−(S2), O2−Fe−Fe−(S3), O3−Fe−Fe− (S4), Fe−O3−Fe−...
The high specific activity and cost-effectiveness of single-atom catalysts (SACs) hold great promise for numerous catalytic chemistries. In hydrogenation reactions, the mechanisms critical steps such as hydrogen activation spillover are far from understood. Here, we employ a combination scanning tunneling microscopy density functional theory to demonstrate that on model SAC comprised single Pd atoms Fe3O4(001), H2 dissociates heterolytically between surface oxygen. efficient allows...
A complete set of pseudopotentials and accompanying basis sets for all lanthanide elements are presented based on the relativistic, norm-conserving, separable, dual-space Gaussian-type pseudopotential protocol Goedecker, Teter, Hutter (GTH) within generalized gradient approximation (GGA) exchange–correlation functional Perdew, Burke, Ernzerhof (PBE). The corresponding have been molecularly optimized (MOLOPT) using a contracted form with single Gaussian exponents s, p, d states. f states...
Halogen bonding-based self-assembly of pyrene derivatives on Au(111).
Single-atom catalysis has been a topic of increasing interest due to the potential for improved selectivity, reactivity, and catalyst cost. However, single-atom catalysts are still difficult characterize under realistic reaction conditions, leading controversy regarding capabilities single atoms need model studies. Herein, we examine methanol on Pd supported Fe3O4(001) ultrahigh vacuum conditions. On Pd-free Fe3O4(001), small fraction is converted formaldehyde through methoxy intermediate at...
The hydrogenation of benzaldehyde to benzyl alcohol on carbon-supported metals in water, enabled by an external potential, is markedly promoted polarization the functional groups. presence polar co-adsorbates, such as substituted phenols, enhances rate aldehyde two effects, that is, polarizing carbonyl group and increasing probability forming a transition state for H addition. These effects enable route, which phenol acts conduit proton addition, with higher than direct transfer from...
Global optimization constitutes an important and fundamental problem in theoretical studies many chemical fields, such as catalysis, materials, or separations problems. In this paper, a novel algorithm has been developed for the global of large systems including neat ligated clusters gas phase supported periodic boundary conditions. The method is based on updated artificial bee colony (ABC) method, that allows adaptive-learning during search process. new tested against four classes diverse...