A5006222293- Nanopore and Nanochannel Transport Studies
- Spectroscopy and Quantum Chemical Studies
- Membrane-based Ion Separation Techniques
- Machine Learning in Materials Science
- Electrochemical Analysis and Applications
- Semiconductor materials and devices
- Ga2O3 and related materials
- Fuel Cells and Related Materials
- Electrocatalysts for Energy Conversion
- Electronic and Structural Properties of Oxides
- Electrostatics and Colloid Interactions
- Advanced Chemical Physics Studies
- Nanowire Synthesis and Applications
- X-ray Diffraction in Crystallography
- Advancements in Battery Materials
- Graphene research and applications
- Gas Sensing Nanomaterials and Sensors
- Ionic liquids properties and applications
- Electron and X-Ray Spectroscopy Techniques
- Carbon Nanotubes in Composites
- Biofuel production and bioconversion
- ZnO doping and properties
- Quantum, superfluid, helium dynamics
- Supercapacitor Materials and Fabrication
- Quantum Dots Synthesis And Properties
Lawrence Livermore National Laboratory
2016-2025
Quantum Simulations (United States)
2015-2025
Institute for the Future
2025
Michigan State University
2023-2024
University of California, Irvine
2024
City University of New York
2024
Columbia University
2024
National Renewable Energy Laboratory
2024
Materials and Electrochemical Research (United States)
2024
Griffith University
2021-2023
Fast water transport through carbon nanotube pores has raised the possibility to use them in next generation of treatment technologies. We report that permeability 0.8-nanometer-diameter porins (CNTPs), which confine down a single-file chain, exceeds biological transporters and wider CNT by an order magnitude. Intermolecular hydrogen-bond rearrangement, required for entry into nanotube, dominates energy barrier can be manipulated enhance rates. CNTPs block anion transport, even at salinities...
State-of-the-art desalination membranes exhibit high water-salt selectivity, but their ability to discriminate between ions is limited. Elucidating the fundamental mechanisms underlying ion transport and selectivity in subnanometer pores therefore imperative for development of ion-selective membranes. Here, we compare overall energy barrier salt barriers individual transport, showing that cations anions traverse membrane pore an independent manner. Supported by density functional theory...
The development of sodium and potassium batteries offers a promising way to meet the scaling cost challenges energy storage. However, compared Li+, several intrinsic properties Na+ K+, including their solvation dynamics in typical organic electrolytes utilized battery applications, are less well-understood. Here, we report systematic investigation K+ ethylene carbonate (EC) using first-principles molecular simulations. Our simulations reveal significant differences structure dynamical Li+....
Nitrate is a ubiquitous aqueous pollutant from agricultural and industrial activities. At the same time, conversion of nitrate to ammonia provides an attractive solution for coupled environmental energy challenge underlying nitrogen cycle, by valorizing carbon-free carrier essential chemical feedstock. Mass transport limitations are key obstacle efficient water streams, due dilute concentration nitrate. Here, we develop bifunctional electrodes that couple nitrate-selective...
Machine learning unveils molecular transport mechanisms obscured by entropy-enthalpy compensation in polymeric membranes.
Abstract Machine learning interatomic potentials (MLIPs) enable accurate simulations of materials at scales beyond that accessible by ab initio methods and play an increasingly important role in the study design materials. However, MLIPs are only as robust data on which they trained. Here, we present DImensionality-Reduced Encoded Clusters with sTratified (DIRECT) sampling approach to select a training set structures from large complex configuration space. By applying DIRECT Materials...
Abstract We report a newly synthesized inorganic polymer photoresist with high ceramic yield by the functionalization of polyvinylsilazane (KiON VL20) 2‐isocyanatoethyl methacrylate via linkage or insertion reaction routes. The chemistry synthesis and pyrolytic conversion as well mechanical evaluation were investigated using various analytical instruments. show for first time that this photosensitive resin is novel precursor fabrication complex 3D SiCN microstructures 210 nm resolution...
The contamination of water resources with nitrate is a growing and significant problem. Here we report the use ultramicroporous carbon as capacitive deionization (CDI) electrode for selectively removing from an anion mixture. Through moderate activation, achieve micropore-size distribution consisting almost exclusively narrow (<1 nm) pores that are well suited adsorbing planar, weakly hydrated molecule. Cyclic voltammetry measurements reveal enhanced capacitance when compared to chloride ion...
Abstract Understanding redox and photochemical reactions in aqueous environments requires a precise knowledge of the ionization potential electron affinity liquid water. The former has been measured, but not latter. We predict water its surface from first principles, coupling path-integral molecular dynamics with ab initio potentials, many-body perturbation theory. Our results for (0.8 eV) agree well recent pump-probe spectroscopy measurements on amorphous ice. Those bulk (0.1–0.3 differ...
In a recent paper [Nguyen et al., Phys. Rev. B 85, 081101(R) (2012)] we presented an approach to evaluate quasiparticle energies based on the spectral decomposition of static dielectric matrix. This method does not require calculation unoccupied electronic states or direct diagonalization large matrices, and it avoids use plasmon-pole models. The numerical accuracy is controlled by single parameter, i.e., number eigenvectors used in Here present comprehensive validation method, encompassing...
We present an approach to evaluate quasiparticle energies within many-body perturbation theory that substantially improves both the computational efficiency and numerical accuracy of existing techniques. use eigenvectors static dielectric matrix as a basis for frequency-dependent density-density response function, density functional avoid explicit calculation empty electronic states, storage inversion large matrices. The our is controlled by single parameter can be systematically varied test...
Establishing an accurate and predictive computational framework for the description of complex aqueous solutions is ongoing challenge density functional theory based first-principles molecular dynamics (FPMD) simulations. In this context, important advances have been made in recent years, including development sophisticated exchange-correlation functionals. On other hand, simulations on simple generalized gradient approximation (GGA) functionals remain active field, particularly study due to...
Small diameter carbon nanotubes show high water-salt permselectivity and low activation barrier for water transport.
The oxygen-evolution reaction (OER) is pivotal in many energy-conversion technologies as it an important counter to others that convert stable chemicals higher-value products using electrochemistry. local microenvironment and pH for the anode OER can vary from acidic neutral alkaline depending on system being explored, making definitive mechanistic insights difficult. In this paper, we couple experiments, first-principles calculations based density functional theory, microkinetics, transport...
Abstract Improved understanding of aqueous solutions at graphitic interfaces is critical for energy storage and water desalination. However, many mechanistic details remain unclear, including how interfacial structure response are dictated by intrinsic properties solvated ions under applied voltage. In this work, we combine hybrid first-principles/continuum simulations with electrochemical measurements to investigate adsorption several alkali-metal cations the interface graphene within...
Titanium (Ti) and its alloys are attractive for a wide variety of structural functional applications owing to excellent specific strength, toughness stiffness, corrosion resistance. However, if exposed hydrogen sources, these susceptible hydride formation in the form TiHx (0 < x ≤ 2), leading crack initiation mechanical failure due lattice deformation stress accumulation. The kinetics hydriding process depends on several factors, including critical saturation threshold within Ti, interaction...
Light-driven hydrogen generation from water is a route to carbon-neutral fuels. However, the integrated light absorbers and catalysts must be compatible functional under same conditions. A sulfate-functionalized complex, [Ni(H2O)(7-PPh2NArSO3)2](NaBF4), where PPh2NArSO3 = 4-(3,6-diphenyl-1,3,6-azadiphosphepan-1-yl)benzenesulfonate), was synthesized characterized. solid-state structure single-crystal X-ray crystallography also reported. The electrocatalytic activity for evolution of this...
Spores of Aspergillus sp. SU14 were treated repeatedly and sequentially with Co(60) γ-rays, ultraviolet irradiation, N-methyl-N'-nitro-N-nitrosoguanidine. One selected mutant strain, SU14-M15, produced cellulase in a yield 2.2-fold exceeding that the wild type. Optimal conditions for production by fungal strain using solid-state fermentation examined. The medium consisted wheat-bran supplemented 1% (w/w) urea or NH(4)Cl, rice starch, 2.5 mM MgCl(2), 0.05% (v/w) Tween 80. moisture content...
By combining ab initio molecular dynamics simulations and many-body perturbation theory calculations of electronic energy levels, we determined the band edge positions functionalized Si(111) surfaces in presence liquid water, with respect to vacuum water redox potentials. We considered surface terminations commonly used for Si photoelectrodes splitting experiments. found that, when exposed semiconductor edges were shifted by approximately 0.5 eV case hydrophobic surfaces, irrespective...