Aloysius Soon

Single-atom catalysts (SACs) provide an ideal platform for reducing noble-metal usage. SACs also exhibit unusual catalytic properties due to the absence of a metal surface. The role of the support may have a significant effect on the catalytic properties, similar to that of the ligand molecules in homogeneous catalysts. Here, the support effect was demonstrated by preparing a single-atom platinum catalyst on two different supports: titanium carbide (Pt1/TiC) and titanium nitride (Pt1/TiN). The f

To obtain insight into the structure and surface stoichiometry of copper-based catalysts in commercially important chemical reactions such as the oxygen-assisted water-gas shift reaction, we perform density-functional theory calculations to investigate the relative stability of low-index copper oxide surfaces. By employing the technique of ``ab initio atomistic thermodynamics,'' we identify low-energy surface structures that are most stable under realistic catalytic conditions are found to exhib

As a first step towards gaining microscopic understanding of copper-based catalysts, e.g., for the low-temperature water-gas shift reaction and methanol oxidation reactions, we present density-functional theory calculations investigating the chemisorption of oxygen, and the stability of surface oxides on $\mathrm{Cu}(111)$. We report atomic geometries, binding energies, and electronic properties for a wide range of oxygen coverages, in addition to the properties of bulk copper oxide. Through cal

Native defects in cuprous oxide ${\text{Cu}}_{2}\text{O}$ are investigated by using first-principles calculations based on density-functional theory. Considering the formation of copper and oxygen vacancies, antisites and interstitials, and a copper split-vacancy complex defect, we analyze the electronic structure and calculate their respective formation energies as a function of the change in Fermi level under both copper-rich and oxygen-rich conditions. We find that, under both growth conditio

High Resolution Image Download MS PowerPoint Slide CsSnI 3 is a potential lead-free inorganic perovskite for solar energy applications due to its nontoxicity and attractive optoelectronic properties. Despite these advantages, photovoltaic cells using CsSnI 3 have not been successful to date, in part due to low stability. We demonstrate how gradual substitution of Rb for Cs influences the structural, thermodynamic, and electronic properties on the basis of first-principles density functional theo

Abstract To date, the search for active, selective, and stable electrocatalysts for the oxygen evolution reaction (OER) has not ceased and a detailed atomic-level design of the OER catalyst remains an outstanding (if not, compelling) problem. Considerable studies on different surfaces and polymorphs of iridium oxides (with varying stoichiometries and dopants) have emerged over the years, showing much higher OER activity than the conventionally reported rutile-type IrO 2 . Here, we have considere

As a first step towards a microscopic understanding of single-Pt atom-dispersed catalysts on non-conventional TiN supports, we present density-functional theory (DFT) calculations to investigate the adsorption properties of Pt atoms on the pristine TiN(100) surface, as well as the dominant influence of surface defects on the thermodynamic stability of platinized TiN. Optimized atomic geometries, energetics, and analysis of the electronic structure of the Pt/TiN system are reported for various su

In an attempt to promote energy saving through the clever control of varying amounts of visible light and solar energy in modern buildings, there has been a surge of interest in the novel design of multifunctional glass windows otherwise known as “smart windows”. The use of chromogenic materials (e.g., tungsten oxides and their alloys) is widespread in this cooling energy technology, and for the case of hexagonal tungsten oxide (h-WO 3 )-based systems, the overall efficiency is often hindered by

The ternary chalcogenide, ZnIn2S4, is known to exhibit various polymorphic expressions: from the cubic spinel phase to various polytypic layered hexagonal structures, commonly known as α, β, IIa, and IIb. Notwithstanding numerous recent studies on the superior photocatalytic activities of hexagonal ZnIn2S4, it remains unclear how the polymorphic expressions in this material may influence its physiochemical properties (and thus their performance in actual photodevices). Thus, revisiting and addre

Controlling the stoichiometry and metastability in functional oxides is often the key to enhance their performance for a range of important oxide-based technological applications. In this work, using the recently developed meta-generalized-gradient approximation (GGA) and hybrid density functional theory calculations, we study both stoichiometric and substoichiometric (Magnéli) oxides of tungsten and molybdenum, focusing on their structural parameters, growth thermodynamics, and electronic struc

Using first-principles density-functional theory calculations, we investigate the advantage of using h-WO₃(and its surfaces) over the larger band gap γ-WO₃phase for the anode in water splitting. We demonstrate that h-WO₃is a good alternative anode material for optimal water splitting efficiencies.