Search

Reacting MoAlB with ZnCl2 at 550 °C produces metastable Mo2AlB2 through a one-step topochemical transformation. This reaction showcases differences in reactivity between boride-based MAB phases and carbide-based MAX phases, which are solid-state precursors to an important family of 2-D materials. [ABSTRACT FROM AUTHOR]

Data‐intensive discovery of water‐splitting catalysts can accelerate the development of sustainable energy technologies, such as the photocatalytic and/or electrocatalytic production of renewable hydrogen fuel. Through computational screening, 13 materials were recently predicted as potential water‐splitting photocatalysts: Cu3NbS4, CuYS2, SrCu2O2, CuGaO2, Na3BiO4, Sr2PbO4, LaCuOS, LaCuOSe, Na2TeO4, La4O4Se3, Cu2WS4, BaCu2O2, and CuAlO2. Herein, these materials are synthesized, their bandgaps and band alignments are experimentally determined, and their photoelectrocatalytic hydrogen evolution properties are assessed. Using cyclic voltammetry and chopped illumination experiments, 9 of the 13 materials are experimentally found to have bandgaps and band alignments that straddle the potentials required for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), as computationally predicted. During photocatalytic testing, 12 of the materials yield a measurable photocurrent. However, only three are found to be active for the HER, with Cu3NbS4, CuYS2, and Cu2WS4 producing H2 in amounts comparable to bare TiO2; a benchmark photocatalyst. This study provides experimental validation of computational bandgap and band alignment predictions while also successfully identifying active photocatalysts. [ABSTRACT FROM AUTHOR]

We report predictive guidelines for the substoichiometric cation exchange of model two-component metal sulfide nanorods containing divalent cations of similar hardness. Unit cell volume changes, cation radii, solubility constants, and solid state interfaces influence selectivity during substoichiometric exchange of Cu+ when multiple products are possible. [ABSTRACT FROM AUTHOR]

A newly developed robust strategy that utilizes shape- and size-controlled [beta]-Sn nanocrystals as reactive templates, is presented. The analysis helps in the production of various nanocrystals involving elements of notably different reduction potentials, reduction kinetics and reactivity.

A new low-temperature approach to the synthesis of atomically ordered nanocrystals using bimetallic nanoparticle precursors has been demonstrated. It is expected that approach to the synthesis of atomically ordered nanocrystals will be applicable to a wide range of inorganic solids, perhaps even yielding new metastable solids that are not stable in bulk systems.

High throughput theoretical methods are increasingly used to identify promising photocatalytic materials for hydrogen generation from water as a clean source of energy. While most promising water splitting candidates require co-catalyst loading and electrical biasing, computational costs to predict them a priori become large. It is, therefore, important to identify bare, bias-free semiconductor photocatalysts with small initial hydrogen production rates, often in the range of tens of nanomoles per hour, as these can become highly efficient with further co-catalyst loading and biasing. Here, we report a sensitive hydrogen detection system suitable for screening new photocatalysts. The hydrogen evolution rate of the prototypical rutile TiO2 loaded with 0.3 wt. % Pt is detected to be 78.0 ± 0.8 µmol/h/0.04 g, comparable with the rates reported in the literature. In contrast, sensitivity to an ultralow evolution rate of 11.4 ± 0.3 nmol/h/0.04 g is demonstrated for bare polycrystalline TiO2 without electrical bias. Two candidate photocatalysts, ZnFe2O4 (18.1 ± 0.2 nmol/h/0.04 g) and Ca2PbO4 (35.6 ± 0.5 nmol/h/0.04 g) without electrical bias or co-catalyst loading, are demonstrated to be potentially superior to bare TiO2. This work expands the techniques available for sensitive detection of photocatalytic processes toward much faster screening of new candidate photocatalytic materials in their bare state. [ABSTRACT FROM AUTHOR]

Topological materials have high carrier mobilities that can be maintained in the presence of crystal structure defects, which is useful for catalysis. Topological materials have been shown to be active catalysts, but it remains unclear if topology persists during catalysis. We studied the physical and chemical evolution of MoTe2 during photo‐ and electrocatalytic hydrogen production. This material offers a unique opportunity to directly compare a trivial semiconductor, 2H‐MoTe2, with a topological insulator, 1T'‐MoTe2, with comparable compositions, crystal structures, and surface roughnesses. We observed no major bulk changes in the materials after catalysis. The surfaces of the catalysts were significantly roughened and oxidized, but the carrier mobility of the topological phase remained high. These results suggest that topology persists during, and may be advantageous for, catalysis, and provide rationale for considering topology in the search for water‐splitting catalysts. [ABSTRACT FROM AUTHOR]