High‐Entropy Sulfides as Highly Effective Catalysts for the Oxygen Evolution Reaction

Abstract

With respect to efficient use of diminishing or harder to reach energy resources, the catalysis of processes that will otherwise require high overpotentials is a very important application in today's world. As a newly developed class of materials, high‐entropy sulfides (HESs) are promising electrocatalysts for a variety of different reactions. In this report, HESs containing five or six transition metals are synthesized in a one‐step mechanochemical process. Seven HESs of Pnma (M:S≈1:1) and three Pa‐3 (M:S = 1:2) structures are investigated as electrocatalysts for the oxygen evolution reaction (OER). The performances and properties of the HESs with different compositions and structures are compared with each other and with commercial IrO2 as reference material, in terms of OER overpotential, Tafel slope, electrochemically active surface area, ionic conductivity, and durability. The structural and chemical properties of these HESs are determined by X‐ray diffraction, transmission electron microscopy, scanning electron microscopy, X‐ray photoelectron spectroscopy, and energy‐dispersive X‐ray spectroscopy. Most of the HESs show excellent and promising performance as OER electrocatalysts under alkaline conditions, and outperform the reference OER catalyst IrO2.

Synthesis, structure and electrochemical performance of an ultra-high-entropy rare earth orthoferrite (UHE REO) for overall water splitting (OWS)

“…Nevertheless, their widespread integration in renewable energy technologies is impeded by their exorbitant cost. 20–26 Consequently, substantial efforts have been directed towards designing and synthesizing electrocatalysts that utilize more cost-effective metals as viable alternatives for the OER and HER. In recent years, high-entropy materials (HEMs) have emerged as promising candidates for a new generation of catalysts, owing to their unique structural characteristics, elemental composition, and adaptive functional capabilities.…”

Phosphorus‐Modified Amorphous High‐Entropy CoFeNiCrMn Compound as High‐Performance Electrocatalyst for Hydrazine‐Assisted Water Electrolysis

“…[ 20–23 ] As unique emerging materials, the high‐entropy compounds such as alloy, oxides, carbides, phosphates, sulfides, and hydroxides, have been considered as ideal systems for designing advanced electrocatalysts due to their excellent stability, unique microstructure, and high catalytic activity. [ 21,24–28 ] Compared with electrocatalysts below ternary, high‐entropy materials have rich component modulation range and complex surface interface structure, which provides the possibility to achieve a nearly continuous distribution of adsorption energy curves. Non‐noble metal‐based high‐entropy compounds, such as CrMnFeCoNi consists of five elements with close radii or its derivatives, show promising application potentials in zinc–air battery, hydrogenation of p‐nitrophenol, solid‐state hydrogen storage, and water oxidation.…”