Two‐Dimensional Amorphous Cr2O3 Modified Metallic Electrodes for Hydrogen Evolution Reaction

Abstract

The surface modification of benchmarked metal catalysts using nanostructured non‐metallic materials for improved performance and stability is an active area of research and is interesting from both a fundamental and an applied perspective. Amorphous few layered nanosheets of Cr2O3 (3–5 nm) are synthesized by rapid thermal exfoliation of CrCl3 · 6H2O precursors and are characterized. The hydrogen evolution reaction (HER) studies on alkaline medium conducted with platinum and gold electrodes modified with amorphous sheets of Cr2O3 show augmented HER activity compared to the pristine ones while Cr2O3 alone is not HER active. The role of amorphous Cr2O3 as a co‐catalyst is established and the synergistic charge transfer effects while coupling Cr2O3 with metal catalysts are studied using electrochemical impedance spectroscopy. Large‐scale processability of amorphous Cr2O3 by rapid thermal treatment along with its high electrochemical stability (>2000 cycles or >50 h) in harsh alkaline conditions, where benchmarked metals fail, open new avenues in designing novel scalable catalysts by protecting the surface of noble metal catalysts without sacrificing the electrochemical performance.