Unlocking Interfacial Electron Transfer of Ruthenium Phosphides by Homologous Core-Shell Design toward Efficient Hydrogen Evolution and Oxidation.

Du, Hongfang; Du, Zhuzhu; Wang, Tingfeng; Li, Boxin; He, Song; Wang, Ke; Xie, Linghai; Ai, Wei et al. · Adv Mater · 2022

basic_science · Level V

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Abstract

Developing high-efficiency electrocatalysts for the hydrogen evolution and oxidation reactions (HER/HOR) in alkaline electrolytes is of critical importance for realizing renewable hydrogen technologies. Ruthenium phosphides (RuP<sub>x</sub> ) are promising candidates to substitute Pt-based electrodes; however, great challenges still remain in their electronic structure regulation for optimizing intermediate adsorption. Herein, it is reported that a homologous RuP@RuP<sub>2</sub> core-shell architecture constructed by a phosphatization-controlled phase-transformation strategy enables strong electron coupling for optimal intermediate adsorption by virtue of the emergent interfacial functionality. Density functional theory calculations show that the RuP core and RuP<sub>2</sub> shell present efficient electron transfer, leading to a close to thermoneutral hydrogen adsorption Gibbs free energy of 0.04 eV. Impressively, the resulting material exhibits superior HER/HOR activities in alkaline media, which outperform the benchmark Pt/C and are among the best reported bifunctional hydrogen electrocatalysts. The present work not only provides an efficient and cost-effective bifunctional hydrogen electrocatalyst, but also offers a new synthetic protocol to rationally synthesize homologous core-shell nanostructures for widespread applications.