Electronic Modulation and Mechanistic Study of Ru-Decorated Porous Cu-Rich Cuprous Oxide for Robust Alkaline Hydrogen Oxidation and Evolution Reactions

Abstract

Rational design of high-efficiency and viable electrocatalysts is essential in overcoming the bottleneck of sluggish alkaline hydrogen oxidation/evolution reaction (HOR/HER) kinetics. In this study, a metal-organic framework-derived strategy for constructing a Pt-free catalyst with Ru clusters anchored on porous Cu−Cu2O@C is proposed. The designed Ru/Cu−Cu2O@C exhibits superior HOR performance, with a mass activity of 2.7 mA (Formula presented.) at 50 mV, which is about 24 times higher than that of state-of-the-art Pt/C (0.11 mA (Formula presented.)). Significantly, Ru/Cu−Cu2O@C also displays impressive HER performance by generating 26 mV at 10 mA cm−2, which exceeds the majority of documented Ru-based electrocatalysts. Systematic characterization and density functional theory (DFT) calculations reveal that efficient electron transfer between Ru and Cu species results in an attenuated hydrogen binding energy (HBE) of Ru and an enhanced hydroxy binding energy (OHBE) of Cu2O, together with an optimized H2O adsorption energy with Cu2O as the H2O*-capturing site, which jointly facilitates HOR and HER kinetics.