Cascade electrocatalysis via integration of ruthenium clusters and yttrium single atoms for a boosted alkaline hydrogen evolution reaction

Abstract

Anion-exchange-membrane water electrolysis (AEMWE) has emerged as a highly prospective technology for large-scale hydrogen production. However, its widespread application is severely restricted by the sluggish kinetics of the alkaline hydrogen evolution reaction (HER). Inspired by enzymatic cascade reactions, this work proposes a novel cascade electrocatalysis mechanism for the alkaline HER on a supported metal catalyst comprising Ru clusters and Y single atoms simultaneously immobilized on a N-doped carbon support (Ru–YNC). Specifically, oxophilic Y single atoms serve as preferential water adsorption and dissociation centers, and the generated hydrogen adsorption intermediates are promptly captured and reduced by adjacent Ru clusters owing to the different adsorption properties of Ru and Y species, thereby remarkably accelerating the alkaline HER kinetics. Consequently, the Ru–YNC exhibits an overpotential of only 22 mV at 10 mA cm⁻² in 1.0 M KOH. The assembled AEMWE electrolyzer delivers a current density of 1000 mA cm⁻² and a remarkable noble metal mass activity of 52.07 A mg_{noble metal}⁻¹ at a cell voltage of 1.87 V. Furthermore, it shows outstanding durability over 1000 h at 500 mA cm⁻² with a degradation rate of only 40 μV h⁻¹. This work provides new insights into catalyst design and mechanism exploration for the electrochemical alkaline HER.