Tensile-strained ruthenium phosphide by anion substitution for highly active and durable hydrogen evolution

Abstract Exploiting cost-effective, efficient and durable electrocatalysts toward hydrogen evolution reaction (HER) is of significant importance for the widespread application of water electrolyzers. Although ruthenium phosphide (RuP) has been hailed as a highly promising candidate, considerable performance disparity still lies between RuP and mainstream Pt/C benchmark, which calls for the structural regulation on RuP at molecular scale. Herein, for the first time, we develop a simple anion substitution strategy to obtain favorable strain regulation on RuP catalyst toward enhanced HER activity. The tensile strain enables an upshift of the d-orbital energy level of Ru site, facilitating hydrogen adsorption as well as water dissociation to accelerate the HER kinetics. Impressively, the as-developed N–RuP/NPC catalyst not only outperforms most of the reported Pt-free catalysts, showing record-high turnover frequencies of 1.56 H2 s−1 and 0.72 H2 s−1 at an overpotential of 30 mV in acidic and alkaline electrolyte, respectively, but also surpasses the Pt/C benchmark with a significantly smaller overpotential (58.9 mV vs 73.1 mV in acidic electrolyte) at a large current density of 100 mA cm−2. Beyond that, such atomic level regulation also suppresses the electrochemical reconstruction and thereby guarantees superior durability over 10000 cycles.