Revealing and magnifying interfacial effects between ruthenium and carbon supports for efficient hydrogen evolution

Ru has been considered as a highly efficient material for the hydrogen evolution reaction (HER) and becomes one of the promising alternatives to Pt owing to its relatively low price and similar hydrogen bonding strength. Carbon host materials, e.g., amorphous carbon (AC), porous carbon (PC), and ZIF-derived carbon (ZC), are widely used in Ru/C catalysts. Here, we investigate the influences of the above three different carbon host materials over the supported Ru species in Ru/C catalysts. A stronger metal-support interaction is revealed in the Ru/ZC catalyst, in which the supported Ru species are preserved in a metallic state and a highly dispersed form, resulting in enhanced HER activity and stability in alkaline media. Both the Ru sites and Ru-C interfacial sites are determined to be active for the HER in Ru/ZC according to our electrochemical poisoning experiment. In addition, an acid etching treatment (AET) strategy is proposed to magnify the interfacial effect of Ru/C catalysts for further HER improvement, and the optimal Ru/ZC-E50 catalyst that undergoes appropriate etching treatment shows a smaller Ru size and more exposed Ru-C interface, realizing an overpotential of only 29 mV (at 10 mA cm(-2)) and a Tafel slope of 82 mV dec(-1) that greatly outperform those of Ru-based and Pt-based materials for the HER in alkaline media. These specific findings can provide deeper insights into the design strategy, structure-property relationship, and future development of Ru/C catalysts for efficient HER.