High mass-specific reactivity of a defect-enriched Ru electrocatalyst for hydrogen evolution in harsh alkaline and acidic media

Abstract

A reasonable design strategy to improve the utilization of noble metal electrocatalysts for the hydrogen evolution reaction (HER) is crucial to simplify the process flow and accelerate the future renewable energy economy. Here, abundant defects were created on 2.4-nm Ru nanoparticles to achieve unprecedently high mass-specific reactivity in harsh acidic and alkaline electrolytes. The obtained defect-enriched Ru (DR-Ru) exhibits an ultrahigh HER turnover frequency of 16.4 s−1 with a 100-mV overpotential in alkaline media, and it also retains an excellent value of 20.6 s−1 in acidic media; these results are superior to those reported for other Ru catalysts. Accordingly, a record-low loading of 2.5 µg cm−2 for the DR-Ru catalysts and low overpotentials of 28.2 and 25.1 mV at 10 mA cm−2 can be realized in alkaline and acidic media, respectively. Furthermore, the less coordinated Ru surface sites and partial lattice oxygen introduction weaken the bonding between H and DR-Ru catalysts, facilitate fast acidic HER kinetics and help dissociate the water molecule to overcome the major challenge of HER in alkaline electrolytes, leading to an activity comparable to that under acidic conditions. This result provides a guideline for defect engineering on noble metal nanocatalysts to effectively improve the utilization of the catalysts and optimize reactivities.