Ruthenium-doped cobalt sulphide electrocatalyst derived from a ruthenium–cobalt Prussian blue analogue (RuCo-PBA) for an enhanced hydrogen evolution reaction (HER)

RuCo-PBA-derived Ru-doped Co 9 S 8 nanosheets, i.e. Co 9 S 8 /Ru@48h, serve as excellent electrocatalysts for the hydrogen evolution reaction (HER), requiring only a small overpotential of 94 mV to deliver the benchmark current density of 10 mA cm −2 .