Ultrafine cobalt–ruthenium alloy on nitrogen and phosphorus co-doped graphene for electrocatalytic water splitting

Lacking inexpensive and efficiency-competitive alternatives to Pt-based electrocatalysts sets the main barrier for scalable generation of hydrogen from water splitting. Here we report an active and stable catalyst composed of ultrafine cobalt–ruthenium alloys on nitrogen and phosphorus co-doped graphene for hydrogen evolution. The nitrogen and phosphorus co-doping is beneficial for CoRu dispersion and contributes to boost the catalytic performance. Alloying cobalt with ruthenium resolves the challenge of simultaneously improving the intrinsic activity and active site density. The catalyst exhibits remarkable activity with low overpotential of 52 mV at 10 mA cm−2 and Tafel slope of 38 mV dec−1.