Robust hydrogen evolution reaction catalysis by ultrasmall amorphous ruthenium phosphide nanoparticles.

Here, we report a facile method to synthesize ruthenium phosphides with diameter 1 nm and an amorphous structure at room temperature. Only 31 mV vs. RHE overpotential is required to deliver 10 mA cm-2 and no degradation in hydrogen evolution reaction (HER) performance is recorded after 24 h of catalysis at 100 mA cm-2.