Recording the Pt-beyond hydrogen production electrocatalysis by dirhodium phosphide with an overpotential of only 4.3 mV in alkaline electrolyte

The innovation for efficient water electrolysis catalysts and the manner for boosting the multistep reaction are highly demanded for hydrogen economy. In this study, P-defected Rh2P nanoparticles have been prepared through pyrolysis of Rh-organic complex under a reductive atmosphere, showing enjoyable HER performances under both acidic and alkaline electrolytes. Especially in alkaline HER, P-defected Rh2P shows the lowest overpotential of 4.3 mV at 10 mA cm−2, outperforming the Pt/C benchmark. First-principle calculations are further conducted to elucidate the rationales behind. The calculations revealed that P-defected Rh2P nanoparticles have the nearest H adsorption sites distance (3.94 Å to 1.98 Å) and lowest activation barrier (1.39 eV to 0.786 eV) compared with Rh2P, promoting the subsequent H2 release. The study provides valuable insights into the rational design of advanced HER electrocatalysts as well as the mechanism comprehension from the neighbored Had distance as an alternative dynamic HER descriptor.