Ru doping and interface engineering synergistically boost the electrocatalytic performance of a WP/WP₂ nanosheet array for an efficient hydrogen evolution reaction

The surface electronic structure and morphology of catalysts have a crucial impact on the electrocatalytic hydrogen evolution reaction performance. This work reports on the fabrication of a Ru-doped WP/WP₂ heterojunction nanosheet array electrode via a one-step phosphating treatment of a Ru-doped WO₃ precursor. Benefitting from the large electrochemical active surface of nanosheet arrays, rich WP/WP₂ heterojunction interface, and trace Ru atom doping, the catalyst has a fairly low overpotential of 58.0 mV at 10 mA cm^-2 and a Tafel slope of 50.71 mV dec^-1 in acid solution toward the electrocatalytic HER. Further, theoretical calculations unveil that Ru atom doping and interface effect synergistically optimized the electronic structure of the catalyst and hence weakened the adsorption capacity of the catalyst surface toward hydrogen (H), which lowered the Gibbs free energy (ΔG_H*) and consequently effectively improved the HER performance. This work may open new avenues for developing advanced nanoarray electrodes with efficient electrochemical energy conversion.