Tungsten diphosphide nanorods as an efficient catalyst for electrochemical hydrogen evolution

A novel tungsten diphosphide nanorods (WP2 NRs) material with good crystallinity is synthesized as an efficient hydrogen evolution reaction (HER) electrocatalyst for the first time through phosphidation of (NH4)0.25WO3 NRs precursor. Towards HER the WP2 NRs exhibit an onset overpotential of 56 mV, a Tafel slope of 52 mV per decade and an exchange current density of 0.013 mA cm−2 in acidic media. Further, the catalyst only needs overpotentials of 101 and 148 mV to deliver current densities of 2 and 10 mA cm−2, respectively. In particular, the catalyst can maintain its catalytic activity for 90 h at least, showing good long term operation stability. It also has excellent activity and stability under both neutral and basic conditions. The catalysis mechanism of WP2 NRs is explored for the fundamental insights.