In Situ Fabrication of Tungsten Diphosphide Nanoparticles on Tungsten foil: A Hydrogen-Evolution Cathode for a Wide pH Range

Identifying non-precious metal electrocatalysts for the hydrogen-evolution reaction (HER) with high efficiency and stability is a considerable challenge for the hydrogen-based energy industry. We report the preparation of WP₂ nanoparticles supported on W foil (WP₂ NPs/W) through phosphidation of the corresponding WO₃ NPs/W precursor. This hydrogen evolution cathode shows a high HER catalytic activity with a low overpotential (j>100 mA cm⁻² at η=211 mV), a small Tafel slope (66 mV dec⁻¹), and a large exchange current density (0.09 mA cm⁻²) as well as excellent stability over 27 h in acidic solution. Notably, this catalyst also offers superior catalytic activity and remarkable stability under neutral and alkaline conditions. It is worth noting that, as a Pt-free HER catalyst, WP₂ NPs/W shows an electrocatalytic activity comparable to reported noble metal-free HER electrocatalysts at all pH values. Thus, the in situ conversion method provides a pathway to fabricate highly efficient and low-cost as well as self-supported non-precious-metal electrodes for HER.