Hierarchical phosphorus-doped CoMoO4-x nanoarrays accelerate the water dissociation for efficient hydrogen evolution under alkaline electrolyte

The electrolysis of water splitting is a critical technology to produce the hydrogen by green electricity. The design of highly efficient, low-cost, and stable electrocatalysts is the important point in this process. The structure modification by doping is concerned intensively because it optimizes the electronic conductivity and the absorption of reaction intermediates. The transition metal oxides are the efficient catalysts for water splitting under the alkaline electrolyte. However, the limited structure and number of surficial sites restrict the electrochemical activity. In this work, the phosphorus-doped CoMoO 4- x nanosheets on CoO nanowire (CoMoO 4-x P x /CoO) is developed as one efficient hydrogen evolution reaction (HER) electrocatalyst in alkaline media. The optimized CoMoO 4-x P x /CoO shows a small overpotential of 63 mV at 10 mA cm −2 for the HER in 1 M KOH. Combined characterization and density functional theory calculation, the active sites of CoMoO 4-x P x /CoO for HER are the surficial Co and Mo atoms that are linked by a P-OH structure.