NiMo/CoP nanoflower electrodes with abundant heterogeneous interfaces as efficient electrocatalysts for alkaline water splitting

Abstract

The development of high-performance, excellent stability, and cost-effective non-precious metal catalysts is essential for large-scale electrochemical water splitting. In this study, we designed and constructed novel NiMo_X/CoP heterostructures with nanoflower morphology through hydrothermal, phosphorization, and magnetron sputtering processes, serving as efficient hydrogen and oxygen evolution reaction (HER and OER) catalysts. Electrochemical tests indicate the optimal sample NiMo₄₅₀/CoP exhibited excellent hydrogen evolution performance in an alkaline electrolyte, with overpotentials of only 30 and 215 mV at current densities of 10 and 100 mA cm⁻², respectively. Notably, the NiMo₄₅₀/CoP delivers outstanding long-term stability, maintaining 94 % of its initial performance over 60 h at a current density of 10 mA cm⁻². Furthermore, NiMo₄₅₀/CoP also demonstrated the lowest OER overpotential (216 mV at 10 mA cm⁻²), and the assembled two-electrode electrolyzer operated efficiently with a low cell voltage of 1.54 V. The excellent catalytic performance and stability may be attributed to the synergistic effect of NiMo alloy and the layered heterostructure of NiMo_X/CoP. This research outlines a method for preparing high-activity non-precious metal catalysts, which has the potential to promote industrial water splitting applications.