Synthesis of nickel phosphate nanowires as a bifunctional catalyst for water electrolysis in alkaline media

Abstract

The electrocatalytic water splitting (WS) process for hydrogen (H2) and oxygen (O2) production is known for its high efficiency, necessitating the development of bifunctional electrode materials. These materials must possess strong catalytic activity, significant active sites, high stability, and an abundance of earth-friendly components to ensure efficient and prolonged H2 and O2 generation. In this study, we employed a hydrothermal method to synthesize unique one-dimensional (1D) nickel phosphate (NiPO) nanoneedles directly grown on nickel foam (NF). The in-situ synthesis of the NiPO/NF catalyst offers favorable streamlining, facilitating electrode production and improving the contact between active sites and the conductive substrate. Under alkaline conditions, the NiPO/NF electrodes demonstrated low overpotentials of 374 mV and 377 mV at a high current density (J) of 250 mAcm−2 for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively. These values indicate efficient and stable electrocatalytic activity. Moreover, the NiPO/NF catalyst exhibited continuous bifunctional catalytic activity for 12 hours with a J exceeding 20 mAcm−2. These findings suggest that NiPO/NF has the potential to be a cost-effective and sustainable option for large-scale WS applications.