WO3-modified cobalt phosphide nanoflowers on nickel foam as an efficient bifunctional electrocatalyst for overall water splitting

Developing a highly efficient and cost-effective catalyst that promotes the hydrogen evolution reaction (HER) is a persistent and significant challenge. This study successfully constructed a WO 3 -modified cobalt phosphide nanoflower-like composite catalyst on nickel foam (CoP@WO 3 /NF) via a simple hydrothermal chemical reaction coupled with a low-temperature phosphidation process, which exhibit exceptional performance for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). For HER, a current density of 10 mA·cm-2 was achieved at an overpotential of 58 mV, with a corresponding Tafel slope of 73.78 mV·dec −1 . Under identical conditions, the catalyst required 302 mV for OER, accompanied by a Tafel slope of 113.9 mV·dec −1 . Additional evidence from EIS and double-layer capacitance tests confirmed its efficient charge transport and a sizable electrochemically active surface area. These findings present a viable approach for developing the bifunctional electrocatalysts composed of non-noble metals, which are highly applicable for electrochemical water splitting.