Self-Supported CoFe-P Nanosheets as a Bifunctional Catalyst for Overall Water Splitting

Highly efficient and stable dual-function electrocatalysts for overall water splitting are of great significance to promote the application of hydrogen energy. Constructing a bimetallic phosphide nanocomposite structure can enhance active sites and accelerate electron transfer, which is beneficial to electrocatalysis. Herein, we obtained self-supporting cobalt-iron phosphide nanosheets supported on foamed nickel through two-step hydrothermal and phosphating treatment. When the CoFe-P/NF-1 electrode material reaches 100 mA cm–2, only a HER overpotential of 180 mV is required. Moreover, the overpotential for OER is 275 mV at 200 mA cm–2. The overall water splitting electrolyzer assembled by CoFe-P/NF-1 can reach a current of 10 mA cm–2 at 1.57 V. The catalytic performance is better than the currently reported transition metal-based catalysts, and it exhibits excellent stability. This work provides a design idea of transition metal phosphide used in overall water splitting catalysis.