High-performance self-supporting AgCoPO4/CFP for hydrogen evolution reaction under alkaline conditions

Abstract

Electrochemical water decomposition to produce hydrogen is a promising approach for renewable energy storage. It is vital to develop a catalyst with low overpotential, low cost and high stability for hydrogen evolution reaction (HER) under alkaline conditions. Herein, we used a simple hydrothermal method to obtain a AgCo(CO)₄ precursor on the surface of carbon fiber paper (CFP). After thermal phosphorization, the self-supporting catalyst AgCoPO₄/CFP was obtained, which greatly improved the HER catalytic performance under alkaline conditions. At 10 mA cm⁻², it showed an overpotential of 32 mV. The Tafel slope was 34.4 mV dec⁻¹. The high catalytic performance of AgCoPO₄/CFP may be due to the hydrophilic surface promoting effective contact with the electrolyte and the synergistic effect of the two metals, which accelerated electron transfer and thus promoted hydrogen evolution reaction. In addition, it showed an outstanding urea oxidation reaction (UOR) activity. After adding 0.5 M urea, the over-potential of the AgCoPO₄/CFP assembled electrolytic cell was only 1.45 V when the current density reached 10 mA cm⁻², which was much lower than that required for overall water splitting. This work provides a new method for the design and synthesis of efficient HER electrocatalysts.