Three-dimensional porous Co-P alloy supported on copper foam as a new catalyst for sodium borohydride electrooxidation

Cobalt has been extensively studied as an effective catalyst for electrooxidation of sodium borohydride. However, there is still a problem of low catalytic activity for cobalt catalysts. How to improve the catalytic activity of cobalt for electrooxidation of sodium borohydride has become a challenge. In this paper, a novel catalyst Co-P alloy is supported on copper foam (CF) substrate by a one-step electrodeposition method. In the electrodeposition process, a Co-P/CF electrode with a three-dimensional (3D) porous structure was successfully prepared by using hydrogen bubbles as a dynamic template. Through the physical characterization of Co-P/CF, it is proved that the doping of P element produced more Co clusters on the surface of the electrode, which results in more active sites. These characteristics are very beneficial to NaBH4 electrooxidation. The electrochemical characterization confirmed that the electrocatalytic activity of Co-P/CF for NaBH4 was better than Co/CF. At room temperature, the Co-P/CF in 2.0 mol dm-3 NaOH + 0.20 mol dm-3 NaBH4 solution, the oxidation current density reached 1795 mA cm-2 at -0.20 V (vs. Ag/AgCl), which is higher than previously reported in the literatures.