Electrodeposition of copper-cobalt bimetallic phosphide on nickel foam as an efficient catalyst for overall water splitting

Abstract

The application of non-precious metal bifunctional electrode materials is relevant to solving the current serious energy and environmental problems. In this study, the Cu-Co-P/NF bifunctional electrocatalyst with grape-like clusters was successfully prepared for water splitting using nickel foam (NF) as a substrate by electrodeposition. In alkaline conditions, the catalysts showed good catalytic activity and stability in both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). At 10 mA cm-2, the overpotential required for HER was only 64 mV, whereas for OER it was 334 mV, with Tafel slopes of 40 mV dec-1 and 74 mVdec-1, respectively, and almost negligible potential fluctuations after 49 h and 52 h of testing under continuous electrolysis. Furthermore, the two-electrode electrolyzer required only 1.55 V to achieve 10 mA cm-2 in 1 M KOH solution when Cu-Co-P/NF was used as both cathode and anode for water splitting, which was superior to most previously reported electrocatalysts, and it also showed good durability in a 82 h test. Therefore, it has promising applications in industrial electrolytic systems. The unusual Cu-Co-P/NF with grape-like clusters, as well as the synergistic effect between Co and Cu atoms and the high electrochemically active surface area (ECSA), are responsible for the remarkable catalytic performance.