Electrodeposited Copper-Cobalt-Phosphide: A Stable Bifunctional Catalyst for Both Hydrogen and Oxygen Evolution Reactions

Developing earth abundant catalysts for clean energy technologies is vital to address the issues related to the use of fossil fuels and associated pollution, which adversely affects human health. Herein, we report an electrochemically deposited mixed Cu-Co-P film, as a bifunctional catalyst with high stability and activity for the hydrogen evolution reaction (HER, in 0.5 M H2SO4 and 1 M KOH) and the oxygen evolution reaction (OER, in 1 M KOH). In alkaline medium, the Cu-Co-P catalyst outperforms the state-of-art catalysts for both HER (Pt) and OER (RuO2) and is stable under continuous electrolysis for up to 72 hours. Using Cu-Co-P electrodes as both the anode and the cathode increases the activity by similar to 2.5 times greater than the integrated performance of RuO2 (anode) and Pt (cathode) at 1.9 V. The competent bifunctionality of Cu-Co-P is facilitated by Cu incorporation, leading to a low surface passivation of the electrode. This study offers a new strategy to develop earth abundant bimetallic phosphides, which are potential catalysts for many alternative energy technologies.