Binder-free CuCo electrodeposited onto nickel foam for bifunctional alkaline water splitting

High-active and low-cost bifunctional electrocatalysts are required for sustainable alkaline water-splitting. In this work, a CuCo-based catalyst was directly electrodeposited onto nickel foam (NF) and assessed for the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and overall water splitting (OWS) using 1 M KOH. The coexistence of surface Cu and Co species with mixed chemical states was identified by XPS. NF–CuCo exhibited the highest bifunctional activity compared with bare NF and monometallic NF–Cu, NF–Co, NF–Fe, and NF–Sn electrodes. It required 64 mV for HER and 203 mV for OER to deliver 50 mA cm −2 . The NF–CuCo||NF–CuCo electrolyzer achieved 50 mA cm −2 at approximately 1.82 V and sustained stable performance for 12 h at 100 mA cm −2 . The enhanced performance is associated with the combined presence of Cu and Co components, favorable interfacial charge-transfer kinetics, and the multivalent surface chemistry of the electrode.