Robust and Bifunctional Electrodeposited NiCoCr Ternary Alloy for Alkaline Water Electrolysis

Abstract

Electrodeposited NiCoCr ternary alloy is explored as a cost‐effective and Earth‐abundant alternative electrocatalyst for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline conditions. Different metal salt concentrations (between 10 and 100 mM) and cathodic current densities (between 75 and 225 mA cm−2) are tested to prepare an optimized material exhibiting both the best electrocatalytic efficiency and robustness for water splitting. Combining electrochemistry with complementary physicochemical characterizations (scanning electron microscopy, energy‐dispersive X‐ray spectroscopy analysis, and X‐ray photoelectron spectroscopy) has enabled to gain a deep knowledge of the composition, morphology, and catalytic activity before and after long‐term electrolytic tests. Compared with the related NiCo and NiCr binary alloys, NiCoCr shows catalytic performance for HER similar to NiCr and higher than that of NiCo. In contrast, its catalytic activity for OER is quite comparable to that of NiCo and higher than that of NiCr. Importantly, the presence of Cr is found to be beneficial to increase the oxidation resistance of the ternary alloy. This work provides a scalable way to produce bifunctional and robust electrode materials.