Electrodeposited Ni−Co−P Triple-Layered Structure as A Robust and Durable Electrocatalyst for Hydrogen Evolution

Designing Earth-abundant, cost-effective catalysts for hydrogen evolution via water splitting is essential for hydrogen generation. Adding a third metal element to binary phosphides provides the opportunity to tune their morphology, crystalline and electronic structures and thus their electrocatalytic properties. In this study, a hierarchical crystalline/amorphous Ni−Co−P compound is prepared on nickel foam (NF) with different nickel to cobalt ratio by one-step electrodepositing technique. The Ni−Co−P/NF is composed of metallic Co and amorphous phosphides. It has hierarchical morphology, consisting of ∼800 nm spherical particles in the bottom layer, ∼1.5 μm spherical particles in the middle layer, and staggered network structure on the top layer. The Ni−Co−P/NF electrode exhibits superior hydrogen evolution reaction (HER) catalytic activity in the alkaline solution, which requires only 72 mV for delivering 10 mA cm−2. More importantly, the Ni−Co−P/NF catalyst sustains the current density of 20 mAcm−2 for 53 h with negligible degradation in overpotential which shows remarkable electrochemical stability.