Interfacial engineering of Ni(OH)2 on W2C for remarkable alkaline hydrogen production

Abstract Promoting water dissociation kinetics and hydrogen desorption ability is the key challenge of tungsten carbides for boosting hydrogen evolution reaction (HER) in alkali environment. Here, we report that an interfacial engineered W2C–Ni(OH)2 electrocatalyst consisting of Ni(OH)2 layer-encapsulated W2C nanowire array can afford current densities of 10 and 100 mA cm−2 with overpotentials of only 60 and 213 mV in 1.0 M KOH, respectively, which not only surpasses the most previously reported W2C-based examples, but even outperforms the commercial Pt/C catalyst at high current densities. The experimental results based on the classic bifunctional mechanism suggest that Ni(OH)2 mainly acts as the scissors for the dissociation of water, and the W2C site serves as the location for the adsorption and desorption of hydrogen. Further density functional theory calculations reveal that the hybridization of W2C with Ni(OH)2 can also alleviate the strong tungsten hydrogen bond, further optimizing the hydrogen adsorption energy of the hybrid.