In situ sacrificial CoMoO4 template to derive molybdenum-doped CoOOH nanosheets for alkaline hydrogen evolution reaction

Abstract

The fundamental insights into the dynamic structural variation of the electrocatalyst in the hydrogen evolution reaction (HER) are vital to the design of advanced HER electrocatalysts. However, their in-depth understanding is limited by the short lifespan of the intermediates and the transient structural changes. Here, we used in-situ, ex-situ, and computational technologies to investigate the dynamic reconstruction process of CoMoO4 nanosheets during the HER process and elucidate the relative HER mechanism. It turns out that the CoMoO4 species are spontaneously reconstructed into Mo-doped CoOOH nanosheets with optimized charge configuration during the HER process, and the interfacial water in the form of K+-H2O hydrated cations transfer the proton to the Co atom adjacent to the Mo atom determining the overall HER kinetics of Mo-doped CoOOH. The reconfigured HER electrocatalyst shows an overpotential of 37 mV at 10 mA cm−2, which is 15 mV higher than that of commercial Pt/C. © 2025