Vanadium Oxide Clusters Decorated Metallic Cobalt Catalyst for Active Alkaline Hydrogen Evolution

Promoting active and stable H2 evolution reaction (HER) on metallic Fe triad materials is important yet challenging. Here, we report a metallic Co catalyst modulated by vanadium oxide (VOx) clusters (denoted as Co(VOx)) for active alkaline HER activity. Systematic X-ray absorption spectroscopy (XAS) and X-ray crystallography studies verify that VOx clusters endow Co with a highly disordered lattice and downsized particle size. The best Co(VOx) electrode is achieved with an optimal doping level of 3%, which delivers −100 mA cm−2 at an overpotential merely of 178 mV, in contrast to 344 mV and continuous activity decay on pure Co. The lower or higher doping level is unable either to regulate the atomic structure and reduce the H binding or to provide fewer active sites. Density functional theory (DFT) calculations reveal that VOx enables efficient electron transfer from Co to VOx, thus decreasing the H-adsorption on V-Co(001) for enhanced HER.