Co&Mo bimetallic oxides derived from polyoxometalates (CoMo₆) towards hydrogen evolution reaction

Engineering platinum-free catalysts with high activity and stability is essential for electrocatalytic hydrogen evolution reaction (HER). In this work, polyoxometalates-derived Mo-based oxide materials Co-Mo₄O₁₁-MoO₂/rGO@X (abbreviated as Co-MoO/rGO@X, where X represents the synthesis temperature of 300, 400, 500 and 600 °C) were designed and synthesized on a nickel foam for HER under alkaline conditions. The Co-MoO/rGO@500 sample exhibited excellent HER catalytic activity, including an overpotential of 42 mV at a current density of 10 mA cm⁻², a Tafel slope of 85.6 mV dec⁻¹, and excellent long-term stability, due to its high intrinsic activity and superior conductivity. The layered structure of the Co-MoO/rGO@500 reveals a greater number of active sites and provides an abundant supply of oxygen vacancies, which significantly enhance the electrocatalytic activity. The incorporation of cobalt-doped molybdenum oxide in this study, along with the introduction of reduced graphene oxide (rGO), synergistically enhances the HER properties.