In situ O2-emission assisted synthesis of molybdenum carbide nanomaterials as an efficient electrocatalyst for hydrogen production in both acidic and alkaline media

We report here a unique in situ O-2-emission assisted synthesis method to prepare molybdenum carbide (MoxC) nanomaterials with dense active sites and high effective surface area. The key to this protocol is the delicate design and synthesis of polymeric hybrid precursors by taking advantage of the synergy among the reactants. Oxidative polymerization of aniline (ANI) to form polyaniline (PANI), which acted as the nitrogen-rich carbon source, was initiated by adding aqueous H2O2 instead of the conventionally used ammonium persulfate (APS), and phosphomolybdate anions (PMo12) were doped into the positively charged PANI matrix via coulombic interactions. During the polymerization, vigorous O-2 bubbles were in situ produced by H2O2 decomposition catalyzed by PMo12, which mechanically broke down the precursor into nanosized polymeric hybrids with a porous and loose morphology. The MoxC electrocatalyst was optimized by varying the feeding content of PMo12 and carbonization temperature, exhibiting remarkable catalytic activity and stability toward the hydrogen evolution reaction (HER) in both acidic and alkaline solutions. It requires an overpotential of only 144 mV and 141 mV to reach a current density of 10 mA cm(-2) in 0.5 M H2SO4 and in 1 M NaOH, respectively, making it among the best of the reported MoxC-based electrocatalysts.