A Novel Bimetallic Nickel–Molybdenum Carbide Nanowire Array for Efficient Hydrogen Evolution

The design and fabrication of noble‐metal‐free hydrogenevolution electrocatalysts with high activity is significant to future renewable energy systems. In this work, self‐supported NiMo carbide nanowires on carbon cloth (Ni 3 Mo 3 C@NPC NWs/CC; NPC=N,P‐doped carbon) were developed through an electropolymerization‐assisted procedure. During the synthesis process, NiMoO 4 nanowires were first grown on CC through a hydrothermal reaction that was free of any polymer binder such as Nafion. By use of electropolymerization, the as‐prepared NiMoO 4 NWs/CC sample was then coated by a layer of polypyrole (PPy) that served as the carbon source for subsequent conversion into Ni 3 Mo 3 C@NPC NWs/CC by carbothermal reduction. The experimental results indicated that judicious choices of the amount of coated PPy and the pyrolysis temperature were essential for obtaining the pure‐phase, nanowire array structure of Ni 3 Mo 3 C@NPC NWs/CC. Benefitting from the pure phase of the bimetallic carbide, the unique architecture of the nanowire array, and its self‐supported nature, the optimized Ni 3 Mo 3 C@NPC NWs/CC electrode exhibited excellent performance in the hydrogen evolution reaction (HER) in both acidic and alkaline media. Low overpotentials of 161 and 215 mV were required to afford a high current density of 100 mA cm −2 toward the HER in acidic and alkaline media, respectively, and the catalytic activity was maintained for at least 48 h, which puts Ni 3 Mo 3 C@NPC NWs/CC among the best HER electrocatalysts based on metallic carbides yet reported.