Active Sites Intercalated Ultrathin Carbon Sheath on Nanowire Arrays as Integrated Core–Shell Architecture: Highly Efficient and Durable Electrocatalysts for Overall Water Splitting

Abstract The development of active bifunctional electrocatalysts with low cost and earth‐abundance toward oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) remains a great challenge for overall water splitting. Herein, metallic Ni 4 Mo nanoalloys are firstly implanted on the surface of NiMoO x nanowires array (NiMo/NiMoO x ) as metal/metal oxides hybrid. Inspired by the superiority of carbon conductivity, an ultrathin nitrogen‐doped carbon sheath intercalated NiMo/NiMoO x (NC/NiMo/NiMoO x ) nanowires as integrated core–shell architecture are constructed. The integrated NC/NiMo/NiMoO x array exhibits an overpotential of 29 mV at 10 mA cm −2 and a low Tafel slope of 46 mV dec −1 for HER due to the abundant active sites, fast electron transport, low charge‐transfer resistance, unique architectural structure and synergistic effect of carbon sheath, nanoalloys, and oxides. Moreover, as OER catalysts, the NC/NiMo/NiMoO x hybrids require an overpotential of 284 mV at 10 mA cm −2 . More importantly, the NC/NiMo/NiMoO x array as a highly active and stable electrocatalyst approaches ≈10 mA cm −2 at a voltage of 1.57 V, opening an avenue to the rational design and fabrication of the promising electrode materials with architecture structures toward the electrochemical energy storage and conversion.