Ni‐Assisted Low Temperature Synthesis of MoCx with Enhanced HER Activity

Abstract Here we report a novel one‐pot approach to synthesize MoC x catalysts at much lowered temperature for hydrogen evolution reaction (HER) in acidic solution. A room‐temperature co‐precipitation reaction among Ni 2+ , MoO 4 2− and 2‐methylimidazole in an aqueous solution produced a Mo−Ni−imidazole complex, which was used as the precursor to fabricate MoC x . The morphological and chemical properties of the obtained MoC x affected by calcination and other additive metal sources (like Fe, Co, Cu) were investigated in detail. We demonstrated that Ni−Mo alloying took place prior to MoC x formation during heating, which catalyzed the crystallization of MoC x at relatively low temperature. The MoC x /Ni‐650 catalyst exhibited a quite low overpotential of 172 mV at 20 mA cm −2 . The high performance originates from the synergistic effect between MoC x and Ni−Mo alloy, high ratio of Mo 3+ /Mo 2+ , as well as high electrochemically active surface area and low charge‐transfer resistance. This work would open a new way to the design and fabrication of other transition‐metal carbide catalysts.