Regulation of the electronic structure of a RuNi/MoC electrocatalyst for high-efficiency hydrogen evolution in alkaline seawater

Alkaline seawater electrolysis offers a way to generate hydrogen without carbon emissions. However, developing highly efficient catalysts that can sustain high performance and stability for the hydrogen evolution reaction (HER) in alkaline seawater is a formidable challenge. Here, a nanowire (NW) of a RuNi/MoC heterojunction embedded in N-doped carbon (RuNi/MoC@NC) was developed as a potent HER catalyst. The catalyst required only 21 mV at 10 mA cm-2 for HER in alkaline seawater, which surpasses 20% Pt/C. Moreover, using nickel foam (NF) as a catalyst carrier, an electrolyzer composed of RuNi/MoC@NC and nickel-iron layered double hydroxide (NiFe LDH) needed only 1.81 V at 500 mA cm-2 for full water splitting and showed long-term stability (over 500 h). Theoretical calculation revealed that the Ru and Ni sites in the catalyst had the optimal adsorption energy for hydrogen and water, respectively, which synergistically lowered the energy barrier for HER. This work offered an efficient method to design a highly effective HER catalyst for alkaline seawater splitting.