Shuhuan Han, Xiaojie Wang, Jun Bao, Qinghe Yang, Xiaofei Zeng, Dapeng Cao
Abstract Developing efficient electrolytic water catalysts with long‐term stability at high current densities is still a challenge for their large‐scale application. Herein, a hydrogen evolution reaction (HER) electrocatalyst with Mo single atom interfaced with Ru atomic clusters loaded on N‐doped hollow carbon spheres (Ru‐MoN 4 ‐NC) is constructed. The strong metal‐support interaction (MSI) between Ru clusters and NC carrier is achieved through the formation of Ru‐Mo and Mo─N bonds, which inhibit the shedding and agglomeration of Ru atoms, contributing to the obvious improvement of the electrocatalytic stability. Furthermore, the oxyphilic MoN 4 sites facilitate the adsorption of hydroxyl species, promoting the dissociation of water and thereby boosting the HER activity. Ru‐MoN 4 ‐NC as a cathode catalyst in anion‐exchange membrane water electrolyzer (AEMWE) has excellent stability (1200 h) at the industrial‐grade current density of 1 A cm −2 with a low cell voltage (1.72 V). Simultaneously, it exhibits excellent alkaline HER activity with a low overpotential (8 mV @10 mA cm −2 , 138 mV @1 A cm −2 ) and high mass activity (7.5 A mg @50 mV).