Heterometallic Electrocatalysts Derived from High-Nuclearity Metal Clusters for Efficient Overall Water Splitting

The development of cost-effective electrocatalysts with an optimal surface affinity for intermediates is essential for sustainable hydrogen fuel production, but this remains insufficient. Here we synthesize Ni₂P/MoS₂-CoMo₂S₄@C heterometallic electrocatalysts based on the high-nuclearity cluster {Co₂₄(TC4A)₆(MoO₄)₈Cl₆}, in which Ni₂P nanoparticles were anchored to the surface of the MoS₂-CoMo₂S₄@C nanosheets via strong interfacial interactions. Theoretical calculations revealed that the introduction of Ni₂P phases induces significant disturbances in the surface electronic configuration of Ni₂P/MoS₂-CoMo₂S₄@C, resulting in more relaxed d–d orbital electron transfers between the metal atoms. Moreover, continuous electron transport was established by the formation of multiple heterojunction interfaces. The optimized Ni₂P/MoS₂-CoMo₂S₄@C electrocatalyst exhibited ultralow overpotentials of 198 and 73 mV for oxygen and hydrogen evolution reactions, respectively, in alkaline media, at 10 mA cm^–2. The alkali electrolyzer constructed using Ni₂P/MoS₂-CoMo₂S₄@C required a cell voltage of only 1.45 V (10 mA cm^–2) to drive overall water splitting with excellent long-term stability.