Tunable Multimetallic Single-Atom Catalysts for Efficient Hydrogen Evolution Reaction

Designing single-atom catalysts (SACs) with various metal atoms can significantly expand their range of applications. In this study, a scalable strategy is developed to synthesize a series of transition metal (TM = Mn, Fe, Co, Ni, and Cu) SACs with widely tunable compositions, progressing from unitary to binary (CoNi), ternary (MnCoNi), quaternary (MnFeCoNi), and quinary (MnFeCoNiCu) atoms. High loadings of TM atoms (>10 wt%) are successfully embedded in porous N-doped carbon nanoparticle supports derived from pyrolyzed zeolitic imidazole frameworks (ZIF-8). All SACs feature a TM–N4 coordination structure. Among them, the MnCoNi ternary composition exhibited the greatest synergistic effect, enhancing electrocatalytic activity toward the alkaline hydrogen evolution reaction (HER). Ex situ X-ray absorption fine structure data indicate that the multicomponent SACs facilitates more efficient electrolyte adsorption, thereby accelerating the HER kinetics.