Tailoring Coordination Microenvironment of Nickel Molecular Complexes for Electrooxidation of Organic Nucleophiles.

Electrochemical oxidation of organic nucleophiles to value-added chemicals using nickel-based catalysts is promising yet hindered by the dynamic evolution of nickel coordination structures during catalysis. Herein, we engineered atomically exposed nickel molecular catalysts anchored on functional carbon black through tailored aromatic ligands coordination. This unique spatial coordination structure efficiently promotes the reconstruction of high-valence NiIII-OOH sites, which boost electrooxidation of 18 organic substrates with peak current density exceeding 800 mA cm-2. Especially, the optimal electrocatalyst achieves record mass activities of 4.38 and 4.26 A mgNi -1 for methanol and ethylene glycol oxidation, respectively. In situ characterization and theoretical analyses elucidate that the atomically exposed NiIII-OOH centers would directly adsorb organic substrates, thereby enhancing C─C/C─H bonds cleavage efficiency. Meanwhile, the proton abstraction from C─H bond would enable reversible redox cycling between NiII-OH and NiIII-OOH, sustaining catalytic activity. This study advances the understanding of organic oxidation mechanisms and showcases the great potential of molecular complexes in electrocatalysis.