Atomic-Level Integration of Heterometallic Cooperativity and Photonic Energy Harvesting in a Molecular Water...

Inspired by the heterometallic cooperativity of metalloenzymes, we report a trinuclear molecular catalyst, [NiL]₂-Ce-O-Fe, engineered through adaptive coordination of a π-extended salen-type ligand. This design integrates three synergistic functions: (1) bidirectional electron transfer (Ni → Ce via Ni-O-Ce; Fe → Ni via Fe-O-Ni) enabling reversible Ni²⁺/Ni³⁺ cycling; (2) a self-repairing Fe-O-Ce charge shuttle facilitating Ce⁴⁺/Ce³⁺ ↔ Fe⁴⁺/Fe³⁺ interconversion; and (3) broadband photoresponse (λ ≤ 750 nm) for enhanced photoelectrocatalysis. Synergy among these features lowers the energy barrier of the rate-determining step by 0.50 eV (DFT) and, under visible-light excitation, increases the Ni³⁺ content by 31% (XPS) while reducing the charge-transfer resistance by 41% (EIS). The catalyst delivers benchmark performance: an ultralow overpotential of 240 mV at 100 mA cm^-2, a Tafel slope of 48 mV dec^-1, a TOF of 0.30 s^-1, and a 90 h stability at 300 mA cm^-2. It achieves an oxygen evolution rate of 205.8 mmol h^-1 g^-1, surpassing that of state-of-the-art NiFe-LDH materials. This work demonstrates a compelling strategy for advancing molecular electrocatalysis through the atomic-level integration of multimetallic cooperativity and photonic energy capture.