Ferrocene unit substitution in nickel(ii) porphyrin(2.1.2.1) induces an extremely low oxygen evolution reaction overpotential

Abstract

This study reports the synthesis, characterization, structure and the oxygen evolution reaction (OER) performance of ferrocene-substituted nickel(II) porphyrin(2.1.2.1) complexes. The Ni-3 complex, functionalized with two ferrocene units, demonstrates exceptional OER activity, achieving an overpotential of 280 mV at 10 mA cm⁻² in alkaline media. This enhancement is ascribed to the electron-rich ferrocene moieties, which act as efficient electron-transfer mediators during catalysis. DFT calculations corroborate these findings, revealing a theoretical overpotential of 0.79 eV for the dual-ferrocene-substituted catalyst. These results underscore the critical role of ferrocene in lowering the overpotential of molecular OER catalysts.