Dual-Functional Interface Molecular Engineering of Conductive MOF Nanoarrays for Oxygen Evolution Reaction

Drawing conceptual inspiration from the inorganic-organic hybrid architecture of natural Photosystem II, this work presents a dual-functional interface molecular engineering strategy. A Ni(TCNQ)2-FcDA nanoarrays (NAs) composite catalysts were constructed by anchoring ferrocene dicarboxylic acid (FcDA), featuring both proton-relay and redox activities, onto conductive Ni(TCNQ)2 nanoarrays (Ni(TCNQ)2 NAs). Structural characterizations indicate that carboxyl groups in FcDA participate in interfacial proton transport, while Ni-Fe coupling synergistically modulates the electronic structure of the active Ni centers. Theoretical calculations indicate that this interfacial engineering induces a significant downshift in the Ni 3d orbital d-band center, effectively lowering the energy barrier for the OH to O conversion step. Consequently, the catalyst achieves a current density of 10 mA cm-2 at an overpotential of only 226 mV in 1.0 mol L-1 KOH, with a low Tafel slope of 30.4 mV dec-1 and stability exceeding 24 h. Kinetic analysis further reveals a concerted proton-coupled electron transfer (PCET) mechanism. This work presents a strategy for synergistically addressing mass transport bottlenecks and electronic structure mismatches in conductive MOFs via dual-functional molecular interface engineering.