Engineering Spatial Interface in Supported Molecular Complexes for Ampere-Level Electrocatalytic Oxygen Evolution

Homogenized molecular complexes with active single sites hold great promise for electrocatalytic conversion processes. However, the influence of the spatial gap between coordination complexes and the carbon support on electron shuttling remains poorly understood. Herein, we demonstrate a supramolecular architectural strategy that leverages oxygen sites to strengthen the complex-support interactions, thereby elucidating the oxygen evolution reaction (OER) catalytic mechanism effected by the spatial gap. Experimental results reveal that the narrow gap would benefit electron shuttling and stabilize the molecular complexes, enabling the ampere-level current densities. Typically, the optimized biphenyl-4,4'-dicarboxylic acid-coordinated Fe-Ni complexes exhibit superior electrocatalytic performance with a current density of 1.5 A cm^-2 and a mass activity of 41,206 A g_Fe/Ni^-1 at an overpotential of 0.33 V. Theoretical studies further demonstrate that the highly electrophilic oxygen bridging between iron and nickel sites would promote the formation of key intermediates on iron sites (Fe-OOH*). These findings demonstrate the significant roles of complex-support interactions in designing heterogeneous molecular complexes.