Heterometallic doping regulation in two-dimensional metal–organic frameworks for enhanced electrocatalytic oxygen reduction reaction: a computational study

Abstract

Two-dimensional metal–organic frameworks (2D MOFs) show exceptional promise for the oxygen reduction reaction (ORR) due to their high-density exposed metal sites and tunable structures. However, enhancing electrocatalytic activity and elucidating underlying mechanisms remain key challenges in catalyst design. This study employs heterometallic doping in Co-HHB (HHB = 1,2,3,4,5,6-hexahydroxybenzene) to construct bimetallic MOFs TM_xCo_3-x (TM = Fe, Ni, Cu; x  = 1, 2). Based on density functional theory (DFT) calculations encompassing geometric optimization, adsorption energy, and reaction free energy, we establish that the Cu₁Co₂ configuration delivers superior ORR activity, achieving an ultralow theoretical overpotential of 0.20 V. Electronic structure analysis reveals that Cu doping modulates the valence electron configuration of Co sites, optimizing intermediate adsorption strength. This synergistic effect facilitates the ORR pathway by balancing adsorption/desorption energetics. Therefore, bimetallic regulation in two-dimensional MOFs is an effective modification strategy for enhancing electrocatalytic ORR activity, and the intrinsic electronic structure regulation mechanism provides valuable theoretical insights for the design of high-performance electrocatalysts.