Synergistic Work Function Optimization via the Three-Dimensional Gradient Modulation Strategy for High-Performance ORR Electrocatalysis

The oxygen reduction reaction (ORR) is strongly governed by the adsorption of intermediates, where sluggish electron transfer limits the energy conversion efficiency. Modulating the work function (WF) of the catalyst is a promising strategy to regulate electron transfer and adsorption energetics, but most approaches rely on localized modifications, hindering balanced WF optimization. Here, we propose a three-dimensional (3D) gradient WF regulation strategy to construct a catalyst (Co3O4@Co@BN-CNTs) featuring B, N-codoped carbon nanotubes coupled with Co3O4@Co heterointerfaces. In this architecture, B and N doping modulates the carbon surface electronic structure, while nanoscale heterostructures redistribute charge at carbon–metal junctions. This 3D regulation enables precise WF tuning, optimizes intermediate adsorption, and lowers the energy barrier of the potential-determining step (PDS). As a result, the catalyst achieves excellent ORR activity with an onset potential (Eonset) of 0.99 V (vs reversible hydrogen electrode (RHE)) and a half-wave potential (E1/2) of 0.88 V (vs RHE) in 0.1 M KOH. At the same time, Co3O4@Co@BN-CNTs also shows excellent performance as a cathode material for Zn-air batteries, with a peak power density of 134.6 mA cm–2 and stable cycling over 400 cycles. This study provides new insights into multidimensional electronic structure engineering for the design of next-generation electrocatalysts.