Curvature-dominated microenvironment modulation enables efficient electrocatalytic oxygen reduction

The oxygen reduction reaction (ORR) critical for electrochemical energy conversion systems suffers from sluggish kinetics and high overpotentials that hinder the efficiency of these technologies. Herein, a curvature-dominated microenvironment modulation strategy is demonstrated to enhance ORR performance via engineering a helical hollow carbon nanotube with embedded sub-nanometer tungsten nitride (W₂N) clusters. This architecture yields optimized electrostatic field distributions and reduced d-band center of W₂N, thereby promoting the enrichment of OH⁻, the adsorption of oxygen, and the desorption of oxygen intermediates ( $\ast$OH). The catalyst shows remarkable ORR activity with a high onset potential of 1.00 V and a half-wave potential of 0.89 V, outperforming both Pt/C and other W₂N-based catalysts. Theoretical calculations verify that the curved support enhances the electron delocalization within the W₂N clusters, regulating the interaction between the catalyst and reactants. Our findings establish a general design principle of curvature-induced microenvironment modulation and offer a new pathway toward designing efficient electrocatalysts for sustainable energy storage applications.