Curvature-dominated microenvironment modulation enables efficient electrocatalytic oxygen reduction

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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-nano W₂N clusters. This architecture yields optimized electrostatic field distributions and reduced d-band center of W₂N, thereby promoting enrichment of OH-, adsorption of oxygen and desorption of oxygen intermediates (*OH). The catalyst shows remarkable ORR activity with high onset potential of 1.00 V and half-wave potential of 0.89 V, outperforming both Pt/C and other W₂N-based catalysts. Theoretical calculations verify that the curved support enhances 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.