Curved Interfaces Enhanced Oxygen Reduction Reaction by PtCo Alloys Anchored MOF-Derived Carbon

Abstract

The carbon supports employed in oxygen reduction reaction (ORR) catalysts frequently exhibit crumpled, curled, or other curved morphologies-features. The local microenvironment generated by such curved interfaces and its impact on the electronic structure of active sites as well as reaction kinetics, remain to be studied. Herein, the finite element method was employed to elucidate the evolution of the local catalytic microenvironment during the pyrolysis of ZIF-67 from the perspective of geometric distortion, the results revealed that moderate interfacial curvature can significantly enhance the local electric field strength and promote O 2 enrichment. Guided by the simulation results, MOF-derived carbon with an optimal curved configuration was constructed via control of the pyrolysis temperature. After etching, metal ion adsorption, and H 2 reduction, MOFderived carbon materials loaded with PtCo alloy were obtained (PtCo/NCs). As expected, the PtCo/NCs-900 sample with a moderately curved interface exhibited outstanding ORR performance, with a half-wave potential of 0.831 V, and 91.7% activity retention after 50000 s. Density functional theory calculations demonstrated that the curved interface in PtCo/NCs-900 induces electron redistribution, shifts the d-band center of Pt and optimizes *OH desorption behavior, thereby lowering the O 2 diffusion barrier, facilitating electron transfer, and ensuring sufficient O 2 supply.As an air-cathode catalyst, PtCo/NCs-900 sample delivered a peak power density of 159 mW cm -2 and a specific capacity of 837 mAh g -1 Zn , demonstrating its potential for practical energy applications.