Self-encapsulating FeCo nanoparticles into dual-single-atom-anchored CNTs as a robust dynamic catalyst for oxygen conversion in zinc–air batteries

Abstract

Dual-single-atom catalysts often struggle to balance high metal loading with structural stability in zinc–air batteries. To address this issue, this study designed a hierarchical catalyst by co-confining CoFe dual-single atoms and FeCo nanoparticles within hollow carbon nanotubes via a ZnO-templated method, constructing a dynamic catalytic system centered on “nanoparticle-induced single-atom sites.” In this structure, the carbon nanotube walls provide spatial confinement, while the strong electronic interaction at the FeCo nanoparticle/carbon nanotube interface dynamically stabilizes the electronic structure of adjacent single-atom sites, forming highly active and self-adaptive catalytic centers. The one-dimensional channels further ensure efficient mass transport. This catalyst exhibits outstanding bifunctional oxygen electrocatalytic activity, with an ORR half-wave potential of 0.944 V and an OER overpotential of 0.271 V at 10 mA cm⁻². In zinc–air batteries, it achieves stable operation for 360 hours with a low charge–discharge voltage gap of only 0.865 V at 10 mA cm⁻². The exceptional performance originates from the dynamic single-atom centers induced by the nanoparticles, which synergistically suppress atomic migration/dissolution. This work provides a new strategy for designing high-performance and stable dual-single-atom catalysts through multi-scale structural control of dynamic active sites.