Curvature strain and boron doping synergistically regulate iron single-atom catalyst for Zn-air batteries

The curvature strain and boron doping synergistically regulated Fe single-atom catalyst was fabricated. • Fe-NB-MCS delivers superior ORR performance with a large half-wave potential of 0.90 V. • Geometric strain and B doping synergistically downshift the Fe d-band center, enhancing oxygen intermediate desorption. • Fe-NB-MCS-based aqueous Zn-air battery achieves 1.51 V OCV and operates stably over 1200 h at 5 mA cm-2. • Quasi-solid-state Zn-air battery with Fe-NB-MCS maintains stable operation for over 120 h with high voltage efficiency. Using an ion adsorption-pyrolysis strategy, an iron single-atom catalyst synergistically regulated by curvature strain and B doping was successfully synthesized. Within the ordered mesopores architecture, Fe N 4 active sites are spatially confined, and the curved geometry and B doping, together with the hierarchical pore structure, establishes a distinctive catalytic microenvironment. Density functional theory calculations reveal that curvature strain and B doping downshift the d-band center and weaken the binding strength of oxygen intermediates. Notably, this synergistic effect can reduce the energy barrier of the rate-determining OH* desorption, thereby accelerating oxygen reduction reaction (ORR) kinetics. As a result, Fe-NB-MCS achieves an outstanding ORR half-wave potential of 0.90 V in alkaline media and enables exceptional durability in Zn-air batteries (ZABs), with over 1200 h of stable operation at 5 mA cm −2 , including in flexible quasi-solid-state configurations under mechanical deformation. This work establishes a robust electronic structure engineering strategy that synergizes heteroatom doping and geometric strain, for single-atom catalysts optimization, offering a generalizable design paradigm to overcome the intrinsic kinetic bottlenecks of ORR. Download: Download high-res image (413KB) Download: Download full-size image