Recent progress on ZIF-derived iron single-atom catalysts for electrocatalytic oxygen reduction

The oxygen reduction reaction (ORR) holds a pivotal role in propelling the development of advanced clean energy technologies, such as metal-air batteries and fuel cells. However, its intrinsically sluggish reaction kinetics remains a major bottleneck restricting the performance of related devices. Endowed with ultrahigh atomic utilization efficiency and unique electronic properties, single-atom catalysts (SACs) have emerged as highly promising candidates for efficient ORR electrocatalysis. By virtue of their intrinsic nitrogen-rich feature, tailorable structural configurations, and superior ability to in-situ form porous carbon derivatives, zeolitic imidazolate frameworks (ZIFs) are widely recognized as a precursor platform for SAC synthesis. Notably, ZIF-derived atomically dispersed Fe SACs have garnered extensive research interest, as Fe-N x sites typically possess optimal adsorption free energies for oxygen intermediates, which confer ORR activity and stability that can match or even surpass those of commercial Pt-based catalysts. Centering on ORR application, this review provides a comprehensive and systematic overview of the latest advances in ZIF-derived Fe SACs, accompanied by in-depth discussions of state-of-the-art synthesis strategies and their ORR catalytic performance. Finally, a forward-looking perspective on persistent challenges and prospective research directions is presented, offering actionable insights for the development of high-performance Fe SACs and facilitating their translation into practical applications.