Theory-guided design of atomic Fe–Ni dual sites in N,P-co-doped C for boosting oxygen evolution reaction

Abstract

The principle of how the active sites of catalysts match the reaction intermediates has long been sought after. Herein, we report a theory-guided atomic design and fabrication strategy of a C-based catalyst with diatomic Fe–Ni and N,P co-doping for the oxygen evolution reaction (OER). The configuration matching (with O∗ on the Ni site and OH∗ on the adjacent Fe site) and the local electron engineering by P doping significantly facilitate the rate-determining step of OOH∗ formation. Such diatomic Fe–Ni is demonstrated to be thermodynamically stable and is precisely constructed through the pyrolysis of Fe 3+ /Ni 2+ -adsorbed ZIF-8 under NaH 2 PO 2 co-feeding. The synergistic effects endow the catalyst with a low overpotential and high turnover frequency, exceeding all transition-metal N-based catalysts so far as we know, which provides a deep understanding of the OER mechanism on heteroatomic metal-based catalysts. This strategy will pave the way for novel catalyst design and the replacement of noble-metal-based catalysts. • Atomic Fe–Ni dual sites in N,P-co-doped C as efficient OER catalyst • The OER mechanism on Fe–Ni dual sites with P doping is explored by DFT calculation • The rational fabrication of Fe–Ni dual sites is confirmed by GC-MC simulation • A high-performance Zn-air battery with an Fe-Ni-N-P-C-based cathode is achieved The global warming caused by fossil fuels stimulates the development of clean-energy devices, such as metal-air batteries, water splitting, and fuel cells, in which the anodic reaction of the oxygen evolution reaction (OER) has attracted great attention. However, the intrinsic sluggish kinetics and costly noble-metal-based catalysts have vitally limited its flourishing. Great efforts have been devoted to developing cost-effective transition-metal-based catalysts, but the understanding of synergistic effects of multi-active sites and the controllable fabrication strategies are still in their infancy. We report a theory-guided atomic design and fabrication of diatomic Fe–Ni sites in N,P-co-doped C, which achieves geometric and local electron matching with OOH∗ intermediate, leading to superior OER performance. Our work provides deep insight into how active sites interact with intermediates at an atomic level and will pave the way for the development of electrocatalysts with multi-active sites. Pan et al. provide a theory-guided design and fabrication strategy of atomic Fe–Ni dual sites in N,P-co-doped C as catalysts for the oxygen evolution reaction (OER). The enhanced OER activity originates from the geometric and electron matching between Fe–Ni dual sites with P doping and OOH∗ intermediates. This strategy, considering configuration matching with local electron modulation, will pave the way for the rational design, fabrication, and mechanistic understanding of catalysts with dual-metallic active sites in various complex reaction systems.