Construction of Fe–In Alloy to Enable High Activity and Durability of Fe–N–C Catalysts

The strategic regulation of the electronic properties and coordination environment of single-atom sites through the integration of metal nanoclusters emerges as a promising route to enhance the oxygen reduction reaction (ORR) performance of Fe–N–C materials. Here, a catalyst (FeIn–NC) is successfully developed in which Fe–N–C materials encapsulate Fe–In alloy nanoclusters, and it shows excellent ORR activity and durability under alkaline conditions, with a high half-wave potential of 0.924 V (vs RHE) and a zinc–air battery power density of 202.1 mW cm⁻², superior to commercial Pt/C catalysts. Theoretical calculations unravel that the synergistic interaction between the Fe–In alloy and the FeN₄ single-atom site modifies the electronic structure and charge distribution at the FeN₄ site, thereby enhancing the electrocatalytic activity and durability of the ORR. Potential-dependent microkinetic modeling (MKM) further discloses the ORR mechanisms on the identified FeN₄ sites. This work provides a viable strategy for the ORR improvement of Fe–N–C materials via p-block metal-based alloy nanoclusters.