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. Incorporating p-block metal indium into the Fe-N-C system to form Fe-In alloy can strongly modify the electronic structure and charge distribution of FeN4 sites. The synergistic effect between FeN4 site and Fe-In alloy significantly enhances catalytic activity and durability, by boosting OH* desorption for an improved ORR kinetics. image