Tailoring atomic strain environment for high-performance acidic oxygen reduction by Fe-Ru dual atoms communicative effect

Elucidating how the local strain environment of single atoms affects their impact on a sluggish acidic oxygen reduction reaction (ORR) is important for the design and construction of highly active electrocatalysts. Here, we report that the atomic strain geometry of Fe single sites is exclusively regulated by the communicative effects of dual atoms. Theoretical analysis reveals that Fe-Ru dual atoms in a moderate strain environment achieve the lowest Gibbs free energy barrier during an ORR. Impressively, FeRu-N-C with an FeRuN₈ moiety exhibits the highest acidic ORR performance, with a half-wave potential (E_1/2) of 0.860 V and only a 17-mV loss in E_1/2 after 50,000 potential cycles. Operando characterization and electronic configuration analysis demonstrate that moderately strained Fe sites promote hydrogenation desorption of (oxy-)hydroxyl by enabling more electrons to occupy antibonding orbitals. This study describes a promising way of investigating high-performance single-atom-based catalysts by tailoring the atomic strain environment.