Understanding the Position Effects of Monoatom Doping in Silver Nanoclusters on Oxygen Reduction by Single Entity...

Alloying nanoclusters (NCs) with monoatom doping represents an effective strategy to enhance catalytic performances due to the synergistic interactions between the dopant and host atoms. However, in-depth understanding the position effects of monoatom doping within alloying NCs, particularly at the atomic level, remains elusive. Here, we employed single entity collision electrochemistry method to investigate the electrocatalytic behaviors of individual monoatom-doped bimetallic M₁Ag₂₄ (M = Ag, Au, Pt, and Cu) NCs toward oxygen reduction reaction (ORR). By relying on high-resolution and high-throughput electrochemical measurements, we successfully discriminated the effects of monoatom variation in M₁Ag₂₄ NCs on ORR activity at the single atom resolution and identified different M₁Ag₂₄ NCs across characteristic populations. Our experimental findings and theoretical calculations reveal the electrocatalytic reaction dynamics associated with intracluster migration of Au monoatom during the dynamic alloying process of Au₁Ag₂₄ NCs. This work demonstrates a novel approach for in situ identifying the position effects of foreign doping atoms on the electrocatalytic activity of alloy NCs at the single atom level.