Investigating the Metastability-Triggered Reactivity of Pt7,8 Clusters on Graphene: Unraveling Statistical Ensemble Representation for ORR in Gas and Implicit Solvent Phases

Abstract

Subnanoclusters have emerged as an exciting platform in heterogeneous catalysis due to their high metal utilization and superior performance. However, understanding the dynamic reconstruction of the active sites of these isomers under experimental conditions is crucial. Herein, we represent a multiscale investigation to decode the solvent-dependent fluxionality of Pt7 and Pt8 clusters on graphene support in the gas and solvent phases via an implicit solvation model. We show that under electrochemical reactions, high fluxionality associated with the metastable clusters demands a statistical ensemble-based representation to understand their activity trend, in addition to stable global minima (GM). During oxygen reduction reaction (ORR) mechanistic investigation, distinct adsorption behavior, development of the scaling relationship, and reduced overpotential values represent an enhanced ORR activity at the subnano regime, compared to bulk and nanoclusters. Additionally, we observe that the significant charge transfers, the interactions between clusters and support, and the presence of an aqueous environment facilitate the increased contribution from metastable isomers within the low-energy metastable ensembles (LEMEs) toward overall ORR activity. At last, through ab initio thermodynamic analysis, we represent the stable oxidized phase and activity of the Pt clusters under the ORR conditions. Our approach emphasizes the significance of investigating support and solvent-dependent metastability-triggered reactivity to address the complexities of electrified interfaces in catalytic simulations. � 2024 American Chemical Society.