Predicting Catalyst Performance From Pt/CeO₂ Redispersion Kinetics

Quantitative description of the structural dynamics of nanoparticles by kinetic data is challenging but would represent a significant knowledge leap, as this would enable the forecast of their properties, e.g., in catalysis. A striking example in catalysis is the redispersion of Pt nanoparticles into single atoms in Pt/CeO₂-based catalysts. In this work, we combined environmental transmission electron microscopy (ETEM) measurements with catalytic data to monitor the individual decay of Pt nanoparticles on defined CeO₂ nanocubes. Supported by density functional theory modeling, this provides unprecedented insight into their dynamic behavior, including kinetics. We observed that the rate of noble metal redispersion is strongly dependent on the local structural environment: the presence of other nearby nanoparticles and heterogeneities on the CeO₂ surface reduced the redispersion rate. Independent of the initial particle size and local environment, the particle volume decreases linearly in time, indicating a constant flux of Pt atoms from the nanoparticles. These findings at the atomic scale were correlated to the observed changes in the integral catalytic performance, allowing a first prediction of the catalyst activity based on the redispersion process and demonstrating how atomic-scale kinetic insights can be correlated to macroscopic effects.