The imaging of active nanoparticles represents a milestone in decoding heterogeneous catalysts dynamics. We report the facet resolved, surface strain state of a single PtRh alloy nanoparticle on SrTiO3 determined by coherent x-ray diffraction imaging under catalytic reaction conditions. Density functional theory calculations allow us to correlate the facet surface strain state to its reaction environment dependent chemical composition. We find that the initially Pt terminated nanoparticle surface gets Rh enriched under CO oxidation reaction conditions. The local composition is facet orientation dependent and the Rh enrichment is non-reversible under subsequent CO reduction. Tracking facet resolved strain and composition under operando conditions is crucial for a rational design of more efficient heterogeneous catalysts with tailored activity, selectivity and lifetime.
@article{arxiv.2103.01573,
title = {Single Alloy Nanoparticle X-Ray Imaging during a Catalytic Reaction},
author = {Young Yong Kim and Thomas F. Keller and Tiago J. Goncalves and Manuel Abuin and Henning Runge and Luca Gelisio and Jerome Carnis and Vedran Vonk and Philipp N. Plessow and Ivan A. Vartanyants and Andreas Stierle},
journal= {arXiv preprint arXiv:2103.01573},
year = {2022}
}