Subnano cluster catalysts, while highly promising due to unique activity, selectivity, and atom-efficiency, are limited in wider applications, as they are prone to deactivation via sintering. Even size-selection, which was previously shown to reduce sintering of nanoparticles, cannot reduce the sintering of highly fluxional subnano clusters, due to their inherent isomeric diversity. Here, we use a combination of theory and experiment to show that Pt clusters on Al2O3 exhibit size-dependent sintering resistance. We furthermore show that Pt4/Al2O3 and Pt7/Al2O3 are “magic” sinter-resistant cluster sizes. Their stability is attributed to the greater degree of bulk-like crystallinity of the dominant isomers. In addition, we identify different spatial signatures characteristic of the sintering of clusters with differing sintering stabilities.
Supplementary Information: “Magic” sinter-resistant cluster sizes of Ptn supported on Alumina
Details of Monte Carlo simulations and analysis. Extend of sintering with and without isomeric diversity. Breakdown of competing pathways per cluster size. Full final cluster size distributions post-simulation. Bonding analysis.