The dynamic structure of Au38(SR)24 nanoclusters supported on CeO2 upon pretreatment and CO oxidation
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Atomically precise thiolate protected Au nanoclusters Au38(SC2H4Ph)24 on CeO2 were used for in-situ (operando) extended X-ray absorption fine structure/diffuse reflectance infrared fourier transform spectroscopy and ex situ scanning transmission electron microscopy–high-angle annular dark-field imaging/X-ray photoelectron spectroscopy studies monitoring cluster structure changes induced by activation (ligand removal) and CO oxidation. Oxidative pretreatment at 150 °C “collapsed” the clusters’ ligand shell, oxidizing the hydrocarbon backbone, but the S remaining on Au acted as poison. Oxidation at 250 °C produced bare Au surfaces by removing S which migrated to the support (forming Au+-S), leading to highest activity. During reaction, structural changes occurred via CO-induced Au and O-induced S migration to the support. The results reveal the dynamics of nanocluster catalysts and the underlying cluster chemistry.
CitationPollitt, S. [et al.]. The dynamic structure of Au38(SR)24 nanoclusters supported on CeO2 upon pretreatment and CO oxidation. "ACS catalysis", 8 Maig 2020, vol. 10, núm. 11, p. 6144-6148.