▎ 摘　　要

Graphene-supported nanocluster arrays are interesting model systems to bridge the materials gap to real catalysts. This model system was used to investigate the poisoning of platinum particles by sulfur, which is crucial for many industrial processes. The adsorption and desorption of the probe molecule CO on sulfur-poisoned platinum nano particles on graphene were studied using high-resolution X-ray photoelectron spectroscopy. We observed a strong blocking of edge adsorption sites and a weaker blocking of on-top sites on facets; bridge sites are only blocked at higher sulfur coverages. During heating, CO diffuses to edge sites, thereby displacing the sulfur to the facets. Our results show interesting similarities to stepped platinum single crystals.