Size Effect of Au Particles

Reaction Pathways for Propene Epoxidation over Au/Ti02 

Nijhuis et al. proposed a different reaction route, in which the role of the periphery around Au NPs is not expUcitly described [35, 36]. Based on a detailed FT-IR spectroscopic investigation, they indicate that C3H6 reacts with the Ti02 surfaces to form a bidentate propoxy species with the help of Au NPs. Over the Au surfaces, the peroxide species are formed by the reaction of O2 with H2, which is the ratedetermining step. The bidentate propoxy species desorb with the assistance of the peroxide species to produce PO and water. This hypothesis is based on the theoretical prediction that gold is active to produce H2O2 from H2 and O2 [37] and on some recent experimental results for direct H2O2 synthesis [38, 39]. 

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