Recent Developments in Gold Nanomaterial Catalysts for Oxidation Reaction through Green and Sustainable Routes - Advanced Materials for Agriculture, Food and Environmental Safety - page 210

Figure 8.13 Aberration-corrected HAADF-STEM images of Au atoms and gold clusters
in (A and B) the inactive and (C and D) the active Au/FeO x catalysts; the images were
acquired by aberration-corrected STEM. Reproduced with permission from [79].
benei cial for the catalyst reactivation. It can be concluded that it is highly
benei cial to perform the direct propene epoxidation in a microreactor sys-
tem at the highest possible feed concentrations for each of the reactants,
as this results in the highest propene oxide productivity and the lowest
deactivation rate.
8.3 ReactionMechanism
Several studies have been done to elucidate the reaction mechanism of
direct propylene epoxidation over titanosilicate supported gold nanopar-
ticle catalyst (Figure 8.14). Formation of hydroperoxo species seems to be
indispensable for producing PO by direct epoxidation of propylene in the
presence of H 2 and O 2 over gold surface, as revealed by the results of Haruta
et al. [80]. For many years the formation, characterization and reactivity of