Vapor-Phase Epoxidation of Propene over Au/Ti-MCM-41 Catalysts: Influence of Ti Content and Au Content.

Ti-MCM-41 samples were used for propene epoxidation using H2 and O2 after Au deposition by deposition--precipitation. Au nanoparticles supported on Ti-MCM-41 with Ti incorporated hydrothermally followed by post-synthesis grafting gave higher propene oxide yields than Ti-MCM-41 with Ti incorporated hydrothermally or by grafting. Au L3-edge EXAFS spectra show the presence of metallic Au for the low Au content (0.21 wt%) catalyst which is more selective to epoxidation, while at high Au loadings (0.42 wt%) oxidic Au species are observed and the catalyst shows lower epoxide selectivity. [ABSTRACT FROM AUTHOR]