Herein, we report for the first time
the visible-light-assisted
rate enhancement for glycerol oxidation using direct plasmonic photocatalysis.
Au nanoparticles were loaded on various mesoporous SiO<sub>2</sub> supports, and the catalytic performance was investigated with and
without visible-light illumination. Monodispersed mesoporous silica
spheres loaded with Au nanoparticles demonstrated a superior photoassisted
catalytic rate enhancement compared to Au loaded ordered mesoporous
silica (SBA-15, KIT-6, and MCM-41). The enhancement is attributed
to the particle size of the Au nanoparticles and better light interaction
resulting from the small SiO<sub>2</sub> domains. Au loaded monodispersed
mesoporous silica spheres exhibit a constant and remarkably small
particle diameter of 2 nm at Au loadings of up to 15 wt % as a result
of the support’s small domain size and efficient pore confinement.
The performance of the Au catalyst could be further improved by preparing
bimetallic AuCu nanoparticles. Synergistic effects between Au and
Cu improved the glycerol conversion by a factor of 2.5 and the dihydroxyacetone
selectivity from 80% to 90% compared to monometallic Au catalysts
