Photocatalytic behavior of metal-decorated TiO2 and their catalytic activity for transformation of glycerol to value added compounds

Abstract

In this work, TiO2 was decorated with one of four different metals (Bi, Pd, Pt and Au) by sol immobilization at ambient condition. The individual addition of each metals on the TiO2 did not affect the crystallite size or band gap energy of TiO2, but increased its visible light absorption ability due to the localized surface plasmon resonance effect of the doped metals, except for Bi, as well as the mechanism of the charge transfer. Among all the prepared metal-decorated TiO2 photocatalysts, Au/TiO2 exhibited the highest visible light absorption ability and an appropriate mechanism of charge transfer, which consequently alleviated the e−–h+ recombination. It also provided the highest photocatalytic activity for glycerol conversion (92.8% at 14h) and yield of dihydroxyacetone, glyceraldehyde, glycolic acid, hydroxypyruvic acid and formaldehyde of 12.0, 23.1, 10.7, 13.6 and 15.3%, respectively.