Comparative photocatalytic behavior of photocatalysts (TiO 2 , SiC, Bi 2 O 3 , ZnO) for transformation of glycerol to value added compounds

Four types of semiconductors were used as photocatalyst to convert glycerol to other value added compounds at identical testing condition in the presence of H 2 O 2 as the electron acceptor. The results demonstrated that the band gap energy affected the photocatalytic activity of glycerol than the crystallite size and textural property of the utilized photocatalyst. The SiC, Bi 2 O 3 and ZnO achieved almost complete glycerol conversion at 8 h of reaction time, which was significantly higher than that of TiO 2 . Similar types of products, including dihydroxyacetone, glyceraldehyde, glyceric acid, glycolic acid and formic acid, were generated via all explored photocatalysts. Interestingly, one additional compound known as glyoxylic acid, an important intermediate of organic chemicals, used in medicine, spices, pesticides, paint, paper and food, was produced via Bi 2 O 3 . The reaction mechanism and the pathways of photocatalytic conversion of glycerol via Bi 2 O 3 were proposed. Finally, the reusability of Bi 2 O 3 photocatalyst was explored.