Photocatalytic selective oxidation of the terminal methyl group of dodecane with molecular oxygen over atomically dispersed Ti in a mesoporous SiO2 matrix

Abstract

Extraordinarily high selectivity (80-93%) for the oxyfunctionalization of the terminal methyl group was discovered in the photocatalytic selective oxidation of dodecane with molecular oxygen in a continuous flow system under mild gas phase reaction conditions over mesoporous TiO2-SiO 2 mixed oxide photocatalysts. The oxygenated hydrocarbon products were mainly aldehydes with carboxylic acids and ketones as minor products. By dispersing most of the Ti atomically in a tetrahedral coordination in a SiO 2 matrix, the oxygenated products were stabilized by diluting contiguous Ti sites present on the surface of TiO2 particles. The preferential oxidation of the terminal methyl group was ascribed to the extensive C-C bond breaking by photogenerated holes prior to oxyfunctionalization.