Ultrasound treatment improved the photocatalytic performance of CdS-embedded 3D TiO2. An optimum CdS loading was observed for the synthesis of the composites. Operating conditions for photocatalysis of limonene and toluene were investigated. 2-Propanol can be used to explore the mechanistic role of OH in gas decomposition. CO and organic byproducts were formed during the photocatalysis of target compounds.