Thermal and photochemical degradation of dimethylsulfoxide on TiO2

Dimethylsulfoxide (DMSO) on TiO2 is subjected to thermal decomposition, producing the surface species of CH3O, HCOO and S under vacuum. The formation of CH3O and HCOO is likely originated from the transient reaction intermediate of –OCH2O–, which is formed by dissociating both the C–S and C–H bonds of DMSO. O2 has negligible effect on the thermal decomposition rate of DMSO, but oxidizes the reaction product of S to SO4. Photodegradation of DMSO on TiO2 generates CH3O, HCOO and CH3S in the absence of O2. However, the CH3S is further oxidized into CH3SO3 on the surface with O2.