Photo-oxidation of gas-phase cyclohexane species over nanostructured TiO2 fabricated by different strategies

TiO2 photocatalyst Degussa P25 was modified by three methods: SO42− acidification (labeled as STH), SO42− acidification combined with microwave irradiation (labeled as STW), and microwave irradiation (labeled as WT), respectively. FT-IR and XRD were used to characterize the structural properties of these TiO2 samples, whereas surface photovoltage spectroscopy (SPS) provided important information on the photoelectric properties. The photo-oxidation of gaseous cyclohexane over P25, STH, STW and WT was monitored by in-situ infrared technology. The experimental results demonstrated that the modified TiO2 samples were more active than the original P25 and followed this order: WT > STW > STH > P25. During the photocatalytic oxidation of cyclohexane over WT, cyclohexane was mineralized into carbon dioxide and water. Moreover, CO was also produced in small amount.