Effects of surface modification with DBS groups on gas phase photocatalytic performance of nanosized TiO2

Sodium dodecylbenzenesulfonate groups(DBS)-modified TiO2 nanoparticles were directly prepared by a sol hydrothermal method, the effects of DBS modification on photocatalytic performance, including mainly activity and lifetime, of nanosized TiO2 in the degradation of gaseous n-C-5,H-12 were studied, together with the affecting mechanism of DBS modification by means of surface photovoltage spectroscopy( SPS) and photoluminescence(PL). The results show that the modification with DBS molecule groups can inhibit the crystallite growth, improve particle dispersibility, enhance the capability to adsorb organic substance, and increase separation rate of photoinduced charges, which are responsible for the increase in the photocatalytic activity. Interestingly, the lifetime of the surface-modified photocatalyst does not decrease, compared with that of unmodified sample, demonstrating that DBS groups are relatively stable. In addition, the photocatalytic reaction of gaseous n-C5H12 on TiO2 follows a Langmuir-Hinshelwood model, and also is a pseudo-first order reaction.