Effect of surface ethoxy groups on photoactivity of TiO2 nanocrystals

TiO2 nanocrystals modified by ethoxy groups were prepared by a facile nonhydrolytic solvothermal method and characterized by XRD, TEM, TG-DTA and XPS, which showed an enhanced visible-light photocatalytic activity on the degradation of Rhodamine B compared with TiO2 modified by benzyloxy groups and the “naked” TiO2. The adsorption and degradation pathway of Rhodamine B on TiO2 modified by ethoxy groups were also investigated. The zeta-potential (ζ) results showed that the TiO2 modified by ethoxy groups had high negative surface charge, which incited the positive –N(Et)2 group of RhB absorbing on the TiO2 surface and preferably led the N-dealkylation pathway under visible light irradiation.