Si-doped mesoporous TiO2 continuous fibers: Preparation by centrifugal spinning and photocatalytic properties

TiO2 continuous fibers were prepared by a sol-gel method combined with centrifugal spinning without any template or binder polymer. The fibers were characterized using XRD, FT-IR, SEM, N-2 adsorption-desorption, and UV-vis DRS. The addition of silica was a crucial factor for obtaining long fibers because of the formation of Ti-O-Si networks. The effects of dopant contents and heat treatment temperatures were studied. It was found that the proper addition of silica into titania could improve the surface texture and enhance the thermal stability and crystal stability. When Si/Ti molar ratio was 0.15, mesoporous TiO2 fibers with a BET surface area up to 127.7 m(2) g(-1) were obtained after heat treatment at 700 degrees C. It displayed the highest photoactivity of all, and the degradation rate of X-3B in aqueous solution reached 99.6% after 75 min under UV irradiation. Furthermore, the degradation rate and the mineralization rate of X-3B were 94.7% and 58.9% after 3 h under solar irradiation, respectively. In addition, it was worthwhile to mention that the degradation efficiency was also more than 90% after 6 cycles. (C) 2009 Elsevier B.V. All rights reserved.