Zhentao Wei

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

TiO(2) 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 TiO(2) 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 3h under solar irradiation, respectively. In addition, it was worthwhile to mention that the degradation efficiency was also more than 90% after 6 cycles.

Preparation of TiO2 Continuous Fibers with Oxygen Vacancies and Photocatalytic Activity

TiO2 continuous fibers were prepared by a modified sol-gel method combined with centrifugal spinning and different heat treatment processes. The prepared fibers were characterized by TG-DSC, XRD, SEM, N2 adsorption-desorption and XPS. The photocatalytic degradation of X-3B aqueous solution was used as a probe reaction to evaluate their photocatalytic activities. The results indicated that heat treatment in steam was conductive to the rapid nucleation of anatase nanocrystal and could effectively suppress the anatase-rutile transformation. Compared with samples calcined in air, products heat treated in steam were long fibers with oxygen vacancies and abundant mesoporous structures, which enhanced their photocatalytic activities. The fibers with a high specific surface area of 87.6 m2·g−1 and the largest pore volume of 0.24 cm3·g−1 were obtained when heat treated at 400°C in steam. The sample exhibited the best photocatalytic activity and the removal rate of X-3B was 99.5% after 90 min under visible light irradiation.