| Summary: | 碩士 === 國立成功大學 === 資源工程學系碩博士班 === 98 === Abstract
TiO2 has the characteristics of large band gap and non-toxic, and therefore is extensively used as a photocatalyst material. Recent researches show that how to overcome the deficiencies to increase the activity of TiO2 due to its low surface area.
In this study, halloysite is used as substrate for loading TiO2 particles, which was prepared by sol-gel method. Aging treatment may modify the agglomeration and decrease crystallite size of TiO2.The transformation temperature of anatase-to-rutile phase was postponed because of heterogeneous nucleation mechanism and aging treatment. In commercial applications, more low-cost halloysite could partially replace the composite of TiO2 to reduce costs efficiency in raw materials.
The composite powders were characterized by XRD, BET, SEM and so on for assuming that halloysite is regarded as substrate and TiO2 is dispersed on it. The surface area increased from 24.65 m2/g to 32.217 m2/g at 750℃ after aging. The transformation temperature of anatase-to-rutile phase increased from 650℃ to 850℃. The result of FTIR confirmed the chemical bonding of Si-O-Ti, and found that aged composite powders with high specific surface area and thermal stability. The results of MB degradation showed the photoactivity of the aged composite was higher than which without aged composite.
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