科研之友
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摘要
The ultrafine dispersing and subsequent self-assembling process of montmorillonite (MMt) micro layers were controlled by pH switch to build sandwich-layer structure of TiO2 intercalated MMt. Different pH controlling processes were carried out during hydrothermal synthesis, and the as-prepared samples were characterized by XRD, SEM, TEM, XPS, FTIR, UV-vis spectra, nitrogen adsorption/desorption analysis, and photocatalytic activities. The FTIR and XRD results reveal that TiO2 is chemically combined with MMt layers by hydrothermal process, which hinders the grain growth and anatase-to-rutile phase transition of loaded TiO2 and the transition temperature is approximately 900 degrees C. The micro-morphology analysis shows that TiO2 nanoparticles could be successfully intercalated into MMt layers by special pH controlling process, resulting in the expansion of interplanar spacing of MMt and increased interface action between TiO2 nanocrystals and MMt sheets. The size of TiO2 intercalated in the MMt is approximately 15 nm, which is much smaller than blank TiO2. Furthermore, comparing with ordinary surface loaded TiO2, the TiO2 nanoparticles sandwiched in MMt layers display much higher UV-light photocatalytic degradation activity and reliable recycling stability to methyl orange (MO), due to more Ti3+ active sites and larger porous volume caused by intercalation. Differed from previous TiO2-MMt, which has directional arrangement and narrowed interlayer spacing of (001) faces of MMt, such novel pH controlling process gives full play to the advantage of clay sheets to build layered limited TiO2, and solves traditional drawbacks of MMt supporting materials such as light barrier and limited mass transfer efficiency in composed photocatalysts.
- 出版日期2018-5-1
- 单位吉林大学
