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[Cao Xinyue,Tang Xiaoning,Ma Hao and Chen Yuanyuan.Study on TiO2@SiO2 photocatalytic degradation of different dyes and its mechanism[J].Rare Metal Materials and Engineering,2022,51(8):3001~3012.]
Study on TiO2@SiO2 photocatalytic degradation of different dyes and its mechanism
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Received:July 15, 2021  Revised:August 05, 2021
DOI:
Key words: photocatalytic degradation  Ti-O-Si  titanium dioxide  reactive oxide species  adsorption
Foundation item:国家重点研发计划重点专项(2017YFC0210303);昆明理工大学分析测试基金(2020M20192208030)
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Cao Xinyue,Tang Xiaoning,Ma Hao and Chen Yuanyuan  
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Abstract:
      In this paper, TiO2@SiO2 composite materials with different Ti contents were prepared. The microscopic morphology, crystal structure, chemical composition and optical properties of TiO2@SiO2 composite materials were analyzed by SEM, XRD, BET, XPS ,DRS and spectral analysis method, and photocatalytic degradation experiments were carried out. The results showed that the sample is anatase TiO2 with a spherical core-shell structure, a large specific surface area and blue shift of light response range. XPS showed that the Ti-O-Si bond is formed between TiO2 and SiO2. Ti-O-Si bond contributed to the separation of photogenerated electrons holes, and further promoted the generation of superoxide radicals in active oxygen during the photocatalytic degradation process. Due to defects and distortions produced at the interface between TiO2 and SiO2 phases, there are more oxygen vacancies were generated at the interface, thereby organic pollutants are degraded. The degradation processes of methyl orange and rhodamine B dyes were compared, it showed that the adsorption of the composite material has a significant effect on the degradation rate and degradation pathways of the dye molecules. The negative potential on the surface of the composite material strongly adsorbs the diethylamino group of the RhB molecule and dissociates the group first, and it promotes the occurrence of the characteristic blue shift effect of the solution. The synergistic effect of adsorption and active oxygen accelerates the degradation of dye molecules. The scavenger experiment also proved that the superoxide radical is the most important active substance in the degradation process of MO and RhB dye solution under visible light, and other kinds of active oxygen play an auxiliary role. The research content of this work reveals the adsorption and degradation process of different dyes, and promote the application of photocatalytic technology in sewage treatment。