SiO2@Ag@SiO2@TiO2核壳结构的制备及其光催化降解性能

光催化是一种绿色且高效的降解染料污染物的方式, 在水污染治理中应用广泛。本研究以SiO₂为核层, 依次采用氧化还原法、改进的Stöber法及水热法合成SiO₂@Ag@SiO₂@TiO₂多层核壳结构作为光催化剂用于染料污染物降解, 并探讨了硝酸银(AgNO₃)、正硅酸乙酯(TEOS)、钛酸四丁酯(TBOT)等用量对包覆效果的影响。采用不同表征手段对样品的微观形貌、物相结构、孔结构参数和光电性能进行分析表征。结果表明, 当AgNO₃、TEOS、TBOT与SiO₂的质量比为5 : 2.4 : 6 : 1, 多层核壳结构每层均达到最优包覆效果。与SiO₂@TiO₂和SiO₂@Ag@TiO₂催化剂相比较, SiO₂@Ag@SiO₂@TiO₂核壳结构的光催化剂具有更佳的光催化活性, 光照45 min可降解93%的MB溶液, 经4次循环后其光催化效率为90%。

Preparation of SiO2@Ag@SiO2@TiO2 Core-shell Structure and Its Photocatalytic Degradation Property

Photocatalytic degradation is an eco-friendly and high-efficiency way to degrade dye pollutants which has broad application prospects in water pollution control. In this study, the multi-layer core-shell structure of SiO₂@Ag@SiO₂@TiO₂ was synthesized by different methods as a photocatalyst for pollutant degradation, with oxidation-reduction method, modified Stöber method and hydrothermal method in turn. Effect of silver nitrate (AgNO₃), tetraethyl orthosilicate (TEOS) and tetrabutyl titanate (TBOT) on the coating effect were discussed. Microstructure, phase structure, pore structure parameters and photoelectrical properties of SiO₂-based multi-layer core-shell structure were systematically analyzed by various characterization methods while its degradation performance of methylene blue (MB) was also studied and discussed. The results show that when the mass ratio of AgNO₃, TEOS and TBOT to SiO₂ is 5 : 2.4 : 6 : 1, each layer of the multi-layer cored shell structure achieves the optimal coating effect. Compared with SiO₂@TiO₂ and SiO₂@Ag@TiO₂, the core-shell structure of SiO₂@Ag@SiO₂@TiO₂ photocatalyst has the best photocatalytic activity. Its photocatalytic degradation efficiency is close to 93% after simulated visible light irradiation for 45 min, and degradation efficiency keeps at 90% after 4 cycles of recycling tests.