P123对rGO/m-TiO2薄膜微观结构及光催化性能的影响

以自制氧化石墨烯（GO）分散液和加入一定量三嵌段共聚物PEO₂₀-PPO₇₀-PEO₂₀（P123）模板剂的TiO₂前驱体溶胶为原料，用交替浸渍-提拉结合热处理和紫外灯辐照还原法在玻璃基底上制备还原氧化石墨烯/介孔TiO₂（rGO/m-TiO₂）多层膜.通过X-射线衍射（XRD）、拉曼光谱（Raman）、扫描电子显微镜（SEM）、比表面积（BET）对多层膜进行表征分析.研究了模板剂P123加入量对多层膜的晶体结构、比表面积、形貌、孔径分布情况、吸附性能、光催化性能的影响.分别在紫外光及太阳光下评价rGO/m-TiO₂多层膜对土霉素（OTC）的光催化降解效果；在紫外光条件下，研究了多层膜对OTC的光催化降解机理.结果表明：P123的引入不会引起TiO₂晶体结构的变化；适量P123的引入可以优化多层膜的孔结构，增大比表面积、提高其吸附性能，进而提高薄膜的光催化性能；rGO/TiO₂（5wt% P123）薄膜60min对OTC的吸附率达51.2%，紫外光照射135min，降解率达到90.9%；太阳光照射50min，降解率达到91.5%.在降解OTC过程中，羟基自由基（·OH）起主要作用，路径以与·OH相关的羟基化反应和仲羟基氧化反应为主.

Effect of P123 on the microstructure and photocatalytic activity of rGO/mesoporous TiO2 films

In this study, self-made GO dispersion liquid and TiO₂ precursor sol with a certain amount of the triblock copolymer, (polyethylene oxide, PEO) ₂₀-(polypropylene oxide, PPO) ₇₀-(PEO)₂₀ (P123) were used as raw materials. The reduced graphene oxide/mesoporous TiO₂ (rGO/m-TiO₂) multilayer films were prepared on glass substrates by alternating dipping-coating combined with heat treatment and ultraviolet lamp irradiation reduction method. The multilayer film was characterized by X-ray diffraction (XRD), Raman spectroscopy (Raman), scanning electron microscopy (SEM), and specific surface area (BET) analysis. The effects of the amount of templating agent P123 on the crystal structure, specific surface area, morphology, pore size distribution, adsorption performance, and photocatalytic performance of the multilayer film were investigated. The photocatalytic degradation of oxytetracycline (OTC) by multilayer film multilayer film was evaluated under ultraviolet light and sunlight. The photocatalytic degradation mechanism was studied under ultraviolet light. The results showed that the crystal structure of TiO₂ does not change after adding P123. The optimized pore structure and large specific surface area can be obtained by the introduction of appropriate P123, which are conducive to the adsorption capacity and the photocatalytic activity. The adsorption efficiency of rGO/TiO₂ (5wt%P123) film on OTC reached 51.2% for 60min, and the degradation rate of ultraviolet irradiation reached 90.9% for 135 min.The degradation rate reached 91.5% after 50min of sunlight exposure. During the degradation of OTC, hydroxyl radical (·OH) plays a major role in photocatalysis, and hydroxylation and secondary hydroxyl oxidation are the main reaction paths.