介孔RGO/TiO_2复合光催化材料的制备及光催化性能

Preparation and Photocatalytic Properties of Mesoporous RGO/TiO_2 Composites

采用溶胶–凝胶法,以氧化石墨烯(GO)、钛酸四丁酯(TBT)为原料,聚乙烯吡咯烷酮(PVP)为结构引导剂,柠檬酸为水解抑制剂和表面活性剂原位合成不同GO含量的介孔氧化石墨烯/二氧化钛复合材料(GO/TiO_2),再经过紫外灯辐照还原获得介孔还原氧化石墨烯/二氧化钛复合材料(RGO/TiO_2)。通过X射线衍射(XRD)、透射电镜(TEM)、比表面积(BET)、紫外–可见漫反射(UV-Vis DRS)和荧光光谱(PL)对样品进行分析表征,研究了RGO/TiO_2的形貌、孔径分布情况,RGO的引入对光生电子–空穴对寿命、吸附性能、光催化性能的影响。分别在紫外光和太阳光条件下评价了复合材料的光催化性能,并在紫外光条件下,对催化剂进行了多次回收循环测试。测试结果表明:TiO_2均匀地生长于RGO表面,RGO/TiO_2为介孔材料;RGO的引入可以有效地抑制光催化剂中光生–电子空穴对的复合,提高吸附性能和光催化性能,7wt%RGO/TiO_2显示出对甲基橙的最佳吸附效果;5wt%RGO/TiO_2对甲基橙具有最佳光催化效果和稳定的催化活性,经过4次循环后,紫外光照50 min,对甲基橙的降解率仍能达到首次降解效率的90%以上。

A series of mesoporous graphene oxide/TiO2 composites（GO/TiO2） with different mass fractions of graphene oxide（GO） were synthesized by an in-situ synthesized Sol-Gel step using GO,tetrabutyl titanate（TBT） as precursors,polyvinylpyrrolidone（PVP） as frame developing agent and citric acid as hydrolysis inhibitor and surfactant. Afterwards,mesoporous reduced graphene oxide/TiO2（RGO/TiO2） composites were obtained by ultraviolet radiation reduction method. The composites were characterized by X-ray diffraction（XRD）,Transmission electron microscopy（TEM）,Brunauer-Emmett-Teller（BET）,UV-visible diffuse reflectance spectroscope（UV-Vis DRS）,and photoluminescence（PL） spectroscopy technology. The morphology and pore size distribution of RGO/TiO2 and the effects of RGO on the lifetime of photogenerated electron-hole pairs,adsorption capacity and photocatalytic activity of composite photocatalysts were investigated. The photocatalytic activity was evaluated under ultraviolet light and sunlight irradiation. Then the recovery test was studied under ultraviolet light irradiation. Results show that TiO2 nanoparticles are well dispersed on the surface of the RGO sheets and RGO/TiO2 composites are mesoporous materials. The introduction of RGO effectively inhibits the recombination of photogenerated electron-hole pairs and improves the adsorption capacity and photocatalytic activity of composites. The 7wt% RGO/TiO2 shows the best adsorption capacity for methyl orange. And 5wt% RGO/TiO2 shows the best and stable photocatalytic activity,after four recovery test,its photocatalytic degradation of methyl orange under ultraviolet light irradiation for 50 min exceeded 90% of the first test.