TiO_(2)/石墨烯基复合材料的制备及光催化降解染料研究

Preparation of TiO_(2)/graphene-based composites andphotocatalytic degradation of dyes

采用改进Hummers法制备氧化石墨烯(GO)和水解法制备的TiO_(2)及溶剂热法制备了还原氧化石墨烯(rGO)和一系列不同浓度的rGO/TiO_(2)纳米复合材料(0、5%、10%、15%、20%质量分数),并对合成产物进行SEM、XRD、XPS、DRS、Raman等表征,研究不同实验条件下纯TiO_(2)和rGO/TiO_(2)复合催化剂对亚甲基蓝染液(MB)的降解效果。结果表明,复合光催化剂中TiO_(2)主要为锐钛矿相,溶剂热合成引入的还原氧化石墨烯(rGO)对TiO_(2)的物相没有产生影响,rGO的引入使得rGO/TiO_(2)吸收带发生一定红移,TiO_(2)禁带宽度由3.23降低至3.09 eV;合成的(15%质量分数)rGO/TiO_(2)具有最佳的光催化效果,光催化活性最高,在100 W高压汞灯照射下70 min对20 mg/L的亚甲基蓝染料的降解率达97.6%;在500 W氙灯光源下照射70 min对20 mg/L亚甲基蓝染料的降解率达到93.2%,(15%质量分数)rGO/TiO_(2)复合光催化剂具有良好的光催化降解性及循环稳定性,5次循环光催化降解后,rGO/TiO_(2)有86.1%的降解效率。表现出了优异的吸附和光催化性能,这可为光催化处理废液提供了一种有效的方法。

Reduced graphene oxide(rGO)and a series of rGO/TiO_(2) nanocomposites with different concentrations(0,5%,10%,15%,and 20 wt%)were prepared by the modified Hummers'method for the preparation of graphene oxide(GO)and TiO_(2) by hydrolysis and solvent-thermal method.The synthesized products were characterized by SEM,XRD,XPS,DRS,Raman,etc.,to investigate the degradation effect of pure TiO_(2) and rGO/TiO_(2) composite catalysts on methylene blue dye(MB)under different experimental conditions.The results showed that the TiO_(2) in the composite photocatalyst was mainly in anatase phase,and the reduced graphene oxide(rGO)introduced by solvothermal synthesis had no effect on the physical phase of TiO_(2).The introduction of rGO made the absorption band of rGO/TiO_(2) red-shifted to a certain extent,and the width of the TiO_(2) forbidden band was reduced from 3.23 to 3.09 eV.The synthesized(15 wt%)rGO/TiO_(2) has the best photocatalytic effect and the highest photocatalytic activity,and the degradation rate of 20 mg/L methylene blue dye under 100 W high-pressure mercury lamp irradiation for 70 min reaches 97.6%,and the degradation rate of 20 mg/L methylene blue dye under 500 W xenon lamp irradiation for 70 min reaches 93.2%.The composite photocatalysts of(15 wt%)rGO/TiO_(2) have the good photocatalytic degradation and cyclic stability.rGO/TiO_(2) had a degradation efficiency of 86.1%after 5 cycles of photocatalytic degradation.The rGO/TiO_(2) composite photocatalyst show excellent adsorption and photocatalytic performance,which can provide an effective method for the photocatalytic treatment of waste liquids.