煤基石墨烯/TiO2复合材料的制备及光催化性能

摘要

以资源丰富的褐煤为原料,经高温石墨化处理后,采用改进的Hummers法制备氧化石墨烯(GO),再以四氯化钛(TiCl4)为钛源,通过水热合成法制备煤基石墨烯/TiO2 (CRGO/TiO2)复合材料.利用扫描电镜(SEM)、能谱仪(EDS)、透射电镜(TEM)、X射线衍射仪(XRD)、低温氮气物理吸附仪、傅里叶红外光谱仪(FTIR)对复合材料的微观结构进行系统表征,并重点研究不同GO添加量下所制CRGO/TiO2复合材料对液相中罗丹明B的光催化降解性能.结果表明:以褐煤为碳质前体,TiCl4为钛源,采用水热合成法可合成具有介孔特征的煤基石墨烯/TiO2复合材料,其比表面积可达88.53～169.64m2/g,孔径主要分布在2～12nm,且随着GO添加量的增加,复合材料的孔径分布逐渐变窄.复合材料中的TiO2纳米颗粒主要以锐钛矿晶型均匀分散于层状石墨烯表面.GO添加量是影响复合材料光催化降解性能的重要因素.当GO添加量为8％时,CRGO/TiO2复合材料在可见光下对罗丹明B的降解率可达98.9％.%Graphene oxide (GO) was prepared from high temperature graphited lignite by modified Hummers method.The coal-based graphene/TiO2 composites were synthesized subsequently via hydrothermal method using four titanium chloride (TiCl4) as titanium source and graphene oxide as carbon source.The microstructure of the CRGO/TiO2 composites was characterized by scanning electron microscopy (SEM),energy dispersive spectrometer (EDS),transmission electron microscope (TEM),X-ray diffraction (XRD),low temperature nitrogen adsorption and fourier transform infrared spectrometer (FTIR).The rhodamine B (RhB) photocatalytic degradation performance in liquid phase of CRGO/TiO2 prepared at different additive amount of GO were also systematically investigated.The results show that coal-based graphene/TiO2 composites with mesoporous characteristics can be synthesized via hydrothermal method using lignite as carbonaceous precursor and TiCl4 as titanium source.The specific surface areas of CRGO/TiO2 composites are as high as 88.53～ 169.64m2/g and the pore size is mainly in the range of 2～12nm.Moreover,the pore size distribution of CRGO/TiO2 composites becomes more narrow with the increase of GO.The TiO2 particles mainly in anatase phase homogeneously distribute on the surface or layers of graphene.The additive amount of GO is an important factor affecting the photocatalytic degradation performance of composites,and the removal rate of CRGO/TiO2 for RhB can reach 98.9％ under visible light irradiation when the amount of GO is 8％.