以纳米微晶纤维素为模板的酸催化水解法制备球形介孔TiO_2

以纳米微晶纤维素(NCC)为模板剂,采用酸催化水解法制备了球形介孔TiO2(SP-TiO2).并采用扫描电镜、透射电镜、X射线衍射、紫外-可见漫反射光谱和低温N2吸附-脱附等手段对其进行了表征.结果表明,所制SP-TiO2为直径100～200nm的规整球形颗粒,单个球形颗粒由粒径为10～20nm的TiO2小晶粒组成.其介孔孔径为8.2～13.5nm,且随焙烧温度的升高而增大.NCC长链结构之间羟基键合所形成的狭小空间构成的微反应器,可有效限制TiO2前驱体的生长和团聚,诱导其晶粒自组装成球形结构,并抑制由锐钛矿相向金红石相转变.600oC焙烧的SP-TiO2表现出最高的光催化活性,对苯酚降解率达89%.

Mesoporous TiO2 Spheres Prepared by an Acid Catalyzed Hydrolysis Method Using Nanocrystalline Cellulose as Template

Mesoporous nanosize TiO2 spheres(SP-TiO2) were prepared using natural polymer nanocrystalline cellulose(NCC) as template.Scanning electron microscopy,transmission electron microscopy,X-ray diffraction,ultraviolet-visible diffuse reflection spectroscopy,and N2 adsorption-desorption were used for the characterization of the SP-TiO2 photocatalyst.The results showed that SP-TiO2 was uniform in size with a diameter of 100-200 nm.SP-TiO2 was composed of smaller crystal particles(10-20 nm).The average mesoporous pore diameter of SP-TiO2 was 8.2-13.5 nm,which increased with increasing calcination temperature.A nano-scale reactor that was formed by bonding between the hydroxyl groups of NCC long-chain can inhibit the growth and aggregation of the TiO2 precursor,promote its self-assembly into spherical structure,and inhibit the phase transformation from anatase to rutile.SP-TiO2 prepared at 600 oC exhibited the highest activity with the phenol degradation percentage of 89%.