掺杂锡的纳米二氧化钛的合成、表征及光催化性能

以Ti(OC4H9)4和SnCl4.5H2O为原料,乙醇为溶剂,离子液体1-丁基-3-甲基四氟硼酸咪唑盐([Bmim][BF4])为表面活性剂,12%的氨水为沉淀剂,采用共沉淀法合成了不同形态的掺杂锡的二氧化钛。利用X-射线粉末衍射仪(XRD)、场发射扫描电镜(FESEM)、同步热分析仪(TG-DSC)、紫外—可见吸收光谱仪(UV-Vis)、比表面积孔隙度分析仪(BET)和能量色散X射线光谱仪(EDS)表征所合成材料的结构、形貌、热稳定性、光学性能、比表面积。Sn掺杂后各样品在紫外和可见光区的吸收能力均有不同程度地增强。与未掺杂TiO2的吸收带边相比,Sn掺杂TiO2的吸收带边分别红移了约35 nm,从而提高了光催化降解甲基橙的活性。为了评估产品的光催化性能,进行了掺杂锡的纳米二氧化钛对甲基橙的光催化降解实验,实验结果表明在2 mL离子液体中合成掺杂锡为7%的纳米二氧化钛对甲基橙的光降解具有最好的催化作用。光照90 min对甲基橙的降解率就达到了97%以上,大幅度提高了TiO2的可见光催化活性,这是因为有效抑制了光生电子和空穴的复合,也明显降低了TiO2的禁带宽度。

Sn-doped TiO2 Nano-materials: Synthesis, Characterization and Photocatalytic Activity

The Sn-doped TiO2 nanomaterials were successfully prepared using Co-precipitation method with ethanol as solvent,1-butyl-3-methy limidazolium tetrafluoroborate() as surfactant,tetrabutyl titanate(Ti(OC4H9)4)and tin(IV) chloride pentahydrate(SnCl4 ·5H2O) as reaction precursor,ammonia as precipitation agent.The structure,morphology,thermodynamic stability,optical property and surface area of the synthesized Sn-doped TiO2 nanocrystals were characterized by XRD,FESEM,TG-DSC,UV-Vis and BET.UV-vis experiments results show red-shift absorption of 35 nm in comparison with pure TiO2,leadinng to good photocatalytic activity.The experimental results indicated that the Sn-doped TiO2 prepared in the alcohol and ionic liquid system trend to form the spherical anatase nanocrystals.The liquid-phase photocatalytic degradation of methyl orange was used to test the photocatalytic activity of the synthesized materials.It was found that the sample Sn-doped TiO2 with the 7% concentration prepared in 2 mL ionic liquid showed the better photoactivity.Under UV irradiation for 90 min,TiO2 doped with 7% Sn have the better photodecomposition efficiencywith up to 97% than other samples,which are contributed not only to inhibit the recommbination of photoproduced electrons and holes,but also narrow the band gap of TiO2.