摘要
以钛酸四丁酯为钛源、氢氟酸为氟源、乙醇为溶剂,采用溶剂热法合成了氟化改性的TiO2空心微球,并利用XRD、FESEM、FTIR、XPS等手段对氟化TiO2微球的晶体结构、形貌、分子基团以及元素形态等性质进行了表征,同时将TiO2微球应用于光催化降解甲基橙溶液。结果表明:氟化TiO2空心微球由奥斯瓦尔德熟化过程获得,其中TiO2以锐钛矿存在,氟以化学吸附态存在于TiO2的表面,形成≡Ti-F基团。相比纯TiO2,氟化TiO2空心微球光催化活性有很大提高,对初始浓度为20 mg·L-1的甲基橙溶液进行光催化降解30 min,其降解率达到98%。氟化改性TiO2空心微球光催化活性的提高是源于TiO2独特的空心微球结构以及TiO2表面≡Ti-F基团的存在。TiO2表面≡Ti-F基团有很强的吸电子能力,抑制了光生电子与空穴的复合,同时有利于羟基自由基的产生。
Using tetrabutyl orthotitanate as Ti source, hydrofluoric acid as F source and ethanol as solvent, well crystallized anatase-phase F-modified TiO2 hollow microspheres have been synthesized via a solvothermal process. The structure and properties of the resulting samples were characterized by XRD, SEM, FTIR, XPS. The results indicated that the fluorizated TiO2 hollow microspheres had an anatase phase, the fluorine atoms were mainly distributed on the surface of TiO2, and existed in forms of chemical-adsorption. Hollow anatase TiO2 mlcrospheres were achieved by Ostwald ripening under solvothermal conditions. Compared to pure titania, the fluorizated TiO2 hollow microspheres showed a much higher degradation efficiency, and degradation rate of which can be up to 98% during the photodegradation of methyl orange with the initial concentration of 20 mg. L-1 for 30 minutes. The mechanism for the great improvement for photocatalytic activity can be attributed to the unique structure of hollow microsphere and the fluorine modification, because the strong electron withdrawing ability of the surface -=Ti-F groups reduces the recombination of photogenerated electrons and holes, and enhances the formation of free OH radicals.
出处
《无机化学学报》
SCIE
CAS
CSCD
北大核心
2013年第10期2133-2139,共7页
Chinese Journal of Inorganic Chemistry
基金
国家自然科学基金(No.51202052
No.91023030)
安徽省国际科技合作计划(No.10080703017)资助项目
关键词
二氧化钛
氟化
空心微球
光催化
titanium dioxide
fluorine-modification
hollow microspheres
photocatalysis
