稀土Ce改性TiO2的制备及光催化降解苯甲羟肟酸的研究

Benzohydroxamic Acid Photodegradation by Prepared Ce Modified TiO2

通过溶胶-凝胶法制备Ce改性TiO2（Ce/TiO2）复合材料,并以选矿废水中残余的浮选捕收剂苯甲羟肟酸为对象来考察Ce/TiO2的光催化降解活性;通过多种分析检测手段（X射线衍射（XRD）、X射线光电子能谱（XPS）、扫描电镜（SEM）、紫外-可见漫反射（UV-Vis DRS）等）对所合成催化剂的结构、形貌、光吸收等物理化学性能进行一系列表征。表征结果表明：相较于纯TiO2,Ce的掺杂可以有效抑制TiO2晶粒的生长,增大改性后Ce/TiO2的比表面积,从而提高其光催化活性;当掺杂量为0.20%时,其结晶度好、颗粒较均匀、具有较强的光吸收性能。苯甲羟肟酸的降解试验结果表明：当Ce的掺杂比为0.20%、煅烧温度为500℃,光催化活性最强,120 min后,苯甲羟肟酸降解率达90.98%（0.3 g·L^-1的Ce/TiO2）,矿化率达82.8%。此外,Ce/TiO2重复使用4次后,苯甲羟肟酸的光催化降解率无明显降低,表明Ce/TiO2是一种有效稳定的光催化剂。

Rare earth element Ce doped TiO2（Ce/TiO2） was synthesized by sol-gel method.Benzohydroxamic acid was used as the objective pollutant to investigate the photocatalytic activity of Ce/TiO2.The structure and physicochemical properties of prepared materials were characterized by X-ray diffraction（XRD）,X-ray photoelectron spectroscopy（XPS）,scanning electron microscopy（SEM）,ultraviolet-visible diffuse reflectance spectroscopy（UV-Vis DRS）,and so on.As a result,the doping of Ce could inhibit the crystal growth of TiO2,retain a smaller grain size,increase its specific surface area,and improve the photocatalytic activity of Ce/TiO2.The crystallinity was good when the doping ratio of Ce to TiO2 was 0.20%.The prepared Ce/TiO2 particles were more uniform,and of stronger optical absorption properties.Ce/TiO2 with the doping ratio of 0.20% calcined at 500 ℃ showed the highest photocatalytic activity to degrade benzohydroxamic acid.After 120 min,the removal rate of benzohydroxamic acid reached 90.98%（0.3 g·L^-1 of Ce/TiO2）,and 82.8% of the total organic carbon was eliminated.In addition,after four recycling runs,Ce/TiO2（0.20%） still kept high photocatalytic activity on the photodegradation of benzohydroxamic acid.