用吸附相反应技术制备弱光响应的铈掺杂TiO_2复合光催化剂

Preparation of weak-light-driven TiO_2 composite photocatalysts by adsorption phase synthesis

为拓展多相光催化的实际应用和满足环境治理的严格要求,利用吸附相反应技术设计并制备了弱紫外光响应高效的TiO_2多组分催化剂。借助透射电子显微镜、高分辨率透射电子显微镜和X射线衍射分析了不同焙烧温度下铈离子掺杂量对催化剂形貌的影响,并结合光致发光光谱和弱光降解甲基橙过程,探索了催化剂结构变化对光生载流子复合率和弱光催化活性的影响。结果表明,当掺杂量较低(小于0.10%)时,铈离子掺入引起TiO_2晶格膨胀,从而引入光生载流子的浅能级捕获中心,提升了催化活性;在较高掺杂量(0.20%以上)时,铈离子掺入抑制了TiO_2结晶,催化剂中大量无定形TiO_2严重抑制了其活性;焙烧温度越高,铈离子掺杂量对催化剂结构和活性的影响越显著;降解高浓度甲基橙时,催化性能最好的催化剂的活性是商用P25的2倍多。

In order to expand the practical application of photocatalysis and meet the increasingly stringent environmental requirements,weak UV light-driven TiO2 composite photocatalysts with high performance were prepared by adsorption phase synthesis.Transmission electron microscopy,high resolution transmission electron microscopy and X-ray diffraction were employed to characterize the morphology of different catalysts.Combining the results by photoluminescence spectra with the degradation of methyl-orange excited by weak UV light,the influence of the catalyst structure on the recombination of photogenerated carriers and its photocatalytic activity was explored.The results indicate that Ce^（3＋） doping with low doping content（less than 0.10%） leads to the lattice expansion of TiO2 and introduces some shallow capture sites for photogenerated carriers,thus enhancing the activity of the catalyst.At high doping content（≥ 0.20%）,Ce^（3＋）doping greatly inhibites the crystallization of TiO2 and causes a large amount of amorphous TiO2 in the catalysts,which significantly depresses the photocatalytic activity illuminated under weak UV light.The higher the calcination temperature is,the more obvious the effect of Ce^（3＋）doping on the structure and activity of the catalysts is.For photodegradation for methyl-orange with high concentration,the degradation efficiency of the optimum catalyst is two times higher than that of the commercial photocatalyst P25.