喷雾燃烧热分解制备Cr掺杂TiO_2纳米粒子的可见光催化性能

Visible-light Photocataltic Activity of Cr-doped TiO_2 Nanoparticles Synthesized by Flame Spray Pyrolysis

采用一步喷雾燃烧热解法制备了Cr掺杂TiO2纳米粒子,研究了Cr掺杂对样品微结构、吸光特性和可见光催化活性的影响.结果表明:增加Cr掺杂量抑制锐钛矿相的形成,同时促进金红石相的形成.在低Cr掺杂量下(≤1%),Cr主要以Cr3+的形态进入TiO2晶格,而Cr掺杂量过大时,易于形成Cr2O3团簇.光催化降解2,4-二氯苯酚结果表明,适量的Cr3+掺杂可以有效地提高TiO2的可见光催化活性,获得最高光催化活性的Cr3+掺杂量为1at%.样品可见光催化活性的提高主要与Cr掺杂引起的可见光吸收增强、晶相组成改善以及光生电子和空穴传输效率提高有关.

Cr-doped TiO2 nanoparticles were synthesized by one-step flame spray pyrolysis technique. The effects of Cr^3＋ doping on the microstructure, light absorption property, and photocatalytic activity of the samples were investigated. It is found that increasing Cr^3＋ concentration restrains the formation of anatase and simultaneously favors the formation of rutile. At low concentration （≤1%）, Cr is mainly incorporated into the crystal lattice of TiO2 in the form of Cr^3＋, while high Cr concentration promotes the formation of Cr2O3 clusters. The result of photocatalytic degradation of 2,4-dichlorophenol demonstrates that appropriate Cr^3＋ doping can evidently enhance the visible-light photocatalytic activity of TiO2. The optimal Cr^3＋ concentration to obtain the highest photocatalytic activity is 1at%. The improvement of visible-light photocatalytic activity derived from Cr doping is mainly related to the enhancement of visible light absorption, appropriate crystalline composition, and improved transfer efficiency of photogenerated electrons and holes.