掺杂Ce的TiO_2纳米粒子的光致发光及其光催化活性  

Photoluminescence of Ce Doped TiO_2 Nanoparticles and Their Photocatalytic Activity

作　　者：井立强[1] 孙晓君[2] 蔡伟民[2] 李晓倩[2] 付宏刚[1] 候海鸽[1] 范乃英[1] 

机构地区：[1]黑龙江大学化学化工学院,哈尔滨150001 [2]哈尔滨工业大学环境科学与工程系,哈尔滨150001

出　　处：《化学学报》2003年第8期1241-1245,共5页Acta Chimica Sinica

摘　　要：采用sol gel法制备了纯的和掺杂不同量Ce的TiO2 纳米粒子 ,并利用XRD ,TEM ,BET ,XPS和PL光谱对样品进行表征 ,主要考察焙烧温度和含量对掺杂Ce的TiO2 纳米粒子性质以及光催化降解苯酚活性的影响 ,并探讨了Ce的掺杂对TiO2相变的作用机制以及PL光谱与光催化活性的关系 .结果表明 ,掺杂的Ce4+ 没有进入到TiO2 晶格中 ,而是以小团簇的CeO2化学态均匀地弥散在TiO2 纳米粒子中 ,这可能导致了Ce的掺杂对TiO2 的相变有很大的抑制作用 ;Ce的掺杂没有引起新的光致发光现象 ,而适量Ce的掺杂能够降低TiO2 纳米粒子PL光谱的强度 ,这是因为掺杂的Ce4+ 易于捕获光生电子而生成Ce3 + ;60 0℃处理的掺杂Ce的TiO2 纳米粒子表现出较高的光催化活性 ,这说明 60 0℃是比较合适的焙烧温度 .而掺杂不同量Ce的TiO2 样品的光催化活性顺序是 :3mol % >4mol% >2mol% >5mol% >1mol% >0mol% ,这与它们的PL光谱强度的顺序是相反的 ,即PL光谱强度越低 ,其光催化活性越高 .这说明PL光谱与其光催化活性间有着必然的联系 ,这是因为掺杂剂Ce4+ 能够捕获光生电子 ,在光致发光过程中使PL光谱强度下降 。In this paper, TiO2 nanoparticles pure and doped with varying content of Ce were prepared by a sol-gel process using Ti(OC4H9)(4) as raw material and characterized by XRD, TEM, BET, XPS and PL spectra. We mainly investigated the effects of calcining temperature and Ce content on the properties and the photocatalytic activity for degrading phenol of the TiO2 nanoparticles. The relationships between PL spectra and photocatalytic activity as well as the mechanisms of Ce doping on TiO2 phase change were also discussed. The results show that Ce4+ did not enter into the crystal lattices of TiO2 and was uniformly dispersed into TiO2 as the form of CeO2 with small size, which possibly made Ce dopant have a great inhibition on TiO2 phase change; Ce dopant did not give rise to a new PL signal, but an appropriate content of Ce could make the intensity of PL spectra down, which was attributed to the ability of Ce4+ to easily capture the photoinduced electrons to form Ce3+; Ce doped TiO2 nanoparticles calcined at 600 degreesC exhibited higher photocatalytic activity, indicating that 600 degreesC was an appropriate calcination temperature. The order of the photocatalytic activity of TiO2 samples doped with varying content of Ce is as follows: 3 mol% > 4 mol% > 2 mol% > 5 mol% > 1 mol% > 0 mol%. which is opposite to the order of their PL intensity, namely, the weaker the PL intensity, the higher the photocatalytic activity, demonstrating that there are certain relationships between PL spectra and photocatalytic activity. This could be explained by the fact that the dopant Ce4+ can readily capture the photoinduced electrons, which not only makes the intensity of PL spectra down during the process of photoluminescence but also improves the oxidation speed of organic pollutants during the process of photocatalytic reaction.

关 键 词：掺杂 CE TIO2纳米粒子 光致发光 光催化活性 苯酚 SOL-GEL法 二氧化钛 半导体材料 制备 

分 类 号：O643.3[理学—物理化学]