纳米TiO_2光催化材料离子掺杂的正电子湮没研究  

Positron annihilation of nanometer TiO_2 photocatalytic material doped with metal ions

作　　者：陈建华[1] 邓文[2] 

机构地区：[1]广西大学资源与环境学院,广西南宁530004 [2]广西大学物理科学与工程技术学院,广西南宁530004

出　　处：《工业催化》2008年第12期7-12,共6页Industrial Catalysis

基　　金：国家自然科学基金资助项目(20466001)

摘　　要：采用正电子湮没技术研究了13种金属离子掺杂对纳米TiO2光催化材料缺陷的影响,并讨论了离子掺杂对TiO2光催化材料平均电子密度和光催化活性的影响。结果表明,纳米TiO2光催化材料的缺陷主要是氧空位、孪晶界、位错和金属空位等。正电子湮没谱的分析表明,Fe3+、W6+和La3+高价态离子的掺杂降低纳米TiO2的平均电子密度,低价态的Zn2+、Cu2+、Pb2+、Mn2+、Co2+和Ag+掺杂增大了纳米TiO2的平均电子密度,Al3+、V5+、Ni2+和Cr3+的掺杂对纳米TiO2平均电子密度没有影响。纳米TiO2的离子掺杂寿命谱与光催化活性之间关系分析表明,Pb2+、La3+、Cr3+和Co2+掺杂时,材料中自由体积缺陷的形成不利于TiO2光催化活性的提高,而Fe3+、W6+、La3+、Cu2+、Mn2+、Ag+、Al3+、V5+和Ni2+掺杂时,则有利于TiO2光催化活性的提高。The effects of doping with different metal ions on the defects of nanometer TiO2 photocatalytic material and its mean electron density and photoactivity were investigated by means of positron annihilation technique. The results showed that the defects of nanometer TiO2 photocatalytic material were mostly oxygen vacancy, twin crystal boundary, dislocation and metal vacancy. The Doppler energy spectra for TiO2 positron annihilation indicated that doping of higher valence ion （ Fe3＋ , W6＋ and La3＋ ） decreased the mean electron density of nanometer TiO2, and that of lower valence ions（ Zn2＋ , Cu2＋ , Pb2＋ , Mn2＋ , Co2 ＋, and Ag ＋ ） increased the mean electron density of nanometer TiO2. Doping of Al3 ＋ , V5＋ , Ni2 ＋ , Cr3 ＋ had no influence on the mean electron density of nanometer TiO2. The correlation between Doppler energy spectra for TiO2 positron annihilation and the photocatalytic activity indicated that formation of free volume defects by doping of Pb2＋ , La3＋ , Cr3 ＋ , Co2＋ ions was disadvantageous to enhancement of the photocatalytic activity; formation of free volume defects by doping of Fe3＋ , W5＋ , La3＋ , Cu2＋ , Mn2＋ , Ag ＋ , Al3＋ , V5＋ , Ni2＋ ions was advantageous to enhancement of the photocatalytic activity.

关 键 词：催化化学 离子掺杂 纳米TIO2 正电子湮没 光催化 

分 类 号：TB383[一般工业技术—材料科学与工程]