化学学报 ›› 2001, Vol. 59 ›› Issue (7): 1072-1077. 上一篇    下一篇

研究论文

金离子掺杂对二氧化钛光催化性能的影响

李芳柏;李湘;李新军;万洪富   

  1. 广东省农业环境综合治理重点实验室;广东省生态环境与土壤研究所;香港理工 大学土木与结构工程系;华南理工大学化工学院应用化学系
  • 发布日期:2001-07-15

Effect of ggold ion doping on the photo-catalytic properties and photo-activity of TiO2

Li Fangbai;Li Xiang;Li Xinjun;Wan Hongfu   

  • Published:2001-07-15

利用高压钠灯作光源,在Au^3+-TiO2悬浮溶液中,通过紫外-可见吸光度与TOC测定证实亚甲基蓝能被快速脱色降解。金离子掺杂可大大提高TiO2的光催化活性,金离子的最佳掺杂摩尔分数为0.5%。通过表征催化剂的晶型,化学组成,荧光光谱,紫外-可见吸收光谱,电场诱导表面光电压谱,提示金离子改性的机理,紫外-可见吸收光谱证实金离子掺杂可增强催化剂在可见光区域的吸收能力,由于产生金杂质能级,金离子改性TiO2能被可见光激发。适量的金杂质能降低催化剂的荧光发射强度与电场诱导表面光电压谱强度。根据不同金离掺杂摩尔分数,荧光发射强度与电场诱导表面光电压谱强度从弱到强的排序与光催化活性比强到弱的排序是一致的。

关键词: 金离子, 掺杂, 可见光, 表面光电压谱, 催化活性, 有机污染物, 降解, 亚甲兰, 二氧化钛, 光催化

Methylene Blue (MB) undergoes rapid mineralization in aqueous TiO2 dispersions with or without doping with gold ion upon radiation with visible light (high-pressure sodium lamp). UV-visible absorption and TOC measurement were employed to disclose details of decolorization and mineralization. The presence of gold ion in TiO2 greatly enhaniced their photo-activity. The optimum molar content of gold ion doping was 0.5%. Investigation of crystal structure, chemical components, optical absorption properties, photoluminescence emission spectra and photo-voltage properties disclosed the mechanism of gold ion doping. UV-visible absorption spectra showed that the optical absorption increased in the visible region. Owing to gold impurity energy level, it is possible for gold ion doped TiO2 to be excited by visible light (E<3.2 eV). Gold impurities also lead to decrease photoluminescence (PL) emission and electron-field-induced surface photo-voltage spectra (EFISPS) and hinder the recombination of electron/hole. The order of EFISPS intensity and PL intensity (from weak to strong) had a good agreement with that of photo-activity (from strong to weak).

Key words: GOLD ION, DOPE, VISIBLE LIGHT, CATALYTIC ACTIVITY, ORGANIC POLLUTANTS, DEGRADATION, METHYLENUM CAERULEUM, TITANIUM DIOXIDE, PHOTOCATALYSIS

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