摘要
用稀土铈改性TiO2涂附于姻锡氧化物导电玻璃基体上，加热到450℃保温30min得到半导体工作电极．用循环伏安（CV）测试表明在＋1．35～＋4．0V（vs．SCE）电位间出现氧化峰，该氧化峰对应两个反应：[Ce^3＋O2^2-]defect^-＋H^＋→[Ce^4＋O2^2-]和OH^-＋h^＋→ ·OH，这两个反应都消耗空穴且相互竞争。由于第一个反应较容易进行，激发态的空穴优先复合缺陷[Ce^3＋O2^2-]defect^-而不是迁移到半导体表面，因此[Ce^3＋O2^2-]defect^-＋H^＋→[Ce^4＋O2^2-]反应是主要反应，而OH^-＋h^＋→ ·OH反应却很难进行。在极化电位-0．8～-1．2V之间，发生的还原反应是O2＋e^-→O2^-，激发态电子迁移到材料表面与吸附与表面的氧分子发生还原反应。电子自旋共振（ESR）测试表明只有在紫外光照下有．OH信号微弱的而O2^-在黑暗、可见光、紫外光条件下都能捕捉到信号，这个测试结论与电化学分析结果一致。
TiO2 was modified with rare earth cerium （Ce） and then coated on indium tin oxide （ITO） conductive glass substrate. The coated substrate was sintered at 450℃ for 30 min and semiconductor working electrode was obtained. Cyclic voltammetry （CV） tests indicate that when the polarization potential is within the range of＋ 1.35-＋4.0V （vs. SCE）, there lies oxidation reaction peaks on the CV curve, which correspond to two reactions： [Ce^3＋O2^2-]defect^-＋H^＋→[Ce^4＋O2^2-] and OH^-＋h^＋→ ·OH; these two reactions are both hole （h^＋） consumptive and are competitive to each other. Since the former is easier to occur, the excited holes （h^＋） take precedence to recombine with [Ce^3＋O2^2-]defect^- rather than migrating to the semiconductor surface, and consequently [Ce^3＋O2^2-]defect^-＋H^＋→[Ce^4＋O2^2-] is the major reaction, while the reaction OH^-＋h^＋→ ·OH is hard to occur. Within the polarization potential range of -0.8- - - 1.2V, there lies the reduction reaction of O2＋e^-→O2^-, which is the reaction between the excited electrons （e） that have migrated to the material surface and the oxygen adsorbed on the material surface. Electron spin resonance （ESR） tests indicate that there are very weak -OH signals only under UV irradiations while considerable O2^- signals are captured under any of dark, visible light and UV irradiation; this test result is in fully agreement with the electrochemical analysis results.
出处
《功能材料》
EI
CAS
CSCD
北大核心
2007年第A07期2421-2424,共4页
Journal of Functional Materials
关键词
二氧化钛
循环伏安
电子自旋共振
cerium
TiO2
cyclic voltammetry （CV）
electron spin resonance
