Electron spin resonance spin-trapping detection of radical intermediates in N-doped TiO2-assisted photodegradation of 4-chlorophenol
Electron spin resonance spin-trapping detection of radical intermediates in N-doped TiO2-assisted photodegradation of 4-chlorophenol
复制标题
N 掺杂 TiO2 辅助 4-氯苯酚光降解中自由基中间体的电子自旋共振自旋捕获检测。
DOI：
10.1021/jp055279q
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发表时间：
2006-02-23
影响因子：
3.3
通讯作者：
Zhao, JC
中科院分区：
文献类型：
--
作者：
Fu, HB;Zhang, LW;Zhao, JC
以5，5-二甲基-1-吡咯啉-N-氧化物为自旋捕获剂，采用电子自旋共振（ESR）自旋捕获技术，对4-氯苯酚（4-CP）/N掺杂TiO（2）水悬浮液在紫外或可见光照射下产生的自由基中间体进行了原位检测。ESR测量首次提供了N掺杂TiO（2）可见光催化分解4-CP的活性物种（（*）OH和O（2*-））的直接证据，有力地表明N掺杂TiO（2）粉末体系中有机化合物的光催化反应是通过表面氧还原或水氧化的中间体进行的，而不是通过与在N诱导的中间带隙能级处捕获的空穴的直接反应。这些结果对TiO（2-x）N（x）催化剂氧化粉末的评价具有重要意义。
The electron spin resonance (ESR) spin-trapping technique using 5,5-dimethyl-1-pyrroline-N-oxide as the spin-trap reagent has been applied to detect free radical intermediates generated during in situ ultraviolet or visible irradiation of aqueous 4-chlorphenol (4-CP)/N-doped TiO(2) suspensions. ESR measurements gave the first direct evidence that the active species ((*)OH and O(2*-)) are responsible for the photodecomposition of 4-CP over N-doped TiO(2) under visible-light irradiation, strongly suggesting that the photocatalytic reaction of organic compounds in powdered N-doped TiO(2) systems proceed via surface intermediates of oxygen reduction or water oxidation, not via direct reaction with holes trapped at the N-induced midgap level. These results have important implications for the evaluation of the oxidative powder of TiO(2-x)N(x) catalysts.