Fluorination of ZnWO4 Photocatalyst and Influence on the Degradation Mechanism for 4-Chlorophenol
Fluorination of ZnWO4 Photocatalyst and Influence on the Degradation Mechanism for 4-Chlorophenol
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DOI：
10.1021/es801672a
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发表时间：
2008-11-15
影响因子：
11.4
通讯作者：
Zhu, Yongfa
中科院分区：
文献类型：
--
作者：
Huang, Guangli;Zhang, Shicheng;Zhu, Yongfa
采用水热法和热处理法制备了氟掺杂ZnWO 4光催化剂。阐明了氟在晶体中的存在状态，研究了氟对晶体结构、光催化活性和降解中间产物的影响。ZnWO 4晶体间隙晶格中氟的掺杂浓度可以通过退火条件来控制。掺杂后的ZnWO 4晶体结构完整，经450 ℃退火1h后，光催化活性提高了50%左右。掺氟后光催化活性的提高可能是由于掺杂后电子-空穴对的分离效率提高，导致大量空穴参与光催化过程。氟的掺杂并没有改变4-氯苯酚（4-CP）在我们的系统中的降解途径。4-CP主要转化为苯醌（BQ）、对苯二酚（HQ）和4-氯邻苯二酚（4-CC）等羟基化芳香族中间体。4-CP在粉末状Hoped ZnWO_4体系中的光降解是通过直接空穴氧化反应进行的。
The fluorine doped ZnWO4 photocatalyst was synthesized by hydrothermal synthesis and annealing treatment. The existing states of fluorine in the crystal were elucidated, and the effects of fluorine on the crystal structure, photocatalytic activity, and degradative intermediates were investigated. The doping concentration of fluorine in the interstitial lattice of ZnWO4 crystal can be controlled by the annealing conditions. The photocatalytic activity can be enhanced about 50% after the doped ZnWO4 was annealed at 450 degrees C for 1 h due to perfect crystal structure. The enhancement of photocatalytic activity after fluorine doping could be attributed to the higher separation efficiency of electron-hole pairs, which results in a large number of holes participated in the photocatalytic process. The fluorine doping does not change the degradation pathway of 4-chlorophenol (4-CP) in our system. 4-CP was mainly transformed into hydroxylated aromatic intermediates such as benzoquinone (BQ), hydroquinone (HQ), and 4-chlorocatechol (4-CC). The photodegraclation of 4-CP in powdered Hoped ZnWO4 system proceeded via direct holes oxidation reactions.