Highly enhanced photoreductive degradation of perchlorinated compounds on dye-sensitized metal/TiO2 under visible light
Highly enhanced photoreductive degradation of perchlorinated compounds on dye-sensitized metal/TiO2 under visible light
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DOI：
10.1021/es025617q
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发表时间：
2003-01-01
影响因子：
11.4
通讯作者：
Choi, W
中科院分区：
文献类型：
--
作者：
Bae, E;Choi, W
本研究报道了钌络合敏化剂和贵金属镀层改性TiO2可见光催化剂的一个例子。以三氯乙酸（TCA）和四氯化碳的光降解为探针反应，在λ > 420 nm的光照下评价了光催化剂的可见光活性。在染料敏化TiO2 （Pt/TiO2/(RuL3)-L-II）上光沉积铂纳米粒子可显著提高TCA和CCl4的降解率。当[(RuL3)-L-II] = 10 muM, [TiO2] = 0.5 g/L， Pt负载约0.2 wt %时，Pt/TiO2/(RuL3)-L-II的可见光反应性最佳。虽然在水悬浮液中没有添加电子给体来再生氧化的ru -敏化剂，但高氯化合物的光还原脱氯远远超出了初始敏化剂浓度的化学计量极限。水作为电子供体使敏化剂再生，同时产生二氧。另一方面，Pt/TiO2/(RuL3)-L-II在溶解氧存在下完全失活，原位生成的双氧逐渐减慢脱氯速率。在铂镀层上，导电带电子优先转移到02而不是CCl4和TCA。其他贵金属（Ag， Au和Pd）沉积在TiO2上，表现出比Pt/TiO2/(RuL3)-L-II更好的耐氧性，但可见光反应性较差。讨论了金属负载对可见光活性的影响及其对高效可见光光催化剂开发的意义。
This study reports an example of visible-light photocatalyst based on TiO2 modified by ruthenium-complex sensitizers and noble metal deposits. The photodegradation of trichloroacetate (TCA) and carbon tetrachloride was used as a probe reaction for evaluating the visible light activity of the photocatalyst under the illumination of lambda > 420 nm. Photodeposition of platinum nanoparticles on dye-sensitized TiO2 (Pt/TiO2/(RuL3)-L-II) drastically enhanced the degradation rate of TCA and CCl4. The visible light reactivity of Pt/TiO2/(RuL3)-L-II was optimal with [(RuL3)-L-II] = 10 muM, [TiO2] = 0.5 g/L, and Pt loading of about 0.2 wt %. Although no electron donors to regenerate the oxidized Ru-sensitizers were added in the aqueous suspension, the photoreductive dechlorination of perchlorinated compounds proceeded far beyond the stoichiometric limit of the initial sensitizer concentration. Water acted as an electron donor to regenerate the sensitizer with a concurrent production of dioxygen. On the other hand, Pt/TiO2/(RuL3)-L-II was completely inactive in the presence of dissolved oxygen and the in-situ generated dioxygen gradually decelerated the dechlorination rate. Conduction band electrons transferred to 02 in preference to CCl4 and TCA on Pt deposits. Other noble metals (Ag, Au, and Pd) deposited on TiO2 showed a better oxygen-tolerance but less visible-light reactivity than Pt/TiO2/(RuL3)-L-II. Effects of metal loading on the visible light activity and its implications for the efficient visible-light photocatalyst development are discussed.