Visible light-induced degradation of carbon tetrachloride on dye-sensitized TiO2
Visible light-induced degradation of carbon tetrachloride on dye-sensitized TiO2
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DOI：
10.1021/es001245e
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发表时间：
2001-03-01
影响因子：
11.4
通讯作者：
Lee, HI
中科院分区：
文献类型：
--
作者：
Cho, YM;Choi, WY;Lee, HI
研究了三（4，4 '-二羧基-2，2'-联吡啶）钌（II）配合物敏化的TiO 2光催化剂在可见光照射下降解四氯化碳（CCl 4）的应用。CCl_4脱氯的量子产率约为10（-3）。溶解的O-2的存在下，由于其竞争导带电子的四氯化碳的脱氯速率降低。由于光敏剂在TiO 2表面的吸附对pH有很强的依赖性，因此光解速率取决于pH，在pH接近3时达到最大降解速率。一个两个网站的Langmurian模型成功地描述了敏化剂在二氧化钛颗粒上的吸附。在[TiO 2] = 0.5 g/L时，在10 μ M的添加敏化剂浓度下实现单层覆盖。然而，CCl 4的光解速率在敏化剂表面覆盖率为0.3单层时表现出最大值。由于光致电子注入逐渐耗尽活性敏化剂分子和TiO 2，寻求牺牲电子供体来再生敏化剂。2-丙醇作为电子供体是有效的，在本（RuL 3）-L-II/TiO 2/CCl 4系统，这表明没有迹象表明减速的脱氯率高达6小时的照射。
This study investigated an application of TiO2 photocatalyst sensitized with tris(4,4'-dicarboxy-2,2'-bipyridyl)ruthenium(II) complex to CCl4 degradation under visible light;irradiation, By injecting electrons from the photoexcited:sensitizer to the conduction band, the sensitized TiO2 degraded CCl4 under the irradiation of lambda > 420 nm. The quantum yield of CCl4 dechlorination was about 10(-3). The dechlorination rate of CCl4 was reduced in the presence of dissolved O-2 due to its competition for conduction band electrons. The photolysis rate was dependent on pH due to the strong pH dependence of the sensitizer adsorption on TiO2 surface with a maximum degradation rate achieved at pH similar to3. A two-site Langmurian model successfully described the adsorption of the sensitizer on TiO2 particles. The monolayer coverage was achieved at the added sensitizer concentration of 10 muM at [TiO2] = 0.5 g/L. However, the photolysis rate of CCl4 showed a maximum at a sensitizer surface coverage of 0.3 monolayer. Since the photoinduced electron injection gradually depleted active sensitizer molecules an TiO2, sacrificial electron donors to regenerate the sensitizer were sought. 2-Propanol as an electron donor was efficient in the present (RuL3)-L-II/TiO2/CCl4 system, which showed no sign of deceleration in the dechlorination rate up to 6 h of irradiation.