Effects of nano-Ag particles loading on TiO2 photocatalytic reduction of selenate ions
Effects of nano-Ag particles loading on TiO2 photocatalytic reduction of selenate ions
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DOI：
10.1016/s1385-8947(03)00103-7
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发表时间：
2003-09-15
影响因子：
15.1
通讯作者：
Amal, R
中科院分区：
文献类型：
--
作者：
Tan, TTY;Yip, CK;Amal, R
研究了未改性TiO_2和载银TiO_2（Ag-TiO_2）光催化剂对Se（VI）的光催化还原。在甲酸存在下，TiO 2和Ag-TiO 2光催化剂均能有效还原Se（VI）。反应通过Se（VI）离子还原成元素硒Se，然后还原成硒化氢气体（H2Se）来进行。当使用未改性的TiO 2光催化剂时，Se（VI）还原形成的Se在溶液中Se（VI）耗尽后进一步还原为H2Se形式的Se 2-。在Ag-TiO 2光催化剂的存在下，硒（VI）的还原同时产生硒化氢气体。结果表明，Se（VI）的最大还原速率出现在pH3.5和0.5at.% Ag负载，而最大硒化氢气体产生发生在pH 3.5和2.0原子% Ag负载。Se（VI）同时还原成硒化氢气体可归因于由于Ag颗粒的光生电子的介导而引起的有效电荷分离。提出了紫外光照射过程中TiO 2-Ag-Se电子相互作用的机理。(C)2003 Elsevier Science B. V.保留所有权利。
The photocatalytic reduction of selenate Se(VI) ions was studied using unmodified TiO2 and Ag-loaded TiO2 (Ag- TiO2) photocatalysts. In the presence of formic acid, both the TiO2 and Ag-TiO2 photocatalysts were effective in reducing Se(VI). The reaction proceeded through the reduction of Se(VI) ions to elemental selenium Se and then to hydrogen selenide gas (H2Se). When unmodified TiO2 photocatalyst was used, the Se formed from the reduction of Se(VI) was further reduced to Se2- in the form of H2Se upon the exhaustion of Se(VI) in solution. In the presence of the Ag-TiO2 photocatalysts, hydrogen selenide gas was generated simultaneously with the reduction of Se(VI). It, vas found that the maximum Se(VI) reduction rate occurred at pH 3.5 and at a 0.5 at.% Ag loading while the maximum hydrogen selenide gas generation occurred at pH 3.5 and at 2.0 at.% Ag loading. The simultaneous reduction of Se(VI) to hydrogen selenide gas can be attributed to efficient charge separation due to the mediation of photogenerated electrons by the Ag particles. A mechanism is proposed in terms of the TiO2-Ag-Se electronic interaction during UV irradiation. (C) 2003 Elsevier Science B.V. All rights reserved.