Photo-Catalysis of Refractory Organics with Nano-Semiconductors.

本計畫之研究目的針對光催化之 TiO2 觸媒進行性質上的改良。嘗試利用各 種半導體材料如：硒化鎘（CdSe）、二氧 化錫（SnO2）及三氧化鎢（WO3）結合二 氧化鈦（TiO2）成為複合態觸媒，應用於 光催化降解4-氯酚（4-cholorophenol）的 研究，以尋求更高效率的光催化觸媒進行 水中有機物降解。 在光催化降解4-氯酚的方面，照光波 長365 nm 下，複合態觸媒去除4-氯酚的 效果較單獨態提高約9%，整體而言，利 用CdSe 結合TiO2 較無法達到理想的去除 效果，結合SnO2 的複合觸媒無法提升光 催化分解能力。 WO3/TiO2 的臨界激發波長為475 nm，利用可見光波長範圍的435 nm 進 行，在pH=4 條件下，WO3/TiO2 於180 分 鐘內4-氯酚的去除率可達75%，TOC 的去 除率在180 分鐘內有50%。由此實驗結 果，增加了直接利用太陽光進行光催化程 序的可行性。The photocatalytic process using TiO2 and coupled semiconductor in the photodegradation reaction of 4-CP was investigated. Nanosized titanium dioxide power was synthesized via various procedure and modified the via coupled photocatalysts. The microstructural and chemical properties of titanium dioxide and coupled cadium selenide/titanium dioxide, stannic dioxide/titanium dioxide, tungsten trioxide/titanium dioxide were also examined. In the results of photocatalysis, higher photodegradation efficiency of 4-CP was observed at higher pH values. In general, the coupled cadium selenide/titanium dioxide and stannic dioxide/titanium dioxide were unable to perform satisfied efficiency on 4-CP destruction. Instead, the coupled tungsten trioxide/titanium dioxide irritated at 435 nm visible light was able to achieve a 75% photo-catalytical removal of 4-CP at pH 4 condition in a 180 min reaction period. The most significant result of this experiment is that the reaction can be initiated under visible light situation without using UV light