複合鍍TiO2-Ni光觸媒之製造與特性分析

Abstract

光催化觸媒是近年來分解有機污染物、水質的淨化和工業廢水最有潛力的方法，由於觸媒本身不會因化學反應產生變化或破壞本體結構，且在奈米尺寸顆粒催化劑上發生的光電化學反應生成之OH-、O2-等高活性物質，可輕易將空氣中的有機化合物、硫醇、NOx及臭氧等轉換成二氧化碳和水，使得奈米光觸媒具有抑菌、殺菌、無毒性及自淨性等特性，成為理想環保產品，故開發此相關製程為一值得研發之議題。 本實驗係以電鍍法製作光觸媒TiO2-Ni複合鍍層，在不同的電鍍參數（電流密度及pH值）下，探討複合鍍層表面形貌與成分分析等；並對TiO2粉末進行高溫煅燒以得到不同熱處理溫度下的粉體型態，之後以大腸桿菌作殺菌測試，藉此評估TiO2之光催化效能。 實驗結果顯示pH = 4.5及電流密度為8ASD下，可得到最佳之TiO2-Ni複合鍍層，此條件下之粉體沉積量最多且分散效果最均勻。在殺菌方面，於僅煅燒TiO2的製程中，以600℃具有最大之抑菌成效；而TiO2連同Ni基材一起經由煅燒處理後，則以800℃具有最明顯之抑菌生長能力；整體而言，anatase晶型之光催化活性較rutile晶型高。另外在光電化學特性方面，TiO2-Ni鍍層經由紫外光照射後，其電荷傳輸阻抗值均較未經紫外光照射者低。

The photocatalyst has been the most potential method for degradation of organic contamination, purification of water and industrial sewage in recent years. The catalyst itself will not undergo changes and its structure will not be damaged as a result of the chemical reaction. In addition, high active species like OH-, O2- etc. will be produced during the photoelectrochemical reaction occurred on the nano-sized catalyst; these species can readily transform organic compounds, mercaptan, NOx and ozone in the atmosphere into CO2 and H2O. The properties of nano-sized TiO2, such as anti-bacterial, non-toxic and self-cleaning, make it an ideal environmental protection product. Therefore, the relative fabrication and characterization process is worth developing. For this study, TiO2-Ni composite coatings were electroplated with various electroplating parameters like current density and pH value. The morphology and composition of the deposited surface layer were studied in detail. Then calcining TiO2 powder at high temperature was performed to achieve the different structure as well as morphology. Finally, as-formed TiO2-Ni was employed to disinfect the colon bacillus for evaluating its catalyzing efficiency. Results indicated that the best TiO2-Ni composite coatings could be obtained at pH 4.5 and current density at 8ASD. Under this condition, highest amount of deposited powders with uniformly distribution was achieved. In the sterilization, it had the best anti-bacterial efficiency at 600℃ among the process of only calcining TiO2; howener, calcining TiO2 with Ni substrate together was at 800℃. Approximately, TiO2 with anatase phase has better photoinducing activity than that of rutile phase after calcining. In photo-chemical analysis, TiO2-Ni coatings with UV radiation had lower charge transmission resistance than that without UV radiation.