Preparation of complex photocatalysts and evaluation of the photoactivity

• Main Authors: Han-Yu Lin, 林含宇
• Other Authors: Chao-Yin Kuo
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/54928519432780235745

碩士 === 國立雲林科技大學 === 環境與安全工程系碩士班 === 93 === The purpose of this study was compared the photodegradation within TiO2/Al2O3 (as TA; 1:1 w/w), SnO2/Al2O3 (as SA; 1:1 w/w), TiO2/SnO2/Al2O3 (as TSA; 1:1:1 w/w) of complex photocatalysts, and TiO2/SnO2 (as TS; 1:1 w/w) of combined photocatalysts using sol-gel method prepared TiO2 and liquid phase deposition (LPD) method prepared SnO2 respectively. Experimental results showed when calcining temperature from 400℃ rising to 600 ℃, anatase type of titanium dioxide become completely to rutile type accompanied the lower photodegradation effect. Although 600 ℃of calcining temperature could not change crystallite type of SnO2, the appropriate calcining temperature of the photocatalysts was regarded as 400℃. As according to the photo-activity of these above developed catalysts, the ultraviolet ray of 254 nm was much better than 365 nm, as a suitable light source. Photocatalytic degradation of 4-nitrophenol (at pH 11) using singular TiO2 and singular SnO2 showed 18 % and 2 % residue respectively after 120 mins of photoreaction, and better than two kind of commercial catalysts TiO2 (Merck) and SnO2 (Arcos) as 35 % and 21 % residue. The TA of activity was not obviously in the system of complex photocatalysts, however, SA indicated well activity as only 1 % residue at pH 7. Analytic results demonstrated that the powers of TiO2 were hard to adhere on the γ-Al2O3 surface, but SnO2 easily and well, and then, adsorbs as γ-Al2O3 increased the ability of photodegradation. In addition, the experimental results showed the good degradation of 4-NP increasing the effect of mineralization. NO2- ions were found in solution when mineralization happened. The result indicated the more NO2- ions as the more complete degradation of 4-NP and displayed structure of 4-NP destroyed, then 4-NP might be degraded to CO2 and H2O.