不同方法製備TiO2於光催化降解2,4-二氯苯氧乙酸之研究

A Comparative Study of Different Methods to Prepare TiO2 for Photocatalytic Degradation of 2,4-dichlorophenoxyacetic Acid

鄭豐文(Feng-Wen Zheng)

指導教授 ： 王榮基

大同大學/工程學院/化學工程學系所/碩士(2012年)

摘要

在不同熱處理溫度下，使用四種合成方法製備TiO2 粉末。由XRD、SEM、UV-vis確定光觸媒樣品的化學與物理性質，使用BET測量所有樣品的比表面積。
由XRD結果顯示，直接水解法在烘箱熱處理85oC，12小時製備的TiO2，有著銳鈦礦與板鈦礦晶相。板鈦礦晶相含量與表面積隨熱處理溫度上升而下降。
光觸媒的光催化活性是使用UV-vis分光光度計以檢測2,4-D濃度表示之。在熱處理85oC製備的hydrolysis-TiO2樣品比25oC、50oC、200oC、300oC、400oC及其他方法製備的樣品有著更高的光催化活性。其原因可歸咎於在銳鈦礦/板鈦礦之異相加成效應，能有效的抑制電子與電洞之間的再結合進而提升光催化降解作用。

關鍵字

二氧化鈦 ； 光催化 ； 銳鈦礦 ； 板鈦礦

並列摘要

Four synthesic methods are used to prepare titanium oxide powder at different heat treatment temperatures. The chemical and physical properties of the photocatalyst samples were determined by X-ray diffraction (XRD), Scanning electron microscopy (SEM) and UV–vis diffuse reflectance spectra (UV-vis), also the specific surface area of all samples was measured by BET method.
The XRD results show that the TiO2 prepared by direct hydrolysis method and heat treatment at 85oC for 12 hrs in an oven has anatase and brookite phases. Brookite phase content and surface area are decreased with increasing that treatment temperature.
The photocatalytic activity performance of photocatalyst was evaluated by UV-vis spectrophotometer to detect the concentration of 2,4-dichlorophenoxyacetic acid (2,4-D). Hydrolysis-TiO2 prepared at heat treatment temperature of 85oC has higher photocatalytic activity performance than 25oC, 50oC, 200oC, 300oC and 400oC, as well as the other synthesic methods prepared at low temperature heat treatment. It can be attributed to that the synergistic effect of heterojunction in anatase/brookite composite can inhibit recombination rate of electrons and holes pairs to improve photodegradation performance.

並列關鍵字

photocatalytic ； TiO2 ； anatase ； brookite

參考文獻

Boer, K.W., “Survey of Semiconductor Physics: Barriers, Junctions, Surfaces,

Carp, O., C.L. Huisman, and A. Reller, “Photoinduced Reactivity of Titanium Dioxide,” Prog. Solid State Ch., 32, 331-177(2004).

Chen, F., Y. Jiao, B. Zhao, H. Yang and J. Zhang, “Anatase Grain Loaded Brookite Nanoflower Hybrid with Superior Photocatalytic Activity for Organic Degradation,” Colloids and Surfaces A: Physicochemical and Engineering Aspects, 402, 66-71(2012).

Cushing, B.L., V.L. Kolesnichenko, and C.J. O’Connor, “Recent Advances in the Liquid-phase Syntheses of Inorganic Nanoparticles”, Chemical Reviews, 104, 893-3946 (2004).

de Amarante Jr., O.P., N.M. Brito,, T.C.R.dos Santos,, G.S. Nunes and M.L. Ribeiro, “Determination of 2,4-dichlorophenoxyacetic Acid and its Major Transformation Productin Soil Samples by Liquid Chromatographic Analysis,”. Talanta, 60, 115-121 (2003).