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藉由化學侵蝕增進混相二氧化鈦之光催化性能

Advancement of Photocatalytic Activity of Mixed-phase TiO2 by Using Chemical Etching

作者:李安哲
畢業學校:大同大學
出版單位:大同大學
核准日期:2015-09-16
類型:Electronic Thesis or Dissertation
權限:Copyright information available at source archive--ttu....

中文摘要

本研究主要探討不同結晶相混合之二氧化鈦,再以化學侵蝕方法,如硫酸、鹽酸或雙氧水-氨水加以表面改質。使用甲基橙、亞甲基藍與2,4-D水溶液作為汙染物以測量其光催化活性。使用商業化產品之純銳鈦礦與金紅石粉末在不同比例下進行混合,並與自製光催化觸媒比較其光催化活性。以XRD、SEM、UV-Vis測定光觸媒之晶體表面結構與其他特性。並使用BET測量所有樣本之比表面積。
光觸媒的光催化活性是使用UV-Vis分光光度儀來檢測汙染物水溶液濃度之變化,並與商業光觸媒Degussa P25做比較。在銳鈦礦與金紅石以8:2比例混合時之樣品比其他方法製備的樣品有著較高的光催化活性,其原因可歸於銳鈦礦與金紅石不同結晶相之間所產生的加乘效應。
相較於未經化學侵蝕處理過的光觸媒,使用濃硫酸進行化學侵蝕的樣品有最高的光催化活性,此結果可歸因於濃硫酸所侵蝕出較大的孔徑及較小的粒徑所造成。
在亞甲基藍的光催化降解中,8A2R H2SO4展現與商業產品Degussa P25幾乎相同之降解活性;但在甲基橙或2,4-D之降解上則沒有。此結果可歸因於亞甲基藍的降解機構太過複雜,導致較小粒徑與較大平均孔徑的Degussa P25無法發揮其優勢。

英文摘要

The chemical etching with mixed-phase TiO2 was used for photocatalytic degradation of methyl orange, methylene blue and 2,4-dichlorophenoxyacetic acid as pollutants under ultraviolet irradiation.
Commercial TiO2 of anatase and rutile phases were mixed in different ratio, and compared photocatalytic activity with homemade TiO2 photocatalyst. Crystalline properties of all samples were evaluated by X-ray diffraction (XRD), Scanning electron microscopy (SEM) and UV vis diffuse reflectance spectra (UV-vis), and specific surface area was measured by BET method.
The photocatalytic activity of TiO2 was measured by using UV-vis spectrophotometer to evaluate the concentration of pollutants, and compared that with commercial TiO2 photocatalyst, i.e., Degussa P25. The results showed that TiO2 with anatase and rutile ratio of 8:2 (8A2R) had the best photocatalytic activity due to the synergistic effect between anatase and rutile phases.
TiO2 after chemical etching by sulfuric acid showed better photocatalytic activity than that without chemical etching because of increasing pore diameter resulted by the chemical etching and smaller particle size.
In MB photocatalytic degradation by 8A2R H2SO4 has almost the same photocatalytic activity as Degussa P25 but not in 2,4-D or MO degradation because that small particle diameter and high average pore diameter of Degussa P25 cannot have the advantage to promote the complicated mechanism of photocatalytic degradation.


指導教授 - 王榮基

委員 - 陳泰祥

委員 - 黃富昌


 

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