利用Au/TiO2在紫外及可見光下降解苯酚水溶液的反應之研究

Photocatalytic Degradation of Phenol Solution in the Presence of Au/TiO2 Catalyst under the Irradiation of UV and Visible Light

沈運祥(Yun-Hsiang Shen)

指導教授 ： 吳乃立

國立臺灣大學/工學院/化學工程學研究所/碩士(2011年)

https://doi.org/10.6342/NTU.2011.00477

摘要

本研究的目的是想探討利用Au/TiO2對於工業廢水內常見的有機物苯酚進行光催化降解反應，並且觀察中間產物的濃度分佈與選擇性的變化，以及侷域性表面電漿共振 (LSPR) 效應是否可顯著地提升反應速率。

　　本研究分為三大部分。第一部分是用300 nm的紫外光源對苯酚的兩種不同的初始濃度 (250 ppm or 150 ppm) 分別進行光催化降解反應，結果發現苯酚的反應速率常數幾乎不受初始濃度影響。第二部分則是探討溫度效應對於P25與2.0 wt% Au/P25催化活性的影響，我們發現當溫度由32℃上升到38℃時，苯酚的反應速率常數不升反降。之後將反應溫度提高到55℃時，苯酚的反應速率常數也只有略微提升，推測原因可能與吸附步驟是速率決定步驟有關。第三部分是將300 nm紫外光與575 nm可見光燈管同時打開，觀察Au/TiO2的LSPR效應是否會對反應速率造成顯著的影響。結果發現苯酚的反應速率常數有略為提升，中間產物的部分雖然速率常數提升有限，經過與只照可見光的對照組比較，我們覺得LSPR效應應該有助於提升反應速率。

關鍵字

二氧化鈦 ； Au/TiO2 ； 苯酚 ； 光催化降解反應 ； 侷域性表面電漿共振

並列摘要

The purpose of this research is to apply Au/TiO2 for the photocatalytic degradation reaction of phenol, a commonly found organic compound in industrial wastewater, and to observe the concentration profiles as well as the selectivity of the intermediates. In addition, we want to investigate whether Localized Surface Plasmon Resonance (LSPR) effect can enhance the reaction rate.

This research is divided into three parts. First, we illuminated the phenol solution with 300 nm UV light only. The initial concentration of phenol solution is 250 ppm and 150 ppm, respectively. We found that the reaction rate constant of phenol was nearly independent of the initial concentration. The second part is to explore the temperature effect on the kinetics when using P25 and 2.0 wt% Au/P25 as the catalyst, individually. We observed that when the reaction temperature increased from 32℃ to 38℃, the reaction rate constant of phenol dropped. Even when we elevated the reaction temperature to 55℃, the reaction rate constant of phenol only slightly increased. We suppose that it is because the adsorption step rather than the surface reaction step is the rate-determining step.

The third part is to illuminate the phenol solution with 300 nm UV and 575 nm visible light at the same time. The reaction rate constant of phenol became a little larger when applying dual light sources. As for the mono-hydroxylated intermediates, although the increase in the reaction rate constant was not obvious, when compared with the data obtained by illuminating the solution with UV light only, we believe that LSPR must promote the overall reaction rate of the photocatalytic degradation reaction of phenol.

並列關鍵字

Titanium dioxide ； Au/TiO2 ； Phenol ； Photocatalytic degradation reaction ； Localized Surface Plasmon Resonance (LSPR)

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