液相非熱電漿技術製備奈米級含氮二氧化鈦於可見光下降解有機污染物之研究

Degradation of organic contaminants using liquid-phase non-thermal plasma prepared N-doped TiO2 under visible light irradiation

曾偉綸(Wei-Lun Tseng)

指導教授 ： 陳孝行

國立臺北科技大學/工程學院/環境工程與管理研究所/碩士(2009年)

https://doi.org/10.6841/NTUT.2009.00120

摘要

本研究以電暈放電之型態，研發自製一套新穎、備製時間短、低耗能且常壓常溫之液相非熱電漿系統，藉由予瞬間產生一強烈之電場與伴隨之UV光，製備出含氮二氧化鈦 (TiOxNy) 光觸媒。本研究應用商業級之Degussa P-25 (DP-25) 和氯化銨粉末混合於去離子水，藉由高壓放電，將TiO2中之O原子由Ti中趕出，順利的將NH4Cl中的N原子與TiO2中的O原子進行置換，縮短二氧化鈦之能隙，改變二氧化鈦光吸收特性以利可見光使用，並有效的增加光催化效益。
本研究所製備出含氮二氧化鈦之最佳控制參數為商業級Degussa P-25 (DP-25)與氯化銨之比例為 1：6 ，在常溫常壓條件下，電漿製備時間為40分鐘 。透過化學分析影像能譜儀 (ESCA) 表面元素分析、能量散佈光譜儀 (EDS) 及紫外光/可見光吸收光譜儀 (UV/Visible) 可得知：電漿製備時間為40分鐘時，已成功將N原子與TiO2中的O原子進行置換，產生O-Ti-N 鍵結(含氮量為 0.43 at.%)，藉由 UV/Visible 分析得知含氮二氧化鈦之吸收光譜皆位移至可見光區域 (＞400 nm)，能隙從 Degussa P-25的 3.2 eV降低至 TiOxNy的 2.82 eV，而從X 光繞射儀 (XRD) 分析中發現，高壓放電過程 (14.1 W、40 min) 並不改變二氧化鈦之晶相變化，依舊維持原本anatase晶相之型態，爾後經由可見光下(光波長為419 nm)進行偶氮染料（Acid Orange 7）降解，約在12小時後降解效率即能達到85％，其最佳反應速率約為Degussa P-25之3.4倍。

關鍵字

液相非熱電漿 ； 含氮二氧化鈦 ； 光催化活性 ； 可見光 ； 光觸媒

並列摘要

We have developed a simple, economical procedure for preparing nano-crystalline nitrogen-doped TiO2 by adopting a corona-type non-thermal plasma technology. The suspended mixture of Degussa P-25 TiO2 in NH4Cl solution was irradiated under the high-voltage discharge system to dope nitrogen from NH4+ into TiO2 nano particles. And the N-doped TiO2 truly improve the visible light utilization rate and decompose pollutants in the visible light range.
The obtained N-doped TiO2 photocatalysts were characterized with UV-Vis spectrophotometer, XRD, ESCA, SEM and BET surface area, respectively. The UV-Vis spectrum of N-doped TiO2 showed that the absorption band was shifted to 439 nm and the band gap was reduced to 2.82 eV. From the ESCA spectra showed that the presence of N-doping in the TiO2 particles is substantiated by N 1s spectra. The structure analysis of XRD spectra showed that the peak positions and the crystal structure were scarcely changed by plasma-treating at 14.1 W for 40 min, which still remain anatase type. The photocatalytic activity of N-doped TiO2 was evaluated by conventional de-colorization method using Acid Orange 7 and visible-light (wavelength is 419 nm). Eighty-five percent of Acid Orange 7 was degraded under visible light irradiation for 12 hours.

並列關鍵字

Liquid phase non-thermal plasma ； N-doped TiO2 ； Visible light irradiation ； Acid Orange 7 ； Photocatalyst.

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