具可見光應答之Cr/TiO2奈米光觸媒

Visible-light Response Cr-doped TiO2 Nano Photocatalysts

潘建呈(Chien-Cheng Pan) ； 吳紀聖(Jeffrey C.-S. Wu)

《界面科學會誌》 26卷4期 (2004/12) Pp. 175-182

https://doi.org/10.30020/JCCIS.200412.0001

摘要

為了更有效率的利用太陽光或是室內光源，本研究致力於研發具有可見光應答催化活性之二氧化鈦光觸媒。利用改良式溶膠凝膠法合成摻雜鉻元素之二氧化鈦。同時透過X光繞射儀（X-ray diffractometer, XRD）、紫外光－可見光吸收光譜儀（Ultra-violet-visible spectrophotometer, UV-VIS）、X射線光電子譜儀（X-ray photoelectron spectroscopy, XPS）與X光吸收光譜術（X-ray absorption spectroscopy, XAS）分析所改質二氧化鈦之表面與整體結構。相較未經改質之本質二氧化鈦以及商用觸媒P25，摻質後的二氧化鈦成功的具備吸收波長小於550nm之可見光的能力，並且能夠有效的催化亞甲基藍染料水溶液的還原脫色反應、以及異丙醇水溶液的氧化分解反應。在二氧化鈦中摻入鉻元素的改質製程，使價態與傳導帶間形成其他的獨立能階，進而縮小能隙、降低電子電洞對分離所需激發光子之能量，始能達到改質可見光應答目的。摻雜鉻元素之量具有一最適值，過量摻雜之鉻元素會因局部聚集而扭曲本質結構，造成二氧化鈦原本具有之良好光量子效益降低。

關鍵字

二氧化鈦 ； 光觸媒 ； 可見光

並列摘要

To use solar or interior light efficiently, we developed a titania photocatalyst with high reactivity under visible light. Titania powders were prepared and doped with chromium ions via modified sol-gel method. The photocatalysts were characterized by X-ray diffractometer (XRD), ultra violet-visible spectrophotometer (UV-VIS), X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS). Doped titania revealed an improvement over pure titania and Degussa P25 photocatalyst in visible light (wavelength＜550nm) absorption and photocatalytic activity in photodegradations of methylene blue and isopropyl alcohol. Incorporated chromium in titania was responsible for the visible-light photocatalytic activity. An isolated band was formed between the valence and conduction bands, narrowing the band-gap and lowering the photon energy required to excite the electrons. An optimum amount of doped chromium was required. Excess doped chromium locally aggregated in the lattice distorted the original structure and consequently deteriorated the intrinsic photocatalytic activity of titania.

並列關鍵字

Titania ； Photocatalyst ； Visible-light