比較乙醯丙酮螯合鈦等不同前驅物利用水熱法製備奈米二氧化鈦及性質分析

半導體光催化法是目前受到相當重視的有機汙染處理新技術。許多學者在光催化有機廢水，大氣中的有機污染物方面進行大量的研究工作，發現以二氧化鈦為首的光催化劑對於廢水毒性物質以及空氣中殘餘有機物方面具有相當的潛力。二氧化鈦的光催化特性和其本身的顆粒大小及結晶的相態都有密切的關連，較小觸媒顆粒具較高比表面積導致較高的催化效率，因此製備奈米級的二氧化鈦粉體並探討製備條件與觸媒大小及結晶性的相互關係是目前發展的一重要課題。傳統二氧化鈦合成是利用含鈦的金屬烷氧化物或含鈦的金屬鹽類為前驅體，加以水解及熱處理。而部分報告指出加入螯合劑可以控制二氧化鈦的顆粒大小、均勻性及結晶性。本研究嘗試利用新的二氧化鈦前驅物：titanium isopropoxide (1) 以及titanium bis(acetylacetonate) diisopropoxide (2)，使用水熱法及高溫煅燒製備出結構穩定且粒子均勻的奈米二氧化鈦，並做比較。水熱法可避免煅燒過程中，二氧化鈦表面的OH基因高溫脫水而使得二氧化鈦粒徑增大，比表面積變小，影響其光催化效果。將所得光觸媒粉末分別利用X光繞射儀(XRD)分析結晶相成份、結晶強度及不同晶相所佔比例；穿透式電子顯微鏡(TEM)測量粒徑大小及分佈；化學分析能譜儀(ESCA)分析表面成分及化學組態；以氮氣吸附脫附儀量(BET)測粉末的比表面積與孔徑大小分布。在反應條件設定方面，利用含鈦的金屬烷氧化物或乙醯丙酮螯合鈦做為前驅物、反應時間、煅燒溫度等進行變化，以便控制二氧化鈦粒子的成長。初步結果顯示，兩者皆成功製得奈米二氧化鈦。水熱反應後，經低溫150 oC烘乾時，其相態均為銳鈦礦相(Anatase phase)，而煅燒溫度在800 oC以上時，發現相態由銳鈦礦相(Anatase phase)些相轉變成金紅石相(Rutile phase)。我們以亞甲基藍(Methylene blue)的光催化裂解反應，探討水熱處理後所得二氧化鈦的光催化活性。本研究以此為開端提供鈦螯合方式的前驅物進而製備更不同的結晶奈米二氧化鈦和形態的研究空間。

關鍵字

二氧化鈦；螯合鈦前驅體；水熱法；銳鈦礦；金紅石

並列摘要

The semiconductor photochemical catalysis is the new technology for organic pollution that is paid much attention to at present. Many scholars carry on a large amount of research work in the photochemical catalysis organic waste water and atmospheric organic pollutant aspect , discovered titanium dioxide has suitable potentiality to the remaining organic matter regarding in the waste water toxic material as well as the air.The photocatalytic application of TiO2 nanoparticles shows strong correlation with its particle size and crystal property. Therefore, the systematic investigation on the TiO2 synthesis as well as the crystal phase evolution of the TiO2 product becomes very important. In general, TiO2 synthesis used precursors for the titanium alkoxide or titanium metal salt which are hydrolyzed and thermal treatment to obtain TiO2 crystals. Some reports indicated that adding chealting agent in the process of TiO2 synthesis effects the particle size, homogeneity, and crystallize of the final products. In this work, we have designed the new type of TiO2 precursors: Titanium isopropoxide (1) and titanium bis(acetylacetonate) diisopropoxide (2) as initial compound for TiO2 synthesis that used hydrothermal method and high temperature calcination. prepared for TiO2 crystals . Hydrothermal method can avoid the titanium dioxide surface OH dehydration causes the titanium dioxide particle size increase and surface area decrease at high temperature in the calcine process, influence its photochemical catalysis result. Such prepared TiO2 samples were characterized by X-ray diffraction (XRD) for the crystal structure, by transmission electron microscopy (TEM) for dimensions and distribution, by electron spectroscopy for chemical analysis (ESCA) for chemical state and by nitrogen gas adsorption/desorption isotherm for surface area measurement. By tailing the reaction condition, such as the content of acetylacetonate in the precursor molecule, the reaction time, and the calcinations temperature, the growth of TiO2 particles can be well controlled. The preliminary results show that using both precursors, anatase TiO2 was successfully obtained at hydrothermal temperature as low as 150 ºC. TiO2 was obtained at calcinations temperature as high as 800 ºC, phase transformation from anatase to rutile. Further study for the optimized condition in preparing the TiO2 is currently under the investigation.

並列關鍵字

titanium dioxide ； Acetylacetonate Titanium Precursors ； hydrothermal method ； anatase phase ； rutile phase

參考文獻

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[26] 謝逸傑，水熱法利用四乙醯丙酮鏊合鈦為前驅物製備奈米二氧化鈦之調控研究，碩士論文，國立台北科技大學，2006

[28] 彭惠美，水熱法利用雙乙醯丙酮鏊合鈦為前驅物製備奈米二氧化鈦及性質分析，碩士論文，國立台北科技大學，2006

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比較乙醯丙酮螯合鈦等不同前驅物利用水熱法製備奈米二氧化鈦及性質分析

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