製備條件對Au/TiO2與Cu/C觸媒於NO+CO反應的影響

李彥潔

指導教授 ： 林昇佃

元智大學/工程學院/化學工程與材料科學學系/碩士(2001年)

摘要

本研究探討NO還原反應用之IB觸媒，概分為兩個部份，在金觸媒方面主要在探討HTR(High-Temperature Reduction)前處理步驟對Au/TiO2觸媒的影響，在銅觸媒方面則是在探討添加成分Ti在Cu/C中與Cu所產生的交互作用。
在Au/TiO2的HTR前處理步驟探討中，發現在HTR步驟中通入H2的時機會影響觸媒的反應特性，結果顯示在低溫通入H2進行HTR所得觸媒的反應活性較好，從DRIFTS (Diffuse-Reflectance Infrared Fourier-Transformed Spectroscopy)中也可看出經不同HTR處理步驟對所得觸媒的CO與NO的吸附特性有明顯的不同，然而XAS (X-ray Absorption Spectroscopy)卻無法分辨不同的HTR步驟對於Au/TiO2觸媒結構的改變。
在Cu/C觸媒中，實驗發現在低溫(< 523K)的活性是以Carbon表面的活性為主，在高溫時才有銅的活性貢獻，而含浸不同比例的Ti於Cu/C觸媒之中，並不會影響Cu/C在高溫的活性，但卻會使低溫範圍的活性下降，顯示Ti與C之間有交互作用，因而造成觸媒在低溫活性下降。從XAS的分析中可發現，Ti會促使Cu穩定在CuO的結構。

關鍵字

Au/TiO2 ； Cu/C ； 觸媒 ； NO ； CO

並列摘要

This study focused on supported Group IB catalysts for the NO+CO reaction. Two catalysts are of particular interest, namely, Au/TiO2 and Cu/C. The Au/TiO2 catalyst was prepared by impregnation and the effect of HTR (high-temperature reduction) pretreatment procedures was examined. The timing (temperature) of H2 addition during HTR significantly affected the catalytic activity. A more active catalyst was obtained when H2 was introduced at lower temperatures during HTR. DRIFTS (Diffuse Reflectance Infrared Fourier-Transformed Spectroscopy) showed that CO and NO adsorption were also affected by the timing (temperature) of H2 addition during HTR. However, the Au LIII-edge X-ray Absorption Spectroscopy (XAS) showed no significant morphological difference among Au/TiO2 pretreated with different HTR procedures.
For Cu/C catalysts prepared by impregnation method, this study examined the effect of Ti incorporation on the catalytic activity. It was found that the activity could be roughly divided to that from carbon surface at <523K and that from copper surface at higher temperatures. The addition of Ti resulted in a decrease in lower-temperature activity; whereas, no significant effect was observed with higher-temperature activity. The Cu K-edge XAS results showed that the incorporation of Ti stabilized the CuO phase in Cu/C catalysts instead of the Cu phase when without Ti.

並列關鍵字

HASH(0xdb175f0)

參考文獻

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