- 作者: 何瑞文 ; 陳韋廷 ; 吳岱恩
- 作者服務機構: 成功大學化學系
- 中文摘要: A series of Ti-promoted (6wt%) Co/SiO/sub 2/ catalysts with titania content of 0 to 10wt% were sequentially prepared by incipient wetness impregnation and characterized with X-ray diffraction, thermogravimetric analysis, chemisorption, temperature- programmed desorption and infrared spectroscopy. The influences of Ti addition and reduction temperature (400-700.degree.C) on the adsorptive behavior and the catalytic properties for CO hydrogenation were investigated. The presence of Ti decreases the adsorption capacity of the cobalt surface for H/sub 2/, but enhances activity per gram cobalt. In addition, the turnover frequency increases 2-4 times upon Ti addition at reduction temperatures of 400-700.degree.C. The promotion in activity is accompanied by an enhanced selectivity for higher hydrocarbons and olefins. These modifications can be rationalized by the creation of active sites for CO dissociation. The desorption of CO/sub 2/ at 100.degree.C during temperature-programmed desorption of CO indicates the formation of active sites for CO disproportionation. Infrared spectroscopy indicates an increase in the relative absorbance of 2,060-2,075cm/sup -1/ bands upon Ti addition, which are attributed to CO adsorbed on the defect sites of the cobalt surface. Therefore, the promotion effect of Ti may be directly related to the formation of defect sites on the cobalt surface induced by the decorated titania moieties.
- 英文摘要: --
- 中文關鍵字: Titania; Hydrogenation; Carbon Monoxide Chemisorption; Temperature Programmed Desorption; Infrared Spectroscopy
- 英文關鍵字: 二氧化鈦;氫化;一氧化碳化學吸附;程溫脫附;紅外線光譜