• 作者： Lee, Min-Dar; Chang, Chau-Shang; Lee, Jhy-Fu
• 中文摘要： 利用梅思堡光譜, 升溫規劃脫碳及動力學測試, 探討鐵及鉀/鐵觸媒在二氧化碳氫化反應中之催化行為與結構變化。在常壓下, 鐵中添加鉀對於CO/sub 2/之總轉化率影響不大, 但可顯著抑制烴類之生成, 而CO為主要之產物。反之, 壓力為1MPa時, 添加鉀可促進 CO/sub 2/之轉化率, 並提高低碳烯烴與 C/sub 5+/烴之選擇率。金屬鐵在反應過程中同時被碳化及氧化, 鉀之存在有利於總體碳化物之生成, 而反應壓力之升高則有助長 Fe/sub 3/O/sub 4/之效應。鉀/鐵觸媒上所生積碳比鐵觸媒更不易脫離。
• 英文摘要： Studies on the phase change and catalytic behavior of iron catalysts during CO/sub 2/ hydrogenation were conducted using Mossbauer spectroscopy, temperature-programmed decarburization, and kinetic measurement. At atmospheric reaction pressure, the addition of potassium to iron catalyst significantly depressed the yield of hydrocarbons and hence CO was the main product. Potassium had a smaller effect on the overall conversion of CO/sub 2/. In contrast, both CO/sub 2/ conversion and hydrocarbon yield on the promoted catalyst were higher than on the unpromoted catalyst at 1.0MPa. The selectivities toward light olefins and C/sub 5+/ hydrocarbons were increased due to the addition of potassium. Metallic iron catalyst was carburized as well as oxidized during reaction. It was found that the presence of a potassium promoter favored the bulk carbide formation while the formation of Fe/sub 3/O/sub 4/ was preferable at higher reaction pressures. The temperature-programmed decarburization studies also indicated the enhancement of carburization ability of iron by potassium. The carbon deposits during reaction were more difficult to evolve from a promoted catalyst than from an unpromoted catalyst.
• 中文關鍵字： 梅斯堡光譜; 鐵催化劑; 二氧化碳; 氫化; 相變化
• 英文關鍵字： Iron Catalyst; Carbon Dioxide; Hydrogenation; Phase Change; Mossbauer Spectroscopy