Preferential chemical vapor deposition of ruthenium on cobalt with highly enhanced activity and selectivity for Fischer-Tropsch synthesis

详细信息    查看全文

• 作者：Mohammad Javad Parnian ; Abbas Ali Khodadadi ; Ali Taheri Najafabadi ; Yadollah Mortazavi
• 关键词：Chemical vapor deposition ; Ruthenium ; Cobalt ; Fischer&ndash ; Tropsch synthesis
• 刊名：Applied Catalysis A: General
• 出版年：30 January, 2014
• 年：2014
• 卷：470
• 期：Complete
• 页码：221-231
• 全文大小：5525 K

文摘

Various amount of ruthenium was preferentially deposited on cobalt of Co/纬-Al₂O₃ by chemical vapor deposition (CVD) of ruthenocene and compared with a CoRu/纬-Al₂O₃ catalyst prepared by the usual impregnation method for Fischer-Tropsch synthesis (FTS). The Co/纬-Al₂O₃ was prepared by wet impregnation of cobalt nitrate aqueous solution, and then dried and calcined at 400 掳C for 4 h. Ruthenocene was sublimated, carried by argon, and then mixed with H₂ and passed over 纬-Al₂O₃ or calcined Co₃O₄/纬-Al₂O₃ catalyst at various temperatures. The effluent gasses were passed through a gas cell of FTIR to determine the ruthenocene thermo-chemical decomposition products. In a temperature range (window) of 150-200 掳C the ruthenocene decomposes on Co₃O₄/纬-Al₂O₃ but not on 纬-Al₂O₃. The catalysts were characterized by TPR, EDX, TEM, XRD and BET. The FTS activity and selectivity of the Ru-Co/纬-Al₂O₃ catalysts were investigated in a fixed bed microreactor. The preferential CVD of 0.3 wt% ruthenium onto 15.0 wt% Co/纬-Al₂O₃ (CoRu5-180) catalyst shifted both cobalt TPR peaks by about 120 掳C to lower temperatures, showed about 2.8 times higher conversion, 30% more C₅₊ selectivity, and 30% less selectivity of methane. The CoRu5-180 catalyst showed about 81% higher CO conversion and 12% higher selectivity to C₅₊ than the same catalyst composition prepared by the used impregnation of ruthenium chloride onto the 15.0 wt% Co/纬-Al₂O₃.