Study on the carbon dioxide hydrogenation to iso-alkanes over Fe-Zn-M/zeolite composite catalysts

Synthesis of iso-alkanes from carbon dioxide hydrogenation was investigated over Fe-Zn-M/Zeolite composite catalysts. The effects of different promoter metals (M=Cr, Mn, Zr, Al, La) and zeolites on the performance of carbon dioxide hydrogenation were studied. The structure and the acidity of zeolites were investigated by IR, NH3-TPD and Py-IR. It was found that Zr had a better promotional effect than other additive metal components for the iron-based catalyst. The catalyst had different catalytic performances with different zeolites and the distribution of hydrocarbon products was influenced by the acidity of the zeolite. The HY zeolite was the most effective one for iso-alkane synthesis due to its medium-strength and strong acid sites, which could be observed through temperature-programmed desorption of ammonia (NH3-TPD). (C) 2004 Elsevier B.V. All rights reserved.