| 초록 |
The environmental impact of high concentrations of CO2 in the atmosphere has been of acute concern to the global community (1-3). One of the ways to mitigate this problem is to convert CO2, at the generation point, to valuable industrial feed stocks such as lower olefins and liquid hydrocarbons (1-5). Iron based catalysts have shown great promise in reverse water gas shift (RWGS) reaction as well as F-T synthesis, which are the two major steps involved in the hydrogenation of CO2 (2,3). Potassium was found to be an effective promoter for iron based catalysts in the F-T synthesis (2,3). With the addition of potassium to an iron catalyst, production of light olefins and long-chain hydrocarbons is expected to be enhanced markedly. On the other hand, several authors (4,5) emphasized the importance of support in iron catalysts for F-T synthesis, as it is expected to influence the iron particle size, reducibility, degree of interaction with the support and the chemical form of species present at the surface of the catalyst. Cagnoli et al (5) reported that basic supports like MgO gives improved selectivity to light olefins compared to Fe catalysts supported on typical materials like SiO2 and Al2O3 (4,5). However, use of MgO alone has support can lead to poor dispersion. In the present study, we have used Al2O3-MgO mixed oxides as supports for potassium promoted iron catalysts in CO2 hydrogenation. These catalysts have been characterized by XRD, BET surface area, TPR, TPDC and CO2 chemisorption techniques. An attempt has also been made to correlate the results with hydrocarbon distribution in CO2 hydrogenation.
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