The catalytic performance of different promoted iron catalysts on combined supports Al2O3 for carbon dioxide hydrogenation

Abstract

Global warming, fossil fuel depletion and fuel price increases have motivated scientists to search for methods for the storage and reduction of the amount of greenhouse gases, especially CO2. The hydrogenation process has been introduced as an emerging method of CO2 capture and convertion into value-added products. In this study, new types of catalysts are introduced for CO2 hydrogenation and are compared based on catalytic activity and product selectivity. The physical properties of the samples are specified using BET. Iron catalysts supported on γ-Al2O3 with different metal promoters (X = Ni, K, Mn, Cu) are prepared through the impregnation method. Moreover, Fe–Ni catalysts supported on HZSM5-Al2O3 and Ce–Al2O3 are synthesized. Samples are reduced by pure H2 and involved in hydrogenation reaction in a fixed bed reactor (H2/CO2 = 3, total pressure = 10 MPa, temperature = 523 K, GHSV = 2000, 1250 nml/min). All catalysts provide high conversion in hydrogenation reactions and the results illustrate that the selectivity of light hydrocarbons is higher than that of methane and CO. It is found that Ni has a promoting effect on the conversion fluctuations throughout the reaction with 66.13% conversion. Using combined supported catalysts leads to enhancing catalytic performance. When Fe–Ni/γ–Al2O3—HZSM5 is utilized, CO2 conversion is 81.66% and the stability of the Fe–Ni catalyst supported on Al2O3 and Ce–Al2O3 furthey improves.