Thermo‐catalytic conversion of greenhouse gases (CO 2 and CH 4 ) to CO‐rich hydrogen by CeO 2 modified calcium iron oxide supported nickel catalyst

Abstract

In this study, the thermo-catalytic conversion of two principal greenhouse gases (methane and carbon dioxide) to carbon monoxide (CO)-rich hydrogen (H2) is investigated over cerium oxide (CeO2) promoted calcium ferrite supported nickel (Ni/CaFe2O4) catalyst. The CeO2 promoted Ni/CaFe2O4 catalyst was prepared using wet-impregnation technique. To ascertain the physicochemical properties, the as-prepared catalyst was characterized using various instrument techniques. The characterization of the catalysts reveals that CeO2-Ni/CaFe2O4 possesses suitable physicochemical properties for the conversion of methane (CH4) and carbon dioxide (CO2) to CO-rich H2. The thermo-catalytic reaction revealed that the CeO2 promoted Ni/CaFe2O4 catalyst displayed a higher CH4 and CO2 conversions of 90.04% and 91.2%, respectively, at a temperature of 1073 K compared to the unpromoted catalyst. The highest H2 and CO yields of 78% and 76%, respectively, were obtained over the CeO2-Ni/CaFe2O4 at 1073 K and CH4/CO2 ratio of 1. The CeO2 promoted Ni/CaFe2O4 catalyst remained stable throughout the 30 hours time on stream (TOS) while that of the unpromoted Ni/CaFe2O4 catalyst sharply decreased after 22 hours TOS. The characterization of the used catalysts confirms the evidence of carbon depositions on the unpromoted Ni/CaFe2O4 which is solely responsible for its deactivation. Whereas, there was a slightly gasifiable carbon deposited on the CeO2 promoted Ni/CaFe2O4 catalyst which could be ascribed to the interaction effect of the CeO2 promoter on the Ni/CaFe2O4 catalyst.