Co3O4-CeO2 for enhanced syngas by low-temperature methane conversion with CO2 utilization via a catalytic chemical looping process

Abstract

Fabricating effective transition metal-based oxygen carriers (OCs) in a low-temperature methane chemical looping conversion is of considerable importance but remains challenging. Herein, a series of Co3O4-CeO2 metal oxides were synthesized and used as OCs in a low-temperature methane conversion with CO2 utilization via chemical looping systems. Co3O4/CeO2–3 (Co/Ce ratios =7/3) showed the better performance with CH4 conversion above 70%, the highest hydrogen yield and CH4 conversion up to 55.73 mmol/g and 94.09% at 700 °C. The enhancement on the performance of Co3O4/CeO2–3 for hydrogen production is attributed to the interaction between Co3O4 and CeO2 particles at the interfaces, which could cause charge redistribution. Compared to pristine Co3O4, this structure endows Co3O4-CeO2 with higher CH4 conversion performance. Moreover, the resulting Co0 in the reduced OCs is beneficial for catalytic methane decomposition toward C and H2, followed by C gasification into CO during CO2 atmosphere with CO2 conversion as high as 81%. In the proposed chemical looping processes, catalytic methane decomposition step is active for hydrogen production, coupling with CO2 conversion toward CO to adjust the H2/CO ratio of syngas.