CO2 capture and methanation over iron and cobalt-containing catalysts operated in a domestic microwave oven

Abstract

SiC and Fe3O4 were used as microwave (MW) susceptors in a novel type of domestic MW oven featuring the so-called “Inverter” technology used for CO2 trapping and methanation. A catalyst based on cobalt was added and the conversion of CO2 was studied both in continuous mode (co-feeding H2 and CO2) and pulsed mode (sequential CO2 trapping and desorption/hydrogenation). CO2 conversion up to 80 % could be achieved over the physical mixture of SiC, Fe3O4 and Co/Al2O3, although high selectivities to CO were observed. The periodic glow of the susceptors and the corresponding oscillation of the catalytic activity at powers lower than 440 W revealed that MW power delivery was actually pulsed, unlike the manufacturer claim. Higher output power enabled both higher CO2 conversion rate and selectivity to CH4. The catalytic performances were improved by operating in CO2 trapping/methanation mode as compared to a continuous flow mode.