Effects of structure on the carbon dioxide methanation performance of Co-based catalysts

•Co-based catalysts were prepared and used in CO2 methanation.•Co/KIT-6 catalyst exhibits high CO2 hydrogenation activity and CH4 selectivity.•Ordered bicontinuous mesoporous structure contributes to high CH4 selectivity.

Mesoporous Co/KIT-6 and Co/meso-SiO2 catalysts were prepared via hydrogen reduction and were subsequently used in CO2 catalytic hydrogenation to produce methane. The properties of these catalysts were investigated via low-angle X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) analysis, and transmission electron microscopy (TEM). The results indicate that the synthesized Co/KIT-6 and Co/meso-SiO2 catalysts have mesoporous structures with well-dispersed Co species, as well as high CO2 catalytic hydrogenation activities. The Co/KIT-6 catalyst has a large specific surface area (368.9 m2 g−1) and a highly ordered bicontinuous mesoporous structure. This catalyst exhibits excellent CO2 catalytic hydrogenation activity and methane product selectivity, which are both higher than those of the Co/meso-SiO2 catalyst at high reaction temperatures. The CO2 conversion and methane selectivity of the Co/KIT-6 catalyst at 280 °C are 48.9% and 100%, respectively. The high dispersion of the Co species and the large specific surface area of the prepared Co-based catalysts contribute to the high catalytic activities. In addition, the highly ordered, bicontinuous, mesoporous structure of the Co/KIT-6 catalyst improves the selectivity for the methane product.

Graphical abstractCo/KIT-6 and Co/meso-SiO2 catalysts were prepared and used in CO2 methanation. The Co/KIT-6 catalyst exhibits high CO2 hydrogenation activity and CH4 selectivity. The bicontinuous ordered mesoporous structure can ensure that the produced methane molecules in the pores of the Co/KIT-6 catalyst are transplanted freely. Therefore, methane molecule can be easily desorbed from the Co/KIT-6 catalyst to the gas phase to achieve high methane selectivity.Figure optionsDownload full-size imageDownload as PowerPoint slide