In situ investigation of the CO2 methanation on carbon/ceria-supported Ni catalysts using modulation-excitation DRIFTS

The development of novel cost-efficient, high-performing catalysts for CO2 methanation that are active at low temperatures can be optimized through the understanding of the reaction mechanism on different materials. A series of Ni-based catalysts supported on CeO2 and carbon/CeO2 composites was investigated, showing that Ni nanoparticles supported on a carbon/CeO2 composite with a 50:50 wt ratio and on pure CeO2 have excellent low-temperature activity and achieve up to 87% CO2 conversion with full selectivity towards CH4 at 370 °C. Importantly, meaningful insights on the reaction mechanism were gathered for the different types of materials by using the emerging ME−PSD−DRIFTS technique. The study of the rate of formation/consumption of the various intermediates showed that the CO2 methanation reaction follows a combination of the CO and formate pathways in the case of Ni on pure CeO2; however, in the case of Ni on the carbon/CeO2 composite, it follows only the formate pathway. [Display omitted] •In situ ME-PSD-DRIFTS was used to gather mechanistic insights for CO2 methanation.•The analytical challenges of the dynamic reaction environment were overcome.•Different intermediate steps were observed in the two different Ni catalysts.•Carbon−CeO2 composite was successfully employed, reducing the use of CeO2 by 50%.•Newly developed catalysts demonstrated excellent XCO2 ≈ 87% and SCH4 ≈ 100% at 370 °C.