In situ investigation of the CO2 methanation on carbon/ceria-supported Ni catalysts using modulation-excitation DRIFTS
Liliana P. L. Gonçalves, Jerrik Mielby, O.S.G.P. Soares, Juliana P. S. Sousa, Dmitri Y. Petrovykh, Oleg I. Lebedev, M. Fernando R. Pereira, Søren Kegnæs, Yury V. Kolen’ko
Abstract
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.