Investigation of CO2 methanation over highly active Ni-doped CeO2 catalysts: insights into the active nickel sites

Cost efficient and long-term stable catalysts are in great demand for the CO2 hydrogenation to methane, a key process involved in conversion of CO2 into useful chemicals and fuels. Recently we prepared Ni-doped ceria nanoparticles 3.5 times more active than conventional Ni-supported on ceria. After a detailed in-situ NAP-NEXAFS study we demonstrated the formation of tetrahedral (Td) NiO sites on the surface of ceria nanoparticles which are less reducible (in H2) than standard octahedral (Oh) NiO. However soft X-ray measurements are challenging at operando conditions (1 bar of gas) while Ce M4,5- and Ni L-edge did not give access to structural and electronic variations in a reaction-time scale. Therefore we propose here an operando hard X-rays XAFS/DRIFTS of the two aforementioned catalyst to unlock Ni-Ce synergic electronic and structural behavior coupled with the precious IR information on the formed reaction intermediates finally aiming to describe the CO2 hydrogenation mechanism.