Understanding the effects of manganese on reduction, reaction and dynamic behavior on catalytic activity of nickel-manganese spinel CO2 meth

Nickel-based spinel are stable, active and selective catalysts for the methanation of CO2, but their stability makes them difficult to activate. By adjusting the composition of such spinels, the reducibility at low temperatures is significantly increased. The methanation of CO2 using nickel spinels has not yet been studied under operando conditions to correlate the structural changes to the catalytic properties. Here, the influence of manganese on the reduction process and its role in the reaction will be investigated. First, investigate in EXAFS/XANES information on the evolution of the oxidation states and the local coordination environment of the metals (Ni and Mn) during reduction and catalysis. We couple it with XRD, to correlate these changes with accompanying changes in the long-range order of the material. These information will increase the understanding of properties required for highly active spinel catalysts in CO2 methanation and thus contributes to better catalysts.