Alumina and silica supported Ce–Fe–O systems obtained by the solution combustion method and their performance in CO$_2$ hydrogenation to syngas

This study presents Ce–Fe–O systems supported on $\gamma$-Al$_2$O$_3$ or SiO$_2$ to enhance the reactivity of an oxygen-deficient CeFeO$_3$ perovskite phase, which are promising catalysts for the production of fuels and chemicals from CO$_2$ as feedstock. The synthesis was carried out by the glycine-nitrate solution combustion method at various fuel-to-oxidizer ratios, and with or without the addition of ammonium nitrate. The obtained composites were characterized by XRD, SEM, EDX, N$_2$-physisorption, H$_2$-TPR, and CO$_2$-TPD to study the relationship of physicochemical properties with catalytic CO$_2$ hydrogenation (rWGS) activity. $\gamma$-Al$_2$O$_3$ was found to be a more suitable support than SiO$_2$ due to its ability to form a higher content of the perovskite phase, significantly reduce the size of CeFeO$_3$ crystallites, and increase oxygen defectiveness and CO$_2$ adsorption capacity. Combustion in the presence of silica results in the binding of most of cerium into a silicate phase, which is inactive for rWGS.