Study of Ceria-based materials and their application in electrochemical and gas-phase catalysis

This thesis is focused on the preparation of nanostructured ceria catalysts with an electrochemical approach and on their use in reactions relevant to environmental issues, like CO2 electrochemical reduction and low temperature catalytic combustion, in the gas phase. Supports with totally different compositions and geometries were used for the preparation of electrocatalysts and gas-phase catalysts, but in all cases ceria was cathodically deposited via an electroprecipitation process triggered by local pH increase. To study CO2 reduction, ceria was cathodically deposited on boron-doped diamond, obtaining control of its morphology and composition, both crucial aspect in ceria catalytic applications. Promising efficiency toward formate production was demonstrated, at very low overpotential. To produce catalysts for low-temperature combustion of methanol and CO oxidation, platinum and ceria were sequentially deposited onto Fecralloy 3D foams, the support currently used in industrial structured catalysts. To extend the scope of the studies on CO2 reduction, copper oxide graphenide materials were investigated and compared to ceria. These materials were shown to effectively reduce CO2 to formate, exhibiting good stability and resistance to poisoning. Their performance matched those of the best catalysts described in the literature.