Role of the Interface in Base-Metal Ceria-Based Catalysts for Hydrogen Purification and Production Processes

The role of the interface in Cu,Ni-CeO2 catalysts used for novel hydrogen purification and production processes (preferential oxidation of CO, water-gas shift reactions, and the reforming of bio-alcohols) is analyzed with an emphasis on the description of the physico-chemical properties of the interface that have a critical influence on the catalytic properties. The direct contact between the base metal and ceria, as well as a contact mediated by alien species, are studied. Critical appraisal of the results indicates that specific base-metal and ceria interaction situations control the redox response to the gas-phase atmosphere. Together with specific base-metal structural effects, these properties seem particularly important in controlling the interaction with CO and H2O as well as with carboxy/carboxylate moieties, and therefore, are important to drive the activity, selectivity, and stability for the mentioned catalytic processes.