In recent years, mixed-metal oxides which contain ceria are receiving a lot of attention due to their applications in catalysis, materials science, photochemistry and the control of environmental pollution. CeOx-TiO2 has shown to be an excellent substrate for the dispersion of metals used in the oxidation of CO, the water-gas shift reaction, the hydrogenation of CO2 to alcohols, the splitting of water and the selective reduction of NOx species. When considering the CeOx/TiO2 system, the two oxide components are prototypical lanthanide (CeO2) and transition metal (TiO2) compounds and have been extensively studied on their own. Catalytically, both offer excellent redox chemical properties including reducibility, stable oxidation states (Ce4+/Ce3+; Ti4+/Ti3+), and oxygen storage capacity. However, both structurally (CeO2 – fluorite versus TiO2 – anatase lattice) and electronically (Ce-4f versus Ti-3d valence levels), there are substantial differences between these two materials. Recent studies with powder catalysts show intermixing at the ceria-titania interface with a gain in the stability of Ce3+ over Ce4+. Ce3+ sites are also observed after depositing ceria nanostructures on a TiO2(110) substrate. This talk will discuss the characterization of these sites and will show that they are essential for the very good performance of metal/CeOx/TiO2 catalysts.

Controlling the nature of mixed-metal oxide catalysts at the nanometer level: CeOx/TiO2 and the importance of Ce3+ as an active site

251st National Meeting (2016)

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