A New Approach to Single-Step Fabrication of TiO -CeO Nanoparticles

Mixed metal oxide (MMO) nanoparticles (NPs) are hybrids consisting of two or more nanoscale metal oxides. Advantages of MMO NPs over single metal oxides include improved catalytic activity, enhanced electrical and magnetic properties, and increased thermal stability due to the synergy of the different oxide components. This study presents a novel fabrication route for TiO₂-CeO₂ NPs enriched with oxygen vacancies using a Haberland-type gas aggregation cluster source. The NPs, deposited from different segmented Ti/Ce targets under varying O₂ addition, were examined with respect to final composition, morphology, and Ti, Ce surface oxidation states. Particle formation mechanisms are proposed for the observed morphologies. Additionally, available O₂ during deposition and its impact on the formation of defective sites were investigated. Defective sites in TiO₂-CeO₂ NPs were analyzed using transfer to X-ray photoelectron spectroscopy and transmission electron microscopy without contact to ambient oxygen. The incorporation of Ce to the target exhibits synergistic effects on the synthesis process. Segmented Ti/Ce targets enable the deposition of a broad range of mixed oxide NPs with diverse compositions and morphologies at considerably enhanced deposition rates, which is vital for practical applications. The presented fabrication approach is expected to be applicable for a broad variety of MMO NPs.