Gold supported on ceria nanoparticles and nanotubes Original Research Article

The ceria nanotubes with different size have been prepared via a hydrothermal treatment of CeO2 nanoparticles at 120 °C with two different NaOH concentrations (5 or 10 M) for 36 h. The synthesized ceria samples characterized by SEM, TEM, XRD, and UV–visible spectroscopy were used as supports for Au/CeO2 catalysts preparation by DP technique using HAuCl4 as gold precursor and urea as precipitation agent. The formation of gold nanoparticles (Au NPs) has been studied by TEM, in situ UV–visible–mass analysis at temperature programmed reduction and XPS spectroscopy. Three distinguishable steps in the formation of Au NPs accompanied by profound ceria reduction particular for ceria nanotubes have been found. Au NPs stabilized on the ceria nanotubes have been characterized with higher activity in CO oxidation than those supported on ceria nanoparticles. The structure and redox treatment of ceria nanotubes affects size of Au NPs and their catalytic activity in CO oxidation. Pre-oxidized Au/CeO2-nanotubes manifest the highest activity in CO oxidation.