A platelet-like CeO₂ mesocrystal enclosed by {100} facets: Synthesis and catalytic properties

Platelet-like CeO₂ mesocrystals, constituted of 4-5 nm fused nanoparticles with interparticular voids along a common [002] axis, have successfully been synthesized through a benzyl alcohol-assisted solvothermal synthesis, followed by a topotactical transformation at 400 C. The resulting CeO₂ mesocrystal superstructure is enclosed by Tasker III type {100} facets. H₂-TPR suggested that the as-made CeO₂ mesocrystal surfaces are covered by reactive oxygen vacancies. Such oxygen vacancies can activate oxygen at low temperatures (<200 C), and thereby catalyze CO and benzene oxidation effectively. Remarkably, the CO oxidation activity of CeO ₂ mesocrystal is 220 % as high as the traditional nanoparticle sample and a reaction rate of 0.53 μmol g _cat ^-1 s ^-1 for CeO₂ mesocrystal at 160 C has been achieved. Such a rate is even higher than the best value reported previously (0.51 μmol g _cat ^-1 s^-1 for CeO₂ nanorods). A similar superior catalytic property of CeO₂ mesocrystals was also observed in the catalytic oxidation of more recalcitrant benzene. Graphical Abstract: The formation scheme of mesocrystal CeO₂ enclosed by Tasker III type {100} facets and the corresponding catalytic CO oxidation activity. [Figure not available: see fulltext.]