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 CeO2 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. The formation scheme of mesocrystal CeO2 enclosed by Tasker III type {100} facets and the corresponding catalytic CO oxidation activity.