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