Correlation of morphology with catalytic performance of CrOx/Ce0.2Zr0.8O2 catalysts for NO oxidation via in-situ STEM

The influence of drying condition on the formation of Ce0.2Zr0.8O2 was investigated and the NO oxidation efficiency over them was evaluated. These catalysts were investigated in detail by means of X-ray diffraction (XRD), High resolution transmission electron microscope (HR-TEM), Brunauer-Emmett-Teller (BET) surface area analysis, X-ray photoelectron spectroscopy (XPS) and NO(O-2) Temperature-programmed desorption (NO(O-2)-TPD). The results demonstrated that the slow drying rate caused by the decrease of the temperature and the use of the vacuum benefited for more Zr doped into CeO2 lattice and hence generated more Ce3+ on the surface, thus benefitting for the adsorption amount of O-2. TEM results display the special morphology of the catalysts, which prepared under the conditions of slow drying rate. Gas-cell in-situ STEM confirms that the slow drying rate and the nature of the solvent made the particles growing along the (111) facet and finally displayed the coralloid particles. The coralloid catalysts prepared at the low drying temperature in the vacuum oven exhibited the highest NO oxidation efficiency, which reached 50.54% at 350 degrees C. (C) 2015 Elsevier B.V. All rights reserved.