Improving the dispersion of CeO2 on γ-Al2O3 to enhance the catalytic performances of CuO/CeO2/γ-Al2O3 catalysts for NO removal by CO

Acetic acid (HAc) aqueous was used as solvent in wetness impregnation to prepare CeO2-modified gamma-Al2O3 support. With the help of HAc, the dispersion of CeO2 on gamma-Al2O3 is significantly improved and the size of CeO2 nanoparticles can be controlled through tuning the concentration of HAc aqueous. XPS analysis shows that the percentages of Ce3+ in CeO2 nanoparticles will vary with the size. Then we load CuO on the as-prepared CeO2-modified gamma-Al2O3 support and choose NO reduction with CO as a probe reaction to investigate the influences of impregnation solvent on the catalytic properties. The results demonstrate that the CuO/CeO2/gamma-Al2O3 prepared in the solvent with volume ratio of 20:1 (H2O:HAc) has the highest activity in NO + CO reaction. Combing the structural characterizations and catalytic performances, we think that the size of the CeO2 nanoparticles should be a key factor that affects the activities of CuO/CeO2/gamma-Al2O3. Furthermore, CuO dispersed on CeO2 nanoparticles with an average size of ca. 5 nm should be the highest active sites for NO + CO reaction. (C) 2014 Elsevier B.V. All rights reserved.