Cerium–zirconium mixed oxide synthesized by sol-gel method and its effect on the oxygen vacancy and specific surface area

Abstract

In this study, cerium-zirconium mixed oxides were prepared using the sol-gel methodology with cetyltrimethylammonium bromide (CTAB) for tuning the specific surface area and pore volume. The composition of Ce0.8Zr0.2O2 (CZ) was selected as being one of the most active for soot oxidation, which is a concern as an environmental pollutant. The structural and morphological properties were investigated using EDXRF, XRD, SEM/EDS, Raman and N2 physisorption at low temperature. The catalytic test was evaluated by temperature-programmed oxidation coupled with mass spectrometry (TPO/MS). Any variation in the CTAB concentration during synthesis changed the particle size and surface area, indicating that the particle formation follows a mechanism in which the CTAB acts as capping agent. Additionally, the material synthesized with CTAB was found to have higher oxygen vacancy compared to the materials from the conventional sol-gel process. The catalytic test suggested that the material with the smallest surface area had the lowest temperature of oxidation (T50% ​= ​400 ​°C), which demonstrates that the oxygen vacancy parameter is essentially more important than the specific surface area itself.