Characterization and optimization of Ce0.6Zr0.4−x Mn x O2 (x ≤ 0.4)

Abstract

The need of high-oxygen storage material for the potential use of three-way catalyst (TWC) has increased over the years. Ceria and ceria-based materials were found to be utilized in TWC application due to their redox property, which was observed to be decreased due to its structural instability at high temperature. The objective of the present work is to increase the oxygen storage capacity (OSC) of the ceria by incorporating Zr4+ and Mn4+ into its lattice. A solid solution of nanostructured Ce0.6Zr0.4−xMnxO2 (0.0 ≤ x ≤ 0.4) (CZM) was synthesized using a sol–gel technique and the concentration of Zr4+ and Mn4+ was optimized based on its higher OSC. The formation of homogeneous CZM solid solutions was confirmed through XRD analysis, where the crystal size was observed to be varied from 2.7 to 3.8 nm. The OSC band of the samples and the lattice defects were confirmed using Raman spectroscopic studies. The OSC of the samples was computed using thermogravimetric analysis by cyclic heating process and it was found to be varied from 0.0722 to 0.1799 µmol/gram of CeO2. Ce0.6Zr0.2Mn0.2O2 solid solution (CZM2) was found to have the highest OSC among all the compositions studied and the same was confirmed by thermomechanical analysis. The magnetic characteristics of CZM were also confirmed. It is concluded that CZM2 can be considered as a potential catalyst because of its high OSC and structural stability.