Structural and Redox Properties of Ce1–xZrxO2−δ and Ce0.8Zr0.15RE0.05O2−δ (RE: La, Nd, Pr, Y) Solids Studied by High Temperature in Situ Raman Spectroscopy

In situ Raman spectroscopy at temperatures up to 450 °C is used to probe the structural and redox properties of Ce1–xZrxO2−δ solids (x = 0–0.8) prepared by the citrate sol–gel and coprecipitation with urea methods. The anionic sublattice structure of the solids is dependent on the preparation route. The composition effects exhibited by the Raman spectra are adequate for characterizing the phases present and/or eventual phase segregations. For x = 0.5 the pseudocubic t″ phase occurs for the solid prepared by the citrate sol–gel method, while phase segregation (cubic, tetragonal) is evidenced for the corresponding material prepared by the coprecipitation with urea method. A larger extent of defects and interstitial O atoms is evidenced for the materials prepared by the citrate sol–gel method. The well-known “defect” (“D”) band around 600 cm–1 for CeO2 as well as for Ce1–xZrxO2−δ consists of at least two components: “D1” above 600 cm–1 and “D2” below 600 cm–1. Doping of Ce0.8Zr0.2O2−δ with rare earth cations...