Correlations between Oxygen Uptake and Vacancy Concentration in Pr-Doped CeO₂

Area of Science:

• Materials Science
• Catalysis
• Solid State Chemistry

Background:

• Cerium oxide (CeO2) is a crucial material in catalysis due to its oxygen storage capacity.
• Modifying CeO2 with other elements can further enhance its properties.
• Praseodymium (Pr) doping in CeO2 is explored for improved oxygen handling.

Purpose of the Study:

• To investigate the effect of Praseodymium (Pr) doping on the oxygen uptake of Cerium oxide (CeO2) materials.
• To correlate oxygen uptake with material characteristics, including defects and oxidation states.
• To determine the optimal Pr content for enhanced oxygen storage.

Main Methods:

• Thermogravimetric analysis (TGA) to measure oxygen uptake at 420 and 600 °C.
• X-ray diffraction (XRD) and scanning transmission electron microscopy (STEM) for material characterization.
• Raman spectroscopy, ultraviolet-visible spectroscopy (UV-Vis), and electron energy loss spectroscopy (EELS) to identify defects and oxidation states.

Main Results:

• The 20% Pr-CeO2 sample exhibited the highest oxygen uptake at both tested temperatures.
• Raman and UV-Vis spectroscopy confirmed the presence of Pr3+ cations, attributed to oxygen uptake.
• EELS analysis revealed that increasing Pr content significantly increased oxygen vacancy concentration without a notable change in Ce3+ concentration.

Conclusions:

• Praseodymium doping enhances the oxygen uptake capability of Cerium oxide.
• The increased oxygen vacancy concentration, driven by Pr addition, is responsible for the improved oxygen storage.
• The 20% Pr-CeO2 composition demonstrates superior performance for oxygen handling applications.