Rare earth doping effect on the thermal stability of Ce0.35Zr0.60M0.05O2: insights from experiment and simulation

Abstract

CexZr1-xO2 (CZ) plays an important role in many environment catalytic fields such as automobile three-way catalysts (TWCs), but improving their thermal stability is still a great challenge. In this work, a strategy was proposed to enhance the thermal stability of CZ by combining experiment with ab-initio molecular dynamics (AIMD) method. It is found that the thermal stability of Ce0.35Zr0.60M0.05O2 (M represent La, Y, and Nd elements) could be adjusted by doping the suitable rare earth (RE) elements in the surface of CZ. With this strategy, the thermal stability of Ce0.35Zr0.60M0.05O2 (CZ-Y) with surface doping of Y is highest among these Ce0.35Zr0.60M0.05O2 samples. In comparison with the CZ sample without doping (specific surface area SSA=20.16 m2⋅g-1), CZ-Y exhibit superior thermal stability (SSA=26.83 m2⋅g-1) after thermal treatment (1100 °C/10 h). To give a deep insight into the RE doping effects, the thermal displacement rate (TDR) of Ce0.35Zr0.60M0.05O2 are further calculated by AIMD. It is found that CZ-Y has the lowest TDR values, which is beneficial for suppressing the thermal displacement of atoms and improving the thermal stability of CZ. This study provides a deep insight into the origin of rare earth (RE) doping effect on CexZr1-xO2 (CZ), which is of fundamental interest for the development of high performance CZ in practical applications.