Effects of Ni-Doping of Ceria-Based Materials on Their Micro-Structures and Dynamic Oxygen Storage and Release Behaviors

AbstractThe structural, textural, and dynamic oxygen storage/release behaviors of Ni 0.1 Ce 0.9 O x and Ni 0.1 Ce 0.6 Zr 0.3 O x (prepared by sol-gel method) are investigated by X-ray diffraction (XRD), Raman, H 2 -TPR, X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR), and CO/O 2 pulses with mass spectrometry studies. The dynamic oxygen storage capacity and rate are largely promoted by Ni doing, and the thermal stability of the sample is also enhanced. XRD and Raman results indicate that Ni 0.1 Ce 0.9 O x and Ni 0.1 Ce 0.6 Zr 0.3 O x have the fluorite-type cubic structure similar to CeO 2 . TPR, EPR, and XPS analyses reveal that the introduction Ni into ceria and ceria-zirconia mixed oxides strongly modifies the structural and textural properties, which influence the kinetics of bulk oxygen diffusion.Graphical AbstractThe dynamic oxygen storage capacity (DOSC) of Ni doped samples (Ni 0.1 Ce 0.9 O x and Ni 0.1 Ce 0.6 Zr 0.3 O x ) and reference samples (CeO 2 and Ce 0.67 Zr 0.33 O 2 ) were investigated with CO/O 2 transient pulses. The results show that Ce-based materials containing Ni oxides with variable valences contribute to the majority of DOSC and DOSR performances, and the stability of DOSC is obviously enhanced by Ni and Zr codoping.[IMAGE]