Mesoporous structure of praseodymium-stabilized zirconia

Mesoporous PrOy–ZrO2 materials were obtained by coprecipitation process. XRD patterns and TEM images reveal pore size growth with increase in the calcining temperature. N2 adsorption–desorption isotherms of the PrOy–ZrO2 samples are indicative of type IV behavior characteristic of mesoporous materials (as evidenced by low-angle XRD patterns). PrOy–ZrO2 calcined at 500 and 650 °C show well-developed H2 type hysteresis loops, indicating the existence of ink-bottle-like pores with a narrow entrance and a large cavity. PrOy–ZrO2 calcined at 800 and 950 °C show H1 type hysteresis loops, which is often associated with porous materials known to consist of agglomerates of approximately uniform spheres, and hence to have narrow distributions of pore size. The phase analysis by Rietveld refinement method clearly shows the formation of cubic PrOy–ZrO2 solid solution from 500 to 950 °C.