Optimization of reaction parameters affecting crystal phase growth and purity of BaCeO3 and BaCe1-xYbxO3-delta nanopowders and investigating high protonic conductivity of sulfonated poly(ether ether ketone) - BaCe0.85Yb0.15O3-delta composite membrane

摘要

Pure and ytterbium-doped BaCeO3 nanostructures were synthesized by solid-state reaction with the mixtures of Ba(NO3)(2), BaCO3, (NH4)(2)Ce(NO3)(6), and Yb2O3 at 800 degrees C for 10 and 24 h. Doping of ytterbium ions in the BaCeO3 host matrix has been studied and confirmed using powder X-ray diffraction. The results from the Rietveld analysis indicated that the sample has a main BaCeO3 structure with the space group of Pm (3) over barm. Through intensive experiments and analysis, optimum reaction conditions for the synthesis of doped nanoparticles including the crystal phase impurity and reaction time are proposed. The results of the study showed that for the reaction time of 24 h, BaCO3 reacted more effectively with (NH4)(2)Ce(NO3)(6) than Ba(NO3)(2) did. On the other hand, the purity values of 97% and 95% were obtained for pure and Yb3+ doped BaCeO3 samples, respectively. Field emission scanning electron microscope images revealed that the synthesized BaCeO3 nanomaterials have mono-shaped sphere morphology. Furthermore, ytterbium-doped nanoparticles were incorporated into the matrix of sulfonated poly(ether ether ketone) (SPEEK) membranes (SPYb) with the aim of enhancing proton conductivity. The prepared SPYb nanocomposite membrane containing 1.7 wt.% of BaCe0.85Yb0.15O3-delta nanoparticles exhibited a high proton conductivity (67 mS/cm) at 80 degrees C.