Physicochemical properties of praseodymium hydroxide and oxide nanorods

[Display omitted] •Pr(OH)3 nanorods were synthesized by a hydrothermal method.•Pr6O10 nanorods were obtained by a post-annealing method.•Pr(III) changed to Pr(IV) after annealing.•The physicochemical properties were fully examined.•Hydrogen reduction and CO oxidation profile were newly revealed. We synthesized hexagonal phase Pr(OH)3 nanorods by a hydrothermal method and obtained cubic phase Pr6O11 by post-thermal annealing at above 550°C. Pr(OH)3 nanorod growth was found to occur in the [001] direction. Upon thermal annealing, the oxidation state of Pr(III) was changed to Pr(III, IV). The physicochemical properties were fully examined by scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD) crystallography, UV–Visible–NIR absorption, differential scanning calorimetry/thermogravimetric analysis (DSC/TGA), X-ray photoelectron spectroscopy (XPS), and temperature-programmed reduction (TPR) and CO oxidation activity tests.