Effect of temperature and atmosphere on thermolysis of Ce1-xPrx(HCOO)3 precursor for obtaining a palette of pigments based on praseodymium-doped ceria Ce1-xPrxO2

For the first time, the possibility of obtaining nanostructured Ce1-xPrxO2 oxides by the precursor method using mixed Ce1-хPrх(HCOO)3 (0 ≤ x ≤ 1) formates as a precursor was demonstrated. Thermal decomposition of precursors upon heating in air and inert atmosphere is a pseudomorphic process, i.e. the three-dimensional architecture of the crystalline aggregates of the precursor is inherited by the product of its thermolysis. For the first time, the patterns of formation of the morphology, composition, properties and nature of oxides formed as a result of thermal decomposition of Ce1-хPrх(HCOO)3 in an inert helium atmosphere, where both the composition of the precursor and the temperature of its heating are of great importance, have been revealed. The charge transfer band (O2−→Pr4+) determines the presence of red and red-brown coloration in Ce1-xPrxO2 powders. The reducing atmosphere resulting from the decomposition of the organic component of the precursor (HCOO−) to form CO and H2 causes a decrease in the Pr4+/Pr3+ ratio in the Ce1-xPrxO2 oxides, which greatly affects their color characteristics. The Ce1-xPrxO2 fluorite structure is retained for the composition with x = 0.5, and at higher praseodymium concentrations, other oxides are formed. Thus, the products of thermolysis of Ce0.25Pr0.75(HCOO)3 and Pr(HCOO)3 formates are the (Ce0.25Pr0.75)2O3 oxide with the cubic structure Ce2O3 and Pr2O3, the powders of which have a yellow-green and yellow color, respectively. The following methods were used to describe the properties of the obtained samples: X-ray diffraction, SEM and EDX, Raman spectroscopy, excitation and luminescence spectra, UV–Vis–NIR spectra, and the electron density functional method. [Display omitted] •Ce1-xPrxO2 were prepared by a precursor method.•According to XRPD, Infrared and Raman data, Ce1-xPrx(HCOO)3 are isostructural.•The difference in the optical and spectral properties of samples obtained by heating precursors in air and in He.•Ce1-xPrxO2 oxides with a color range from light pink to reddish brown were synthesized.•The optical and spectral properties of samples obtained by heating precursors in air and in He have differences.