A series of CuO/CeO₂catalysts were successfully synthesized via solution combustion method (SCS) using different fuels and tested for CO oxidation. The catalysts were characterized by energy-dispersive X-ray analysis (EDXA), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), N₂adsorption-desorption isotherms and H₂temperature-programmed reduction (H₂-TPR). It was found that the used fuels strongly affected the characterization and the low-temperature reduction behavior of CuO/CeO₂catalysts. The CuO/CeO₂-urea catalyst exhibited higher catalytic activity toward CO oxidation (t₅₀=120∘C,t₁₀₀=159∘C) than the 5 other synthesized catalysts. In addition, the CuO/CeO₂-urea catalyst displayed high stability for CO oxidation during five cycles and water resistance. The enhanced catalytic CO oxidation of the synthesized samples can be attributed by a combination of factors, such as smaller crystallite size, higher specific surface area, larger amount of amorphous copper(II) oxide, more mesoporous and uniform spherical-like structure. These findings are worth considering in order to continue the study of the CuO/CeO₂catalyst with low-temperature CO oxidation.

In this paper, powders consisting of o-EuFeO₃ nanoparticles were obtained by the co-precipitation method using two different precipitating agents (NH₃ and (NH₄)₂CO₃ solutions; corresponding products were denoted as samples S.1 and S.2, respectively) and followed by annealing for 1 h at 750, 850, and 950 °C. The magnetic, optical, and physicochemical characteristics of S.1 and S.2 were evaluated by means of EDXS (energy dispersive X-ray spectroscopy), PXRD (powder X-ray diffraction), TG/DSC (thermogravimetry/differential scanning calorimetry), FTIR (Fourier-transform infrared spectroscopy), TEM (transmission electron microscopy), UV-Vis DRS (Ultraviolet–Visible diffuse reflectance spectroscopy), and VSM (vibrating-sample magnetometry). The o-EuFeO₃ structure was shown to be stable at annealed temperatures, and t = 850 °C is recommended for synthesizing such substances. The average size of o-EuFeO₃ crystals is around 27 (S.1) and 34 nm (S.2). The results revealed a homogeneous distribution of the main elements on the samples’ surfaces, with morphology consisting of isometric and highly agglomerated nanoparticles. The bandgap value (E_g) of the synthesized samples was 2.31 (S.1) and 2.39 eV (S.2). Besides, these nanoparticles appeared to possess paramagnetic behavior.