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In this research study, a thermal treatment approach based on a novel single-step has been utilised to addresses the synthesis of binary NiO0.5 Cr2O30.5 nanoparticles. Characteristics of these binary metal oxide nanoparticles were examined by employing appropriate characterization tools. Sample patterns of X-ray diffractions were used, calcined with temperature (Temp), set to 500 °C revealed the existence of face-centred cubic (fcc) and hexagonal crystalline structures (hcs). It was noted that with a rising calcination temperature, the nanoparticle dispersal was enhanced further. On the other hand, TEM micrographs have been used to calculate the size of the mean particle. It was found that there was a rising tendency with the increased calcination temperature and this the growth of the mean particle. Increased particle size inherited a rise of nanoparticles' photoluminescence intensity, as suggested by recorded spectra, and various energy band gaps. This result would have been reduced as an effect once calcination temperature was increased. Resulting NiO0.5 Cr2O30.5 nanoparticles could be used in the realm of semiconductors and energy applications.

A binary (CuO)0.6 (CeO2)0.4 nanoparticles were prepared via thermal treatment method, using copper nitrate, cerium nitrate as precursors, PVP as capping agent and de-ionized water as a solvent. The structures, morphology, composition of the element and optical properties of these nanoparticles have been studied under different temperatures using various techniques. The XRD spectrum of the samples at 500 °C and above confirmed the existence of both monoclinic (CuO) and cubic fluorite (CeO2) structures. The findings of FESEM and TEM exhibited the average practical size and agglomeration increment with an elevation in the calcination temperature. The synthesized nanoparticles were also characterized by FTIR, which indicated the formation of binary Cu−O and Ce−O bonds. The EDX analysis was performed to indicate the chemical composition of the sample. The double energy band gaps of (CuO)0.6(CeO2)0.4 reduction with rising calcination temperature, can be referred to the enhancement of the crystallinity of the samples. PL intensity of (CuO)0.6(CeO2)0.4 nanoparticles peaks, which increased with the elevation of the calcination temperature to 800 °C was observed from the PL spectrum; this was due to the increment of the particle size that occurred. Keywords: CuO nanoparticles, CeO2 nanoparticles, Calcination temperatures

An aqueous medium composed of polyvinylpyrrolidone (PVP) and cerium nitrates at calcination temperature was utilised in the production of cerium oxide (CeO2) semiconductor nanoparticles. A variety of analytical approaches was utilized to examine the structural, morphological and optical characteristics of the resulting nanoparticles. Differential thermal (DTA) and thermogravimetric (TGA) analyses, indicated that the best calcination temperatures for achieving CeO2 nanoparticle production were more than 485 °C. The results from Fourier-transform infrared (FTIR) verified the formation of a crystalline structure after calcination procedures were performed to remove residual organic compounds. Additionally, results from X-ray diffraction (XRD) analysis confirmed the cubic fluorite structure of the CeO2 produced. Samples were also analysed by energy dispersive spectroscopy (EDXA) which indicated the existence of O and Ce in the samples. Field emission scanning electron microscopy (FESEM) was used in the characterisation of nanoparticle morphological features. Transmission electron microscopy (TEM) was employed to estimate typical nanoparticle and distribution within sample. This analysis indicated that mean particle sizes were inversely correlated with PVP concentration, with nanoparticle sizes ranging between 12 ± 7 nm at 0.03 g/mL PVP and 6 ± 2 nm at 0.05 g/mL PVP. These results corroborated those obtained by XRD analysis. A UV–vis spectrophotometer was utilised in the demonstration of optical properties and to examine the band gap energy of samples. The potential UV-shielding properties of the nanoparticles were demonstrated by the observed blue shift of the estimated optical energy band, i.e. from 3.35 to 3.43 eV, whilst PL spectra results indicated that decreasing particle size was associated with diminishing photoluminescence intensity. Keywords: Cerium oxide nanoparticles, Heat treatment technique, Structural properties, Optical properties