• Nanocomposite of Ni-Cr oxide was synthesized through the chemical co-precipitation approach • The morphological and physical properties of products were assessed thoroughly. • The possible chemical reactions through synthesis were proposed. • NiO and NiCr2O4 were formed with an average particle size of <30 nm. • Nanocomposite powders showed a weak ferro/ferrimagnetic signal with a fairly dominant superparamagnetic feature. NiO-NiCr₂O₄ nanocomposites are promising materials for photocatalytic, magnetic, and energy storage applications due to their tunable structural and physical properties. Ni-Cr oxide nanocomposites with different Ni/Cr ratios (50-50, 60-40, 70-30) were synthesized via chemical co-precipitation. The products were characterized by XRD, FTIR, FESEM, EDS, VSM, and UV-Vis spectroscopy. Crystallite size, lattice strain, and stress were evaluated using Scherrer, Williamson–Hall (UDM, USDM, UDEDM), and Size-Strain Plot (SSP) methods, with SSP identified as the most reliable approach for interpreting composition-dependent trends. The results confirmed the formation of NiO and NiCr₂O₄ phases with uniform elemental distribution and average particle sizes below 30 nm. Increasing NiO content led to a decrease in crystallite size and lattice strain. Magnetic characterization revealed dominant superparamagnetic behavior with weak ferro/ferrimagnetic signals. Coercivity increased from 128 to 252 Oe with higher NiO content, while the maximum saturation magnetization (0.291 emu/g) was observed for the intermediate composition (60-40). The optical band gap increased from 2.84 to 2.97 eV with rising NiO ratio, confirming the tunable semiconductor nature of the nanocomposites.
Javadi et al. (2026) studied this question.