This research examines the structural and magnetic properties of monodomain cobalt ferrite nanoparticles with the formula (Co_1−xFe_x)^A[Fe_2−xCo_x]^BO₄. The particles were synthesized using various methods, including coprecipitation (with and without ultrasonic assistance), coprecipitation followed by mechanochemical treatment, microemulsion, and microwave-assisted hydrothermal techniques. The resulting materials were extensively analyzed using X-ray diffraction (XRD) and magnetic measurements to investigate how different synthesis methods affect the structure and cation distribution in nanoscale CoFe₂O₄. For particles ranging from 15.8 to 19.0 nm in size, the coercivity showed a near-linear increase from 302 Oe to 1195 Oe as particle size increased. Saturation magnetization values fell between 62.6 emu g⁻¹ and 74.3 emu g⁻¹, primarily influenced by the inversion coefficient x (0.58–0.85). XRD analysis revealed that as the larger Co²⁺ cations migrate from B- to A-sites (decreasing x), the lattice constants and inter-cation hopping distances increase, while the average strength of super-exchange interactions decreases. This study establishes a connection between the magnetic properties of the synthesized samples and their structural features. Importantly, this research demonstrates that careful selection of the synthesis method can be used to control the magnetic properties of these nanoparticles.

This study employed a novel synthetic approach involving a modified reverse co-precipitation method utilizing glacial acetic acid to synthesize α-Bi₂O₃. X-ray powder diffraction and scanning and transmission electron microscopy analyses revealed the formation of a rod-like α-Bi₂O₃ microstructure. The prepared material was utilized to modify a glassy carbon paste (GCP) electrode for the development of an electrochemical sensor for acetaminophen (APAP) detection using differential pulse voltammetry (DPV). Cyclic voltammetry studies revealed that the GCP@Bi₂O₃ electrode exhibited enhanced electrochemical properties compared to the bare GCP. The designed GCP@Bi₂O₃ sensor detected APAP in the linear concentration range from 0.05 to 12.00 µM, with LOQ and LOD of 36 nM and 10 nM, respectively. Additionally, the developed sensor demonstrated sufficient precision, repeatability, and selectivity toward APAP detection. The recovery values between the declared and found APAP content in a pharmaceutical formulation (Caffetin^®) displayed the advantageous accuracy, precision, and applicability of the GCP@Bi₂O₃ sensor and the developed DPV method for real-time APAP detection in pharmaceuticals, with minimal interference from the matrix effect.

This work is the first report of a very simple and fast one-pot synthesis of nickel oxide (NiO) and hematite (?-Fe2O3) nanoparticles by thermal decomposition of transition metal aqua complexes with camphor sulfonate anions. Obtained nanopowders were characterized by X-ray powder diffraction, Fourier transform IR analysis, scanning electron microscopy, and Energy-dispersive X-ray spectroscopy. X-ray powder diffraction confirmed the formation of high purity NiO and ?-Fe2O3 crystal phases. In the case of ?-Fe2O3, about five times larger average crystallite size was obtained. Fourier transform IR spectra of synthesized materials showed characteristic peaks for NiO and ?-Fe2O3 nanostructures. To visualize the morphology and the chemical composition of the final products Scanning electron microscopy and Energy-dispersive X-ray spectroscopy were performed. The thermogravimetric analysis was done for a better understanding of the general thermal behavior of precursor compounds. This easy-to-perform and fast preparation method opens a broad range of obtained materials? usage, particularly due to its economic viability

The effect of Ca2+ amount and sintering temperature on mechanical properties of geopolymer-brushite (GPB) binders was investigated. Brushite and raw abandoned kaolinite clay thermally transformed into metakaolin were used for GPB synthesis. The complete phase and structural analyses were performed by X-ray powder diffraction, and Fourier transforms infrared spectroscopy (FT-IR). The pore-filling effect as a consequence of Ca2+ ions incorporation into the hybrid geopolymer networks improved the compressive strength. On the other hand, the chosen biscuit sintering at 800 and 900oC caused the phase transformation of brushite into calcium pyrophosphate, which negatively affected the compressive strength of such materials. The obtained results indicate that the usage of relatively high sintering temperatures is not always the necessary step for producing geopolymer-based types of cement with prominent mechanical properties.