Graphitic carbon nitride was synthesized via thermolysis of urea and then ultrasonic exfoliated from colloidal solution to obtain phase pure ultrafine powder of g-C₃N₄. It was shown that ultrasonic-assisted exfoliation of the initial graphitic carbon nitride powder leads to an increase in its phase purity (PXRD), a change in the morphology (SEM), a decrease in the band gap from 2.93 eV to 2.85 eV (DRS) and an increase in the specific surface from 58.6 m²/g to 136.7 m²/g (BET). In addition, it was found that the exfoliated g-C₃N₄ is an effective catalyst for the process of electrocatalytic reforming – the hydrogen evolution from the water-alcohol solution. Based on volamperometry, it was found that the hydrogen overpotential of graphitic carbon nitride is equal to 249 mV (at 10 mA/cm²), and the Taffel slope is 112 mV/dec. The results of cyclic voltammetry of the electrode based on exfoliated g-C₃N₄ indicate its high stability, which allows us to consider the exfoliated graphitic carbon nitride as a promising basis of materials for electrocatalytic reforming of alcohols.

In this study, exfoliated g-C₃N₄/NiO nanocomposites were synthesized by the heat treatment of urea and subsequent ultrasonic exfoliation of the colloidal solution with the introduction of nickel acetate.

In this work, a simple solution combustion synthesis followed by heat treatment was proposed to produce nanocrystalline h-YbFeO3/o-YbFeO3 heterojunction and phase-pure o-YbFeO3. A detailed investigation on the formation process of h-YbFeO3 and o-YbFeO3 nanocrystals was carried out using a wide variety of methods, including EDS, SEM, PXRD, 57Fe Mössbauer spectroscopy, DRS. The most prospective samples of the h-YbFeO3/o-YbFeO3 nanocomposite and o-YbFeO3 nanopowder were examined towards the photo-Fenton decolorization of methyl violet (MV) under visible light. It was shown that the proposed approach allows for obtaining h-YbFeO3 and o-YbFeO3 nanocrystals with an average size of 15.7–21.1 nm and 41.1–65.5 nm, respectively, and with a specific surface area of up to 16 m2 g−1. It was found that the h-YbFeO3/o-YbFeO3 nanocomposite has a mesoporous structure and foam-like morphology, while the o-YbFeO3 nanopowder is non-porous and represented by agglomerates of individual nanoparticles with isometric morphology. Based on the DRS results, it was found that the band gap value was 2.05 eV and 2.16 eV for the h-YbFeO3/o-YbFeO3 and o-YbFeO3 samples, respectively, providing strong visible-light absorption of the samples. It was shown that the electron structure of the h-YbFeO3/o-YbFeO3 nanocomposite refers to I type heterojunction, leading to effective electron and hole transfer from o-YbFeO3 to h-YbFeO3 bands. This feature determines the higher photocatalytic activity of the h-YbFeO3/o-YbFeO3 nanocomposite as compared to pure o-YbFeO3 in the process of the Fenton-like decolorization of methyl violet under visible light with the pseudo-first-order reaction rate of 0.004848 min−1 and 0.003123 min−1, respectively. In conclusion, the mechanism of the photocatalytic decolorization of MV over the heterojunction nanocomposite was proposed to explain its high activity in the Fenton-like process.

In the presented work, heterostructured nanocomposites based on g-C₃N₄ and PrFeO₃ with different mass content of PrFeO₃ (0–10 wt%) were prepared by ultrasonic processing to study their photocatalytic activity in the process of antibiotic degradation under visible light. The study of phase composition, structural, morphological and textural characteristics carried out by powder X-ray diffraction, scanning electron microscopy and adsorption-structural analysis confirmed the presence of two phases - graphite-like C₃N₄ and orthorhombic PrFeO₃ with average crystallite sizes of 5 and 21 nm and mesoporous structure with specific surface area of 57.2–68.6 m²/g and average pore size of 20 nm. The measured values of the forbidden bandwidth for the obtained nanocomposites were ∼3 eV, indicating potential activity under visible light irradiation. The efficiency of antibiotic removal under visible light was evaluated in the degradation of TCHCl. It was found that 5 % PrFeO₃ content was optimal and increased the TOF by 5 times compared to pure g-C₃N₄. The results of photocatalytic test with absorbers showed that photocatalysis occurs by Z-scheme mechanism. The results obtained allow us to consider this nanocomposite as an effective and stable photocatalyst for pharmaceutical wastewater treatment.