A nanocrystalline compound nickel cobaltite (NiCo₂O₄) with the average size of crystals of ∼20 nm at 700°C has been synthesized using the method of combined crystallization of solutions of nitrates with the subsequent thermal and ultrasonic treatment. The optimal sintering mode of the NiCo₂O₄ powder (1300°C, 2 h, air) has been selected, and ceramics (60–65 nm) with open porosity of 25–30% have been prepared. The temperature and frequency dependences of the electrical conductivity of nickel cobaltite have been studied. It has been assumed that the high values of the electrical conduction and pseudo-capacity of NiCo₂O₄ are due to the variable valence of Ni and Co in oxides. It is recommended to use cobaltite nickel as an electrode material of a supercapacitor and a catalyst of the oxygen isolation in fuel elements.

Magnetic iron oxides have been widely used in bio- and agrotechnology, however, procedures of their synthesis can be improved. Magnetic nanopowders whose composition corresponds to magnetite–maghemite solid solutions have been obtained by chemical precipitation from aqueous solutions of iron(II, III) chlorides. Synthesis conditions (exposure to ultrasound, inert gas bubbling, heating to 70°C, keeping in mother liquor) have been shown by scanning and transmission electron microscopy and by computing unit cell parameters for magnetite and maghemite lattice to affect the size, shape, and aggregation extent of nanoparticles. No monophase magnetite and maghemite formed during the synthesis, a solid solution of mixed composition has precipitated.

Precipitation of nanopowders with mixed magnetite–maghemite composition was carried out under different conditions and with different separation techniques. The exact character of interactions of different iron oxide phases in the nanopowder was the main object of interest. The obtained nanopowders have spherical particles about 10–20 nm in size. Electron paramagnetic resonance (EPR) study showed that iron ions incorporate fully into magnetite and maghemite structures. The shape of the EPR line points out that single homogenous solid solutions were formed during synthesis. In the studied solid solutions, different ratios of vacancies and Fe²⁺/Fe³⁺ ratios were observed but in spite of different synthesis techniques in both cases, there were no additional diamagnetic structural phases presented.

Methods of the synthesis of nanostructured oxide films have been suggested for gas sensors based on zirconium and cerium dioxides with a cubic structure and crystallite size of 10–12 nm. The compositions in the CeO₂-ZrO₂ system having the highest sensitivity have been predicted, based on quantum-chemical calculations via the density functional method (DFT). These calculated data are correlated to the experimental results of the measurement of electroconductivity on air and in a reducing medium (CO₂ + CO). The obtained nanosized oxide films have a high response time (5–6 s) and sensitivity; they are promising as resistive sensors for the detection of media with reduced oxygen content. The method of computer simulation allows the reduction of the search period of new materials for gas sensors.