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Nanoparticles of transition metal chalcogenides are promising materialds for creating fairly cheap and efficient electro- and photocatalysts for producing hydrogen by splitting water. The method of pulsed laser ablation in liquid makes it possible to obtain nanoparticles, whose characteristics depend on the chemical nature of the ablated targets and the composition of liquid. Nanoparticles obtained by ablation of a WSe2 target with nanosecond laser pulses in water and isopropyl alcohol are studied. The size of the nanoparticles varies in the range from ~20 to ~200 nm. During laser ablation in water, the formation of tungsten oxide nanoparticles dominates. Nanoparticles obtained by laser ablation in alcohol contain nanophases with different valences of tungsten: W6+ (WO3), W5+ (W–Se–O), W4+ (WSe2), and W0. No obvious signs of carburization of these nanoparticles are found. In both cases, selenium not reacted with tungsten is released in the form of a crystalline and/or amorphous nanophase. The possibility of applying the created nanoparticles as photocatalysts for the hydrogen evolution reaction is analyzed. [ABSTRACT FROM AUTHOR]

The results of studying the morphology, porous structure, and corrosion and diffusion properties of boehmite-containing calcium phosphate coatings formed by microarc oxidation on titanium substrates are presented. Boehmite nanoparticles obtained as a result of the AlN hydrolysis were deposited on the surface of microarc coatings with a developed relief. With an increase in the duration of the preliminary ultrasonic treatment (UST) of the AlN suspension in the interval of 20–60 min, the size of agglomerates of boehmite nanoparticles on the coating surface is decreased from 200 to 40 μm. The surface porosity of the modified coatings and the area occupied by boehmite particles are decreased from 36 to 33% and from 27 to 10%, respectively. Agglomerates with boehmite nanoparticles after 60 min of UST of an AlN powder suspension are distributed in the coating more uniformly than after 20 min of treatment. When the duration of UST of the initial suspensions is increased, the effective diffusion coefficients of the model biological fluid in porous coatings is decreased from 7.98 × 10–11 to 7.25 × 10–11 m2/s. Modification of calcium phosphate coatings with boehmite nanoparticles by varying the duration of UST of AlN powder increases the corrosion resistance of the surface layers. [ABSTRACT FROM AUTHOR]