Comparative Studies of Nanoparticles Formed by Pulsed Laser Ablation of WSe₂ in Water and Alcohol

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.