Abstract:
In this work, a new approach to the preparation of heterostructured nanoparticles (NPs) based on bismuth silicates Bi$_2$SiO$_5$/Bi$_{12}$SiO$_{20}$ is proposed and implemented. This approach is based on solid-phase synthesis by annealing of a pre-homogenized mixture of $\beta$-Bi$_2$O$_3$ and SiO$_2$ powders in different ratios. For this purpose, industrial silica nanopowder and $\beta$-bismuth oxide NPs powder obtained by pulsed laser ablation (PLA) in air are used. The morphology, phase composition and optical properties of the obtained materials are studied. By changing the ratio of precursors, the powders similar in structure to single-phase bismuth silicates Bi$_2$SiO$_5$ and Bi$_{12}$SiO$_{20}$ as well as heterostructured NPs on their basis are obtained. The activity of the photocatalysts in the reactions of Rhodamine B (Rh B) decomposition and selective oxidation of 5-hydroxymethylfurfural (5-HMF) is estimated. The best photocatalytic activity is demonstrated by powders with a similar Bi$_2$SiO$_5$/Bi$_{12}$SiO$_{20}$ (or 4Bi:1Si) phase ratio. As a result of the analysis of the data obtained, the formation of a type II heterojunction is proposed.
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