Hollow Spherical Hierarchical MoO3/SiO2–TiO2 Structures for Photocatalytic Decomposition of Organic Pollutant in Water

• Published in: Applied materials today Vol. 29; p. 101655
• Main Authors: Kuznetsova, Svetlana A., Khalipova, Olga S., Lisitsa, Konstantin V., Selunina, Liliya A., Khasanov, Victor V., Malchik, Alexandra G., Chen, Yu-Wen
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-12-2022
• ISSN: 2352-9407; 2352-9415
• DOI: 10.1016/j.apmt.2022.101655

•Spherical MoO3/TiO2–SiO2 composites with core/shell type, where the core is an α-MoO3 sphere and the shell is TiO2 anatase with SiO2 amorphous was synthesized.•Hierarchical structures in which layer are linked through oxygen (Ti-O-Mo and Si-O-Mo) results in lower oxygen vacancy concentrations in MoO3 (0.0425) and a reduced bandgap width (2.58 eV).•The MoO3/TiO2–SiO2 composites exhibit high photocatalytic activity (rate constant is 0.0645 min‒1).•The MoO3/TiO2–SiO2 layered spherical composites is a promising candidate material for photocatalytic decomposition of organic dyes in textile waste water.
In this study MoO3/TiO2–SiO2 layered spherical composites, having hierarchical structure, were synthesized on TOKEM-320Y anion exchanger template using by sol-gel methods. Properties of MoO3/TiO2–SiO2 composites were characterized by XRD, EDS, SEM, 3D X-ray microtomography, Raman, IR, DRS, BET, and PL techniques. The SEM, 3D X-ray microtomography and EDS analysis showed hollow spherical composites with diameters ranging from 200 to 400 μm with core/shell structure. The formation of TiO2–SiO2 shell on the MoO3 core results in lower oxygen vacancy concentrations in composite (0.0425) and a reduced bandgap width (2.56 eV in compare to 3.19 eV for MoO3 sample, which was analyzed through the UV–VIS DRS method). The performance of MoO3/TiO2–SiO2 composites was evaluated by photocatalytic degradation of methylene blue (MB) aqueous solution irradiated with an I2 excilamp (λmax = 312 nm). The photoabsorption energy properties of MoO3/TiO2–SiO2 composites are related to the interaction between TiO2–SiO2 and MoO3 which occurs through oxygen in Ti-O-Mo and Si-O-Mo. The MoO3/TiO2–SiO2 composites exhibited a much higher photocatalytic activity (rate constant is 0.0645 min‒1, degradation efficiency is 93% (20 min). This work demonstrates the relation between the formation of heterostructure in core/shell composite and its photocatalitic activity, providing fundamental guidance to improve photocatalytic performance of materials.
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