Transformation of 2-D TiO2 to mesoporous hollow 3-D TiO2 spheres-comparative studies on morphology-dependent photocatalytic and anti-bacterial activity

• Published in: Microporous and mesoporous materials 2019-09, Vol.285, p.32-42
• Main Authors: Kaushik, Ravinder, Vineeth Daniel, P., Mondal, Prosenjit, Halder, Aditi
• Format: Article
• Language: English
• Subjects: Antibacterial activity; Bisphenol A degradation; Morphology-controlled synthesis; Photocatalysis; Pseudo-first-order kinetics
• ISSN: 1387-1811; 1873-3093
• DOI: 10.1016/j.micromeso.2019.04.068

Hierarchical nanostructures of anatase TiO2 with high active surface area has great significance in various applications. Here we have synthesized, highly photoactive hollow bowl like porous spheres of Titanium Dioxide (TiO2) (HBST) by a two-step synthesis procedure i.e. solvothermal strategy followed by thermal treatment. Solvothermally synthesized ultrathin nanoflakes TiO2 (7–8 nm thickness) was examined for the morphological and phase transformation using powder X-ray diffraction (PXRD), field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The nanoflakes, initially appeared to be assemble into a hierarchical nanostructure and finally converted to a compact spherical particle followed by hollow bowl like porous spheres of Titanium Dioxide (TiO2) (HBST) on heat treatment. Diffuse reflectance spectroscopy (DRS) measurement confirmed the band gap variation with respect to calcination conditions. Effect of obtained morphologies for photocatalytic and antibacterial activity was assessed using Bisphenol A (BPA) (a potent hazard, requiring immediate clearance) and E. coli (a potent microbial threat !!!). Both photocatalytic and antibacterial studies emphasized the conclusion, that hollow bowl morphology (HBST sample) is the best among all prepared morphologies. Mechanistic studies were carried out to reveal the role of photogenerated radicals and anions responsible for BPA degradation, where BPA degradation follow pseudo-first-order kinetics with rate constant value 0.00548 min−1. Results showed that HBST photocatalyst degraded nearly 89% of initial concentration of BPA in 360 min with high antibacterial efficiency towards E. coli on 1 h UV exposure. Reusability and repeatability tests were carried out to confirm the cyclic stability of the sample. [Display omitted] •Synthesis, mechanistic, multifunctional activity studies on hollow porous Titania.•Photocatalytic degradation study on industrial pollutants under UV light.•Comparative study on antibacterial activity by various morphology of TiO2.