Synthesis and Characterization of Anatase TiO2 Microspheres Self-Assembled by Ultrathin Nanosheets.

Jian Di,Zhuoyu Liu,Xing Ding,Haibo Yan

doi:10.3390/ma14112870

Jian Di, Zhuoyu Liu + Show 2 more

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https://doi.org/10.3390/ma14112870

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Abstract

In this paper, we report a novel and simple method for synthesizing the microspheres self-assembled from ultrathin anatase TiO2 nanosheets with a high percentage of (001) facets via the hydrolysis process of the single-reagent (potassium fluorotitanate). We then used optical microscopy, scanning electron microscopy, and high-resolution confocal laser Raman spectroscopy to characterize the microspheres generated under different conditions. The study found that the size of the anatase TiO2 microspheres synthesized was 0.5–3 μm. As the synthesis time increased, the corroded surface of the microspheres gradually increased, resulting in the gradual disappearance of the edges and corners of the anatase nanosheets. The exposure percentage of the (001) facets of ultrathin anatase nanosheets synthesized for 2 h at 180–200 °C are close to 100%. The microsphere whose surface is completely covered by these anatase nanosheets also has nearly 100% exposed (001) facets. This new anatase nanosheet-based self-assembled microsphere will have great application potential in pollution prevention, environmental protection, and energy fields.

Highlights

Introduction and Stefano LettieriNanocrystalline titanium dioxide (TiO2 ) has good chemical and physical stability and excellent photocatalytic performance [1,2,3]
They clearly display that the anatase nanosheets and corners (Figure 3d); by contrast, those nanosheets synthesized at 200 ◦ C for 5 h were microspheres synthesized by the precipitation damaged and loston-site most of their edgeshydrothermal and corners, method making have betterbetter roundness for the crystallinity, shapes, and dimensions than those synthesized by the drop-casting deposimicrospheres (Figure 3e,f); the size of the nanosheets synthesized was about 1–2 μm
Controlling the synthesis time is a nano-TiO2, leading to the formation of many small, xenomorphic, and fragmentary anatase nanocrystals (Figure 4). Both the methods can synthesize the anatase nanosheet-based microspheres with the high exposed (001) facets, it is evident that the microspheres synthesized by the on-site precipitation hydrothermal method have a more stable structure and better physicochemical properties as well as photocatalytic and photoelectric performance [1,3]

Summary

Introduction

Nanocrystalline titanium dioxide (TiO2 ) has good chemical and physical stability and excellent photocatalytic performance [1,2,3]. Anatase nano-TiO2 truncated octahedron, rod, wire, tube, belt, sheet, film, and sphere structures were synthesized [1,6]. For anatase nano-TiO2 , theoretical and experimental studies have demonstrated that the (001) facets are highly reactive towards photocatalytic performance [6]. The anatase nano-TiO2 spheres usually have a higher photocatalytic capability than other nanostructures and can be widely used in pollution prevention and environmental protection [8,9,10,11,12]. A flower-like TiO2 nanosphere structure with highly exposed (001) facets was synthesized through a hydrothermal reaction of titanium powder, hydrofluoric acid, and Received: 26 April 2021

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