Microflowery, Microspherical, and Fan-Shaped TiO2 Crystals via Hierarchical Self-Assembly of Nanorods with Exposed Specific Crystal Facets and Enhanced Photocatalytic Performance

In this paper, khaki titanium dioxide (TiO2) crystals via hierarchical self-assembly of nanorods with different morphologies and specific exposed crystal facets were prepared for the first time by using a TiCl3 treatment process in the presence and absence of morphology-controlling agents. The crystal structure, morphology, microstructure, specific surface area, and separation efficiency of photogenerated electron-hole pairs of the synthesized TiO2 crystals were characterized. The photocatalytic and recycled performances of the synthesized TiO2 crystals in the presence of shape-controlling agents, such as ammonium sulfate (AS), ammonium carbonate (AC), and urea, and the absence of shape-controlling agents (the obtained TiO2 crystals were expressed as AS-TiO2, AC-TiO2, urea-TiO2, and No-TiO2, respectively) were evaluated and compared with the commercial TiO2 (CM-TiO2) crystals. The AS-TiO2 microspheres with exposed uncertain facets exhibited enhanced photocatalytic activity for the degradation of methylene blue solution, which can be attributed to the combined effect of the anatase phase structure, relatively larger specific surface area, and the effective separation of the photogenerated electron-holes.

Automated summary

In this paper, khaki titanium dioxide (TiO2) crystals with different morphologies and specific exposed crystal facets were prepared for the first time by using a TiCl3 treatment process in the presence and absence of morphology-controlling agents. The synthesized TiO2 crystals showed enhanced photocatalytic activity due to the combined effect of the anatase phase structure, relatively larger specific surface area, and the effective separation of the photogenerated electron-holes.