Solvent-induced synthesis of hierarchical TiO2 nanoflowers with tunable morphology by monolayer self-assembly for probing the photocatalytic performance

A solvothermal route was developed to synthesize hierarchical TiO2 nanoflowers with tunable morphology, macroporous and mesoporous structure, and larger surface areas by varying the ratio of N,N-dimethylformamide to isopropyl alcohol without using surfactant and template. Morphology and microstructure, textural, crystalline, optical and photoelectric properties were characterized to investigate thoroughly the correlation of features and photoactivity of catalysts. The photoactivity was evaluated for the degradation of phenol through analyzing the phenolic compounds. The catalysts exhibited significantly high photocatalytic activity with the degradation rate of phenol of 95%, and the decrease of total organic carbon (TOC) was 82 ± 3% under ultraviolet radiation (UV) for 180 min at room temperature. Meanwhile, the excellent cyclic stability and regenerability were obtained during five cycles and continued illumination. The enhanced photocatalytic activity probably was attributed to larger surface areas, hierarchical porous structure, effective generation and separation of the charge carriers, and outstanding light-harvesting ability.