Transformation of novel TiOF2 nanoparticles to cluster TiO2-{001/101} and its degradation of tetracycline hydrochloride under simulated sunlight

The anatase type cluster TiO2-{001/101} was rapidly generated by a one-step hydrothermal method. The transformation process of coral-like TiOF2 nanoparticles to cluster TiO2-{001/101} was investigated for the first time, and the sensitization between cluster TiO2-{001/101} and tetracycline hydrochloride (TCH) was also discussed. The degradation rate of TCH by cluster TiO2-{001/101} under simulated sunlight was 92.3%, and the total removal rate was 1.76 times that of P25. Besides, cluster TiO2-{001/101} settles more easily than P25 in deionized water. The study showed that cluster TiO2-{001/101} derived from coral-like TiOF2 nanoparticles had a strong adsorption effect on TCH, which was attributed to the oxygen vacancy (Ov) and {001} facets of cluster TiO2-{001/101}. The strong adsorption effect promoted the sensitization between cluster TiO2-{001/101} and TCH, and widened the visible light absorption range of cluster TiO2-{001/101}. In addition, the fluorescence emission spectrum showed that cluster TiO2-{001/101} had a lower luminous intensity, which was attributed to the heterojunction formed by {001} facets and {101} facets that reduces the recombination rate of carriers. It should be noted that cluster TiO2-{001/101} still has good degradation performance for TCH after five cycles of degradation. This study provides a new idea for the synthesis of cluster TiO2-{001/101} with high photocatalytic performance for the treatment of TCH wastewater.