The Preparation of {001}TiO2/TiOF2 via a One-Step Hydrothermal Method and Its Degradation Mechanism of Ammonia Nitrogen

{001}TiO2/TiOF2 photocatalytic composites with a high activity {001} crystal plane were prepared by one-step hydrothermal methods using butyl titanate as a titanium source and hydrofluoric acid as a fluorine source. X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), raman spectroscopy, N-2 adsorption-desorption curve (BET), UV-Vis diffuse absorption spectroscopy (UV-Vis DRS), X-ray photoelectron spectroscopy (XPS), and fluorescence spectroscopy (PL) were used to evaluate the structure, morphology, specific surface area, optical properties, and photocarrier separation ability of {001}TiO2/TiOF2. Ammonia nitrogen was taken as the target pollutant, and the degradation performance of the catalyst was investigated. The results show that hydrofluoric acid improves the content of {001} crystal plane of TiO2 with high activity; it also improves the specific surface area and dispersion of the composite material and adjusts the ratio of {001}TiO2 to TiOF2 in the composite material to enhance the absorption capacity of the composite material and reduce the band gap width of the composite material. The degradation rate of ammonia nitrogen by 100 mg F15 is 93.19% when the initial concentration of ammonia nitrogen is 100 mg/L and pH is 10. Throughout the reaction process, the {001}TiO2/TiOF2 composite produces superoxide anion radical (center dot O-2(-)) and hydroxyl radical (center dot OH) to oxidize NH3 center dot H2O and generate N-2 accompanied by a small amount of NO3- and NO2-.

Automated summary

TiO2/TiOF2 photocatalytic composites with a high activity {001} crystal plane were prepared using one-step hydrothermal methods. The use of hydrofluoric acid improved the specific surface area and dispersion of the composite material, and adjusted the ratio of {001} TiO2 to TiOF2, resulting in enhanced absorption capacity and reduced band gap width. The degradation rate of ammonia nitrogen by the catalyst was investigated, and the results showed promising performance.