Preparation of amphiphilic TiO2 Janus particles with highly enhanced photocatalytic activity

Stearic-acid-modified TiO 2 (STA-TiO 2 ) particles were prepared via the impregnation approach and used as a precursor for preparing TiO 2 Janus particles. The morphology, structure, and properties of the TiO 2 Janus particles were characterized using Fourier-transform infrared spectroscopy, ultraviolet-visible diffuse reflectance spectroscopy, thermogravimetric analysis, fluorescence microscopy, high-resolution transmission electron microscopy, contact angle analysis, dynamic light scattering, biological microscopy, X-ray photoelectron spectroscopy, and electrochemical impedance spectroscopy measurements. The results show that TiO 2 Janus particles can be successfully prepared via toposelective surface modification. STA grafted on the surface of TiO 2 enhances its hydrophobicity, promotes charge separation, and improves its adsorption capacity for organic compounds. The TiO 2 Janus particles strongly adsorb on an oil-water interface to form a stable Pickering emulsion. The degradation rates of high-concentration kerosene and nitrobenzene wastewaters when the photocatalyst is pure TiO 2 , STA-TiO 2 , or TiO 2 Janus particles are discussed and compared. The degradation rates were determined using an ultraviolet-visible spectrophotometer. It was found that the Pickering emulsion stabilized by the TiO 2 Janus particles exhibited the best photocatalytic performance; these Janus particles show promising potential for catalytic application. TiO 2 Janus particles were successfully prepared via toposelective surface modification. The particles adsorbed stably on the interface between pollutants and water, greatly improving the photodegradation efficiency of organic wastewater.