Rapid and Scalable Fabrication of TiO2@g-C3N4 Heterojunction for Highly Efficient Photocatalytic NO Removal under Visible Light

The TiO2@g-C3N4 heterojunction composites were successfully synthesized via one-step pyrolysis using commercial TiO2 and Urea. The photocatalytic performance was investigated by measuring the degradation of nitric oxide (NO) under visible light. The light absorption and bandgap of the materials were determined by diffuse reflectance spectroscopy (DRS), which confirmed the strong photocatalytic activity of the materials under visible light. The NO photodegradation efficiency of the composite was almost 90% under visible irradiation, the generation of by-products and nitrogen dioxide (NO2) were calculated to understand the conversion pathway of the NO during the photocatalytic reaction. Furthermore, the results of recycling indicated that the TiO2@g-C3N4 composite presents excellent stability. Besides, the morphology and the chemical compositions of the materials were observed by high-resolution transmission electron microscopy (HR-TEM) images. X-ray photoelectron spectroscopy (XPS). Raman spectroscopy was used to detect the structural vibrations of the materials. Through the electron spin resonance (ESR) and trapping tests, the photocatalytic mechanism of TiO2@g-C3N4 composite has also been proposed, in which superoxide radical anions play a significant role in NO removal.