Facile synthesis of F-doped g-C3N4/Bi2Fe4O9 heterostructure with Z-scheme for enhanced photocatalytic performance in NO oxidation

Graphitic carbon nitride (g-C3N4) with fluorine (F) doping was synthesized by a hydrothermal technique, and F-doped g-C3N4/Bi2Fe4O9 composites were synthesized by electrostatic self-assembly technique. The crystal structures were studied by X-ray diffraction, the morphology was determined by transmission electron microscope images, and the F doping was verified by energy dispersive X-ray analysis, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The N-2 adsorption/desorption results showed that introducing Bi2Fe4O9 nanoparticles into F-doped g-C3N4 reduced the specific surface area and volume of the pores. This could be attributed to the Bi2Fe4O9 nanoparticles partially blocking the pores of F-doped g-C3N4. The photocatalytic performance of F-doped g-C3N4/Bi2Fe4O9 composites was studied by oxidizing NO under visible irradiation. The photocatalytic performance indicated that the presence of Bi2Fe4O9 increased the photocatalytic activity of F-doped g-C3N4 by up to similar to 100%. The increased photocatalytic performance could be ascribed to a decreased combination rate of the charge carriers. Moreover, scavenger testing study showed that the reactive species, including h(+), O-2, and center dot O-2(-), played important roles in the photocatalytic reactions.