Simultaneous synthesis-immobilization of Ag nanoparticles functionalized 2D g-C3N4 nanosheets with improved photocatalytic activity

A series of Ag/g-C3N4 photocatalysts were prepared by a simple method. Ag nanoparticles were simultaneously synthesized and immobilized during the synthesis of 2D g-C3N4 nanosheets (g-C3N4-NS). The as-prepared samples were characterized by powder X-ray diffraction (XRD), Fourier transform infrared spectra (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS) and UV-vis diffuse reflectance spectroscopy (DRS) spectra. The photocatalytic activities of as-obtained photocatalysts were measured by the degradation of Rhodamine B under visible-light irradiation. The photocatalytic RhB degradation experiments indicated that the 2% Ag/g-C3N4-NS could degrade 98% of RhB under 50 min visible-light irradiation, and the 2% Ag/g-C3N4-NS composites possessed the highest kapp value (0.0587 min−1), which was approximately 6.33 times larger than g-C3N4 nanosheets (0.00927 min−1) and 8.5 times larger than 2% Ag/g-C3N4-bulk (0.00691 min−1). The photocatalytic RhB degradation experiments indicated that the Ag nanoparticles can effectively promote the separation efficiency of photogenerated charge carriers on surface of g-C3N4-NS. Moreover, the localized surface plasmon resonance (SPR) of Ag nanoparticles also can improve the photocatalytic activity of Ag/g-C3N4-NS composites. Finally, a reasonable photocatalytic mechanism of Ag/g-C3N4-NS composites was also proposed based on the experimental results.