Enhanced visible light photocatalytic degradation of Rhodamine B over phosphorus doped graphitic carbon nitride.

Phosphorus doped graphitic carbon nitride (g-C 3 N 4 ) was easily synthesized using ammonium hexafluorophosphate (NH 4 PF 6 ) as phosphorus source, and ammonium thiocyanate (NH 4 SCN) as g-C 3 N 4 precursor, through a direct thermal co-polycondensation procedure. The obtained phosphorus doped g-C 3 N 4 was characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectra (FTIR), UV–vis diffuse reflectance absorption spectra (UV-DRS), photoelectrochemical measurement and photoluminescence spectra (PL). The photocatalytic activities of phosphorus doped g-C 3 N 4 samples were evaluated by degradation of Rhodamine B (RhB) solution under visible light irradiation. The results showed that the phosphorus doped g-C 3 N 4 had a superior photocatalytic activity than that of pristine g-C 3 N 4 , attributing to the phosphorus atoms substituting carbon atoms of g-C 3 N 4 frameworks to result in light harvesting enhancement and delocalized π-conjugated system of this copolymer, beneficial for the increase of photocatalytic performance. The photoelectrochemical measurements also verified that the charge carrier separation efficiency was promoted by phosphorus doping g-C 3 N 4 . Moreover, the tests of radical scavengers demonstrated that the holes (h + ) and superoxide radicals ( O 2 − ) were the main active species for the degradation of RhB. [ABSTRACT FROM AUTHOR]