Surface hydroxylation of graphitic carbon nitride: Enhanced visible light photocatalytic activity

To improve the photocatalytic activity of graphitic carbon nitride (g-C3N4), surface hydroxylation was employed as an efficient modification method. Characterizations were conducted to examine the formation of surface hydroxyl groups, including Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and diffuse-reflection spectroscopy (DRS). The improvement of photocatalytic activity brought by the surface hydroxylation modification was examined by measuring the degradation of Rhodamine B under visible light irradiation. Both theoretical and experimental explanations were given concerning the formation of photo-generated active radicals. This study sheds light on the benefits of surface hydroxylation modification, as well as on the differences in the roles of active radical species.