In-situ hard template synthesis of mesoporous carbon/graphite carbon nitride (C/CN-T-x) composites with high photocatalytic activities under visible light irridation

Abstract Carbon/graphite carbon nitride (C/CN-T-x) hybrid composites with high photocatalytic activities under visible light irradiation were synthesized by an in-situ hard template method using the partially formaldehyde-modified dicyandiamide (PFMD) and tetraethyl orthosilicate (TEOS) as the precursors and template, respectively. The structures of the as-prepared composites were characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD), elemental analysis, nitrogen adsorption-desorption, scanning electron microscopy (SEM), transmission electron microscopy (TEM), photoluminescence (PL) spectroscopy, and X-ray photoelectron spectroscopy (XPS). The composite prepared under the optimal conditions exhibits the large surface area of 174 m2･g-1 and high photocatalytic activity for the degradation of methylene blue (MB) under visible light irradiation. The significant improvement in photocatalytic activity of the composite, as compared with the pure graphite carbon nitride (CN), is attributed to the large surface area, strong dye adsorption ability and enhanced separation efficiency of photogenerated electron-hole pairs.