Sulfur doping and structure defect functionalized carbon nitride nanosheets with enhanced photocatalytic degradation activity

Abstract Carbon nitride (C3N4) is a promising semiconductor photocatalytic material to treat residual pollutants in water. However, the limited visible light absorption and severe recombination of photoinduced carriers restrict the further development of C3N4 photocatalyst. Herein, sulfur doping and structure defect simultaneous functionalized C3N4 nanosheets (SCN-T) were prepared by convenient copolymerization of dicyandiamide and thioacetamide followed by thermal oxidation etching process. The SCN-T can not only harvest more visible light due to sulfur doping by lifting the valence band and conduction band, but also exhibit stronger reduction ability originated from combined effect of doping and exfoliation, higher separation and transfer efficiency and prolonged average lifetime of photoinduced carriers than pristine bulk C3N4 because of defect and sheet structures. The photocatalytic activity of the SCN-T was evaluated by performing the degradation experiments of Rhodamine B (RhB) and tetracycline hydrochloride (TC-HCl), and the results show that SCN-T exhibits a significant enhanced photocatalytic degradation activity. The degradation rate constants for RhB and TC-HCl over the SCN-T are 4.95 times and 2.07 times that of pristine bulk C3N4, respectively. The work provides valuable information for the activity optimization on the basis of composition and structural properties.