Preparation Of Carbon Nitride-based Visible-light Photocatalysts And Their Efficient Photocatalytic Performance

As a metal-free visible-light semiconductor photocatalyst,graphitic carbon nitride（g-C₃N₄）has attracted much attention in the field of environmental photocatalysis because of its advantages,such as low-cost,environment-friendly,and visible-light response.However,bulk layered structure leads to the poor visible-light photocatalytic activity of g-C₃N₄,which severely limits the practical application of g-C₃N₄ in the field of environmental photocatalysis.On the one hand,bulk layered structure is not conducive to the migration of photogenerated carriers to the surface of g-C₃N₄.On the other hand,bulk layered structure is not conducive to the contact of g-C₃N₄ with target molecules.In order to solve the above problems,sponge-like carbon nitride,molecularly imprinted carbon nitride,and small size carbon nitride with excellent visible-light photocatalytic activity were fabricated by precursor pretreatment method,sol-gel method,and one-step hydrothermal cutting method in this paper.The morphology,textural property,phase structure,chemical structure,light absorption property,and quantum efficiency of as-prepared materials were characterized by field emission scanning electron microscopy,transmission electron microscopy,nitrogen gas porosimetry measurements,X-ray diffraction spectroscopy,fourier transform infrared spectra,UV–vis/diffuse reflectance spectroscopy,and fluorescence spectrophotometer.Finally,the visible-light photocatalytic activity of as-prepared materials was evaluated by the degradation of typical aqueous organic pollutants rhodamine B,methyl orange,p-nitrophenol,p-fluorophenol,and p-chlorophenol.