The invention provides a photocatalytic
composite material with p-n
heterojunction, and belongs to the field of organic
pollutant treatment. The narrow-band-gap photocatalytic
composite material withp-n
heterojunction disclosed by the invention improves deficiency of a single catalyst, has a small
band gap energy (1.87 eV), has a large absorption threshold on visible light, and has enhanced lightutilization efficiency. The p-n
heterojunction caused by bending of the energy band increases the hole
transfer ability, inhibits
electron-hole recombination, improves the separation efficiency of photogenerated electrons and holes, prolongs the
carrier lifetime and enhances the catalytic activity. Under visible light, the photocatalytic
composite material has good degradation effects on organicpollutants in water, such as MO, MG, BPA,
tetracycline hydrochloride, etc. At the same time, the narrow-band-gap photocatalytic composite material with p-n heterojunction disclosed by the invention can settle in water through standing, so that the narrow-band-gap photocatalytic composite material can be separated from an
aqueous solution, and thus the narrow-band-gap photocatalytic composite material is beneficial to
recovery and reuse of materials, has good regenerative capacity and can be recycled.