▎ 摘　　要

NOVELTY - Preparation of composite photocatalyst involves adding a dilute nitric acid solution of silver nitrate to an ammonium metavanadate aqueous solution, magnetically stirring, adjusting pH to 2-4 to obtain silver vanadium oxide solution, mixing 33% methylamine, 57% hydroiodic acid and ethanol solution, stirring, evaporating under nitrogen atmosphere to obtain crystals, washing the crystals, vacuum-drying to obtain methylammonium iodide crystals, dispersing aminated graphene in dimethylformamide, adding melamine, 4,4'-diaminodiphenyl ether and pyromellitic dianhydride, ultrasonically dispersing, performing low-temperature solution copolymerization to obtain a graphene carrier precursor solution, dissolving lead(II) chloride and methylammonium iodide white crystals in dimethylformamide, adding the graphene carrier precursor solution, transferring obtained mixture into a PTFE reactor, adding silver vanadium oxide solution, heating, reacting (R), water-washing and drying. USE - Preparation of composite photocatalyst (claimed) used for degrading printing and dyeing wastewater. ADVANTAGE - The composite photocatalyst has high stability, and excellent absorption performance and photocatalytic performance, and effectively improves the surface structure of material. The methylammonium lead iodide and silver vanadium oxide contained in the composite photocatalyst are combined on the surface of the graphene to form heterojunction, which broadens the range of light energy utilization, and the matched energy band structure is conducive to the separation of photogenerated electrons and holes, such that the efficiency of photocatalytic degradation is improved. DETAILED DESCRIPTION - Preparation of composite photocatalyst involves preparing an ammonium metavanadate aqueous solution and a dilute nitric acid solution of silver nitrate, adding the dilute nitric acid solution of silver nitrate to the ammonium metavanadate aqueous solution, magnetically stirring for 3-4 hours under dark condition, uniformly mixing, adjusting pH to 2-4 to obtain silver vanadium oxide solution, uniformly mixing 33% methylamine, 57% hydroiodic acid and ethanol solution, stirring and evaporating for 50 minutes under nitrogen atmosphere to obtain crystals, washing the crystals with dimethyl ether 3 times, vacuum-drying at 60℃ to obtain methylammonium iodide crystals, dispersing aminated graphene in dimethylformamide, adding melamine, 4,4'-diaminodiphenyl ether and pyromellitic dianhydride, ultrasonically dispersing, performing low-temperature solution copolymerization under the protection of nitrogen to obtain a graphene carrier precursor solution, dissolving lead(II) chloride and methylammonium iodide white crystals in dimethylformamide at a molar ratio of 1:1-1:4, adding the graphene carrier precursor solution, transferring obtained mixture into a PTFE reactor, adding silver vanadium oxide solution, heating, reacting (R), water-washing and drying.