▎ 摘　　要

NOVELTY - Graphene-enhanced photocatalytic gradient composite organic film comprises multiple photocatalytic layers, each adjacent two photocatalytic layers are separately prepared with an intermediate enhancement layer, the middle reinforcement layer is composed of graphene/polyvinyl alcohol organic composite film material layer, the graphene in the graphene/polyvinyl alcohol organic composite film material layer is graphene modified by polyvinylpyrrolidone, each photocatalytic layer is composed of indium sulfide/polyvinyl alcohol organic composite film material layer or indium zinc sulfide/polyvinyl alcohol organic composite film material layer and the middle enhancement layer realizes the electron migration and mechanical strength enhancement. USE - Used as graphene-enhanced photocatalytic gradient composite organic film. ADVANTAGE - The film: has high-efficiency catalytic ability; improves the mechanical strength of the composite organic membrane; solves the recovery problem and service life of the photocatalyst in practical applications; reduces the environmental hazards of persistent organic pollutants; has many advantages e.g. high mechanical properties, good photocatalytic efficiency, easy recycling and reuse. DETAILED DESCRIPTION - AN INDEPENDENT CLAIM are also included for preparing graphene-enhanced photocatalytic gradient composite organic film comprising (1) modifying the graphene by polyvinylpyrrolidone to obtain modified graphene, mixing polyvinyl alcohol, water, and modified graphene to obtain a graphene/polyvinyl alcohol mixed solution, which is used to prepare the intermediate reinforcement layer, (2) taking indium source or indium zinc source and polyvinyl alcohol as raw materials, adding it to water to obtain a mixed solution of indium source or indium zinc source and polyvinyl alcohol, adding sulfur source solution to the indium source or the mixed solution of indium zinc source and polyvinyl alcohol, preparing a mixed solution of indium sulfide/polyvinyl alcohol or a mixed solution of indium zinc sulfide/polyvinyl alcohol for use in preparing the photocatalytic layer, (3) coating a layer of the indium sulfide/polyvinyl alcohol mixed solution or indium zinc sulfide/polyvinyl alcohol mixed solution, making it flat, freezing at -23 to -27 degrees C for 8-12 hours and thawing at 24-26 degrees C for 6-8 hours to obtain the indium sulfide/polyvinyl alcohol organic composite film material layer or the indium zinc sulfide/polyvinyl alcohol organic composite film material layer as the lowermost photocatalytic layer, (4) coating a layer of the graphene/polyvinyl alcohol mixed solution on the lowermost photocatalytic layer, keeping it flat, freezing at -23 to -27 degrees C for 8-12 hours, thawing at 24-26 degrees C for 6-8 hours and preparing a graphene/polyvinyl alcohol organic composite film material layer on the lowermost photocatalytic layer as an intermediate enhancement layer, (5) coating the intermediate strengthening layer again with a layer of indium sulfide/polyvinyl alcohol mixed solution or indium zinc sulfide/polyvinyl alcohol mixed solution, keeping it flat, freezing at -23 to -27 degrees C for 8-12 hours, thawing at 24-26 degrees C for 6-8 hours and preparing a layer of indium sulfide/polyvinyl alcohol organic composite film material layer or indium zinc sulfide/polyvinyl alcohol organic composite film material layer as a photocatalytic layer on the middle reinforcing layer and (6) cleaning the product until the pH value of the cleaning solution is neutral, drying to a constant weight to obtain a three-layer structure photocatalytic gradient composite organic film, where if a photocatalytic gradient composite organic film with an odd-numbered layer structure with more than 3 layers is required, repeating the above steps (4) and (5) for the corresponding number of times, washing obtained product until the pH value of the cleaning solution is neutral, and drying to a constant weight to obtain a photocatalytic gradient composite organic film with the corresponding number of layers. DESCRIPTION OF DRAWING(S) - The drawing shows a schematic representation of the graphene-enhanced photocatalytic gradient composite organic film.