▎ 摘　　要

NOVELTY - Preparing metal oxide or graphene composite film comprises (i) mixing graphite, sodium nitrate and concentrated sulfuric acid, stirring to obtain first mixture, (ii) adding potassium permanganate to first mixture, stirring in an ice water bath, adding distilled water, stirring, adding hydrogen peroxide stirring, and reacting to obtain second mixture, (iii) washing second mixture with distilled water for 5-6 times to obtain graphene oxide slurry, (iv) placing metal piece in distilled water, ultrasonically processing, polishing by sand paper to obtain processed metal piece, (v) taking graphene oxide, adding distilled water, ultrasonically dispersing to obtain third mixture, (vi) placing processed metal piece in third mixture, reacting in oil bath, washing unreacted graphene oxide adsorbed on surface of metal sheet with distilled water and anhydrous ethanol, ultrasonically dispersing obtained metal piece in organic solvent and taking out metal piece to obtain metal oxide. USE - The film is useful for preparing photo-catalytic hydrogen (claimed), and preparing many kinds of base metal oxide or graphene composite films. ADVANTAGE - The method: directly forms a film; is simple; and has mild reaction conditions. DETAILED DESCRIPTION - Preparing metal oxide or graphene composite film comprises (i) mixing graphite, sodium nitrate and concentrated sulfuric acid, stirring for 30 minutes to obtain first mixture, (ii) adding potassium permanganate to resulting first mixture, stirring for 12 hours in an ice water bath, adding distilled water, stirring for 12 hours, adding hydrogen peroxide stirring for 24 hours, and reacting to obtain second mixture, (iii) washing the resulting second mixture with distilled water for 5-6 times to obtain graphene oxide slurry, (iv) placing metal piece in distilled water, ultrasonically processing for 5 minutes, polishing with sand paper to obtain processed metal piece, (v) taking graphene oxide slurry obtained in the step (iii), adding distilled water, ultrasonically dispersing to obtain third mixture, (vi) placing processed metal piece obtained in step (iv) in third mixture obtained in step (v), reacting in oil bath at 25 degrees C for 12 hours, washing unreacted graphene oxide adsorbed on surface of the metal sheet with distilled water and anhydrous ethanol, ultrasonically dispersing the obtained metal piece in an organic solvent for 5 minutes, and taking out metal piece to obtain metal oxide or reduced graphene oxide composite solution, (vii) placing the substrate into beaker, adding distilled water, dropwise adding metal oxide or reduced graphene oxide compound solution obtained in step (vi) to form a metal oxide/reduced graphene oxide film on surface water, using straw to slowly sucking out excess water until liquid level drops below substrate, placing the substrate loaded with metal oxide or reduced graphene oxide in an oven and drying.