▎ 摘　　要

NOVELTY - Preparing graphene/tungsten trioxide/silver composite photocatalytic film involves: (1) preparing graphene film; (2) preparing tungsten trioxide nanopowder; (3) preparing graphene/tungsten trioxide film; and (4) preparing graphene/tungsten trioxide/silver composite photocatalytic film by spraying an appropriate amount of binder on the surface of the indium tin oxide conductive glass with the graphene/tungsten trioxide film obtained in step (3), then using it as an anode electrode and taking a certain mass of silver target as a cathode, parallelly placing in argon gas and applying a direct current voltage of 200-400 V between the two plates for 0.5-2 hours to obtain a graphene/tungsten trioxide/silver film attached to the anode, horizontally placing the indium tin oxide conductive glass with the graphene/tungsten trioxide/silver film, spraying a small amount of absolute ethanol on the surface of the film, drying and then calcining. USE - The method is useful for preparing graphene/tungsten trioxide/silver composite photocatalytic film. ADVANTAGE - The method does not need to separate and recover the powder, and the prepared film is more convenient to use. DETAILED DESCRIPTION - Preparing graphene/tungsten trioxide/silver composite photocatalytic film involves: (1) preparing graphene film by (a) putting a copper foil with a thickness of 25 mu m into a quartz tube, vacuumizing, introducing hydrogen for 5 minutes to exhaust air, then heating at 1000 degrees C and maintaining the hydrogen flow rate at 2-6 sccm and the gas pressure constant at 40 mTorr for a period of time, (b) after the temperature and pressure are stabilized, introducing 35-40 sccm methane and maintaining the total pressure at 500 mTorr for a period of time, (c) after a period of deposition, stopping methane, heating and cooling at a cooling rate of 50 degrees C/hour to room temperature to form a graphene film on the copper foil and (d) spin-coating a suitable amount of 0.01 mol/l polymethylmethacrylate (PMMA) solution on the surface of the graphene film, then placing the copper foil in a ferric chloride solution, after 12-15 hours, removing PMMA/graphene film from the ferric chloride solution and transferring to indium tin oxide conductive glass, then spin-coating a certain amount of 0.01 mol/l PMMA and placing in an appropriate amount of acetone for 5-8 hours; (2) preparing tungsten trioxide nanopowder by (a) adding a certain amount of ammonium metatungstate (AMT) to an appropriate amount of distilled water, continuously stirring to completely dissolve the solid to obtain a solution (A), adding polyacrylic acid (PAA) and methylenebisacrylamide (MBA) to the solution (A), magnetically stirring for a period of time to make the components evenly distributed in the solution, leaving still at 80-100 degrees C for 3.5 hours and then naturally cooling for 1.5-2 hours to obtain a precursor sol (A), and (b) drying the precursor sol (A) in a drying oven, grinding to obtain a AMT dry gel powder, followed by pulverizing into fine powder by ultrasonic waves of a certain frequency and carrying out vacuum annealing treatment on the pulverized mixture in a vacuum annealing furnace for a period of time and cooling for 2-3 hours; (3) preparing graphene/tungsten trioxide film by (a) adding the tungsten trioxide nanopowder prepared in step (2) to a certain amount of isobutanol and stirring for 20-30 minutes to uniformly distribute the powder in the solvent to obtain a sol (B) and (b) uniformly spin-coating the sol (B) on the graphene-attached indium tin oxide conductive glass obtained in step (1) and drying for a period of time; and (4) preparing graphene/tungsten trioxide/silver composite photocatalytic film by spraying an appropriate amount of binder on the surface of the indium tin oxide conductive glass with the graphene/tungsten trioxide film obtained in step (3), then using it as an anode electrode and taking a certain mass of silver target to serve as a cathode, parallelly placing the anode and cathode in argon gas and applying a direct current voltage of 200-400 V between the two plates for 0.5-2 hours to obtain a graphene/tungsten trioxide/silver film attached to the anode, horizontally placing the indium tin oxide conductive glass with the graphene/tungsten trioxide/silver film, spraying a small amount of absolute ethanol on the surface of the film, drying and then calcining. The quartz tube has an inner diameter of 25 mm and a length of 1.5 m. In step (2): the relative molecular mass of the PAA is 6000-8000; and the volume ratio of the solution (A), PAA and MBA is 100:20:3. In step (2), the precursor sol (A) is dried at 200-300 degrees C for 8-10 hours. In the annealing treatment, the oxygen partial pressure is 10 Pa, the annealing temperature is 600 degrees C, and the heating rate is 60 degrees C/hour. In step (3), the drying step is carried out at 30 degrees C for 18-24 hours. In step (4), the calcining step is carried out at 450-500 degrees C for 6-10 hours.