▎ 摘　　要

NOVELTY - A metal foam-graphene composite substrate photocatalytic film comprises metal foam-graphene composite substrate coated from the inside to the outside with gallium-containing derivative (I) as buffer layer and n-type buffer layer, p-type graphitic carbon nitride (g-C3N4) layer, and noble metal nanoparticle layer. USE - Metal foam-graphene composite substrate photocatalytic film used for photodecomposition of water to prepare hydrogen, degrading organic pollutant in wastewater to remove harmful gas, and purifying air. ADVANTAGE - The photocatalytic film has good visible light photocatalytic effect. DETAILED DESCRIPTION - A metal foam-graphene composite substrate photocatalytic film comprises metal foam-graphene composite substrate coated from the inside to the outside with gallium-containing derivative of formula GaxZn1-xNxO1-x (I) as buffer layer and n-type buffer layer, p-type graphitic carbon nitride (g-C3N4) layer, and noble metal nanoparticle layer. x=0.1-0.7. An INDEPENDENT CLAIM is included for preparation of the photocatalytic film comprising: (A) adding metal foam-graphene composite substrate to loading chamber of electron cyclotron resonance plasma enhanced metalorganic chemical vapor deposition (ECR-PEMOCVD) device, transferring to vacuum reaction chamber, vacuumizing at 5\10-4 Pa to 1x 10-5 Pa, heating from room temperature to 400 degrees C while feeding nitrogen gas at flow rate of 60-150 standard cm3 (sccm) until vacuum chamber pressure reaches 0.5-3 Pa, and performing nitrogen plasma nitriding at microwave power of 300-800 W for 1-5 minutes; (B) heating from room temperature to 500 degrees C while feeding nitrogen gas and mixed gas of ammonia and oxygen at nitrogen gas flow rate of 0-145 sccm, ammonia gas flow rate of 0-145 sccm, oxygen gas flow rate of 5-30 sccm and at mixed gas of ammonia and oxygen total flow rate of 60-150 sccm until vacuum chamber pressure reaches 0.5-3 Pa, performing microwave treatment at 300-1000 W, feeding trimethyl gallium (TMGa) at molar flow rate of 1-7x 10-6 mol/minute and diethyl zinc (DEZn) at molar flow rate of 3-9x 10-6 mol/minute, and reacting to obtain buffer layer; (C) heating to 300-600 degrees C while feeding nitrogen gas and mixed gas of ammonia and oxygen at nitrogen gas flow rate of 0-145 sccm, ammonia gas flow rate of 0-145 sccm, oxygen gas flow rate of 5-30 sccm and at mixed gas of ammonia and oxygen total flow rate of 60-150 sccm until vacuum chamber pressure reaches 0.5-3 Pa, performing microwave treatment at 300-1000 W, feeding TMGa at molar flow rate of 1-7x 10-6 mol/minute, DEZ at molar flow rate of 3-9x 10-6 mol/minute and dopant silane at concentration of 3x 1017/cm3 to 3x 1019/cm3, and reacting to obtain n-type buffer layer; (D) adding dopant borane ammonia powder to urea powder, stirring to obtain borane ammonia-urea dopant system powder, controlling borane ammonia content to 0.5-5%, depositing to n-type buffer layer, placing to crucible, covering, putting to muffle furnace, heating to 525-590 degrees C at heating rate of 5-20 degrees C/minute for 2-4 hours to carry out thermal polymerization under nitrogen atmosphere to obtain p-type g-C3N4, and naturally cooling to room temperature; and (E) placing to coating room, pressurizing at 1-5x 10-4 Pa, purging with argon gas at flow rate of 40-200 sccm until coating chamber pressure reaches 0.15 Pa, setting radio frequency sputtering power supply to 30-100 W, radio frequency magnetron sputtering p-type g-C3N4 layer with precious metal as target, and controlling average particle size to 2-50 nm.