Composite material used for catalyzing and degrading nitrogen oxide and preparation method and application thereof

A preparation method of a hollow graphitic carbon nitride nanosphere/graphene composite and composite-carbonized polymer nano fiber material, comprising the following steps:

• (1) preparation of silica nanospheres:
• adding ethyl silicate into a mixture of ammonia, ethanol and water having a mass ratio of ammonia:
• ethanol:
• water:
• ethyl silicate=1:15˜20:1˜5:1˜2, the formed mixture standing for 1˜2 hours, adding a mixture of ethyl silicate and octadecyltrimethoxysilane having a mass ratio of ethyl silicate:
• octadecyltrimethoxysilane=1:1-2 to previously formed the mixture, mixing evenly and standing for 3˜5 hours, a resulted mixture being centrifugated, dried and calcined for 6˜8 hours at 55˜570° C., and then washed with 1M hydrochloric acid and dried, to obtain the silica nanospheres,
• (2) preparation of hollow graphitic carbon nitride nanospheres:
• using the silica nanospheres in the step (1) as a template and mixing with cyanamide in a mass ratio of 1:3˜7 and stirring for 3˜5 hours under vacuum, ultrasonic treating for 2˜3 hours, and then reacting at 60˜70° C. for 10˜12 hours and obtaining a solid by centrifugation, the obtained solid being heated to 55˜570° C. under inert gas atmosphere and calcined for 4˜5 hours producing a powder, then using 4M ammonium acid fluoride to etch the silica nanospheres template in the powder, after centrifuging, washing and drying, obtaining the hollow graphitic carbon nitride nanospheres,
• (3) preparation of graphene oxide:
• adding graphite to concentrated sulfuric acid in a ratio of graphite:
• concentrated sulfuric acid=1g:
• 20˜25mL with stirring in an ice water bath, after mixing evenly, adding potassium hypermanganate to the mixture of graphite and concentrated sulfuric acid in a mass ratio of graphite:
• potassium hypermanganate=1:5˜8, reacting at 35˜40° C. for 12h pouring the mixture of graphite, concentrated sulfuric acid, and potassium hypermanganate into ice water containing hydrogen peroxide, after centrifugation, washing and drying, obtaining the graphene oxide,
• (4) preparation of surface modified hollow graphitic carbon nitride nanospheres:
• adding 3-aminopropyltriethoxysilane to a suspension of the hollow graphitic carbon nitride nanospheres in methylbenzene in a mass ratio of the hollow graphitic carbon nitride nanospheres:
• 3-aminopropyltriethoxysilane=1g:
• 3˜5mL, after refluxing for 20˜24 hours, centrifuging, washing and drying, obtaining the surface modified hollow graphitic carbon nitride nanospheres,
• (5) preparation of hollow graphitic carbon nitride nanospheres/graphene composite:
• adding graphene oxide aqueous solution to the surface modified hollow graphitic carbon nitride nanospheres in step (4) dispersed in water with a pH value of 10 in a mass ratio of the surface modified hollow graphitic carbon nitride nanospheres:
• graphene oxide=1:0.1˜0.3, stirring the mixture of the surface modified hollow graphitic carbon nitride nanospheres and the graphene oxide at room temperature for 1˜2 hours, adding hydrazine hydrate into the mixture in a mass ratio of graphene oxide:
• hydrazine hydrate=1:1˜2, reacting for 1˜2 hours at 95° C., centrifuging, washing and drying, obtaining the hollow graphitic carbon nitride nanospheres/graphene composite,
• (6) preparation of composite-carbonized polymer nanofiber material:
• adding the composite obtained in step (5) to a DMF solution of a polymer with a mass ratio of composite:
• polymer=1:15˜20, stirring the mixture of the composite and polymer at room temperature for 5˜8 hours, preparing a nanofiber through electrostatic spinning, the nanofiber being heated to 500˜520° C. under inert gas atmosphere and calcined for 4˜5 hours, obtaining the composite-carbonized polymer nanofiber material.