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

Patent metadata

Field	Value
Publication number	US-10441945-B2
Application number	US-201615382630-A
Country	US
Kind code	B2
Filing date	Dec 17, 2016
Priority date	Dec 17, 2015
Publication date	Oct 15, 2019
Grant date	Oct 15, 2019

Abstract

The invention discloses a composite material used for catalyzing and degrading nitrogen oxide and its preparation method and application thereof. The invention of the hollow g-C3N4 nanospheres/reduced graphene oxide composite-polymer carbonized nanofiber material is prepared as follow: 1) the preparation of silica nanospheres; 2) the preparation of hollow g-C3N4 nanospheres; 3) the preparation of graphene oxide; 4) the preparation of surface modified hollow g-C3N4 nanoparticles preparation; 5) the preparation of composites; 6) the preparation of composite-polymer carbon nanofiber material. The raw materials used in the process is low cost and easy to get; the operation of the invention is simple and convenient without the use of expensive equipment in the whole process; the composite has high adsorption efficiency of ppb level nitrogen oxide with good repeatability.

First claim

The invention claimed is:

1. 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.

2. The preparation method according to claim 1 , wherein:
the mass ratio of ammonia, ethanol, water, and ethyl silicate in step (1) is 1:18.7:3.2:1.8;
the mass percentage of the ammonia in step (1) is 22%˜25%;
the mass ratio of the ethyl silicate and the mixed liquid of ethyl silicate and octadecyltrimethoxysilane in step (1) is 1:1.5; and
the mass ratio of the ethyl silicate and octadecyltrimethoxysilane in the liquid mixture of the ethyl silicate and octadecyltrimethoxysilane in step (1) is 1:0.45.

3. The preparation method according to claim 1 , wherein:
the mass ratio of said silica nanospheres and cyanamide in step (2) is 1:5.

4. The preparation method according to claim 1 , wherein:
the ratio of graphite and concentrated sulfuric acid in step (3) is 1g: 23 mL;
the mass ratio of graphite and Potassium Permanganate in step (3) is 1:6; and
Potassium Permanganate is divided into two batches with the same mass in step (3).

5. The preparation method according to claim 1 , wherein:
the ratio of said hollow graphitic carbon nitride nanosphere and 3-aminopropyltriethoxysilane in step (4) is 1 g: 3 mL; and
the concentration of the hollow graphitic carbon nitride nanosphere in said suspension in step (4) is 1 mg/mL.

6. The preparation method according to claim 1 , wherein:
the mass ratio of said surface modified hollow graphitic carbon nitride nanospheres and the graphene oxide in step (5) is 1:0.1;
the concentration of surface modified hollow graphitic carbon nitride nanospheres in said suspension in step (5) is 1 mg/mL;
the concentration of graphene oxide in aqueous solution in step (5) is 0.1 mg/mL; and
the mass ratio of said graphene oxide and the hydrazine hydrate in step (5) is 1:1.

7. The preparation method according to claim 1 , wherein:
the mass ratio of the composite and the polymer in step (6) is 1:20;
said polymer in step (6) is selected from any one of PAN, polyvinyl alcohol and polyvinylpyrrolidone;
the mass percentage of the polymer in dimethylformamide in step (6) is 10%; and
the conditions of said electrostatic spinning in step (6) are as follows: negative voltage-9 kV, positive voltage 18 kV, speed 0.2 mm/min.

Assignees

• Univ Soochow

Inventors

• Lu Jianmei
• Chen Dongyun

Classifications

• B01D53/56

  Nitrogen oxides (B01D53/60 takes precedence) · CPC title

• B01J2231/005

  General concepts, e.g. reviews, relating to methods of using catalyst systems, the concept being defined by a common method or theory, e.g. microwave heating or multiple stereoselectivity · CPC title

• B01J37/04

  Mixing {(B01J37/0009, B01J37/0018 take precedence)} · CPC title

• B01J37/0018

  Addition of a binding agent or of material, later completely removed among others as result of heat treatment, leaching or washing,(e.g. forming of pores; protective layer, desintegrating by heat) · CPC title

• C01B21/0605

  Binary compounds of nitrogen with carbon · CPC title