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CN-121972194-A - Carbon nitride composite material and preparation method and application thereof

CN121972194ACN 121972194 ACN121972194 ACN 121972194ACN-121972194-A

Abstract

The invention discloses a carbon nitride composite material, a preparation method and application thereof, which are designed and prepared to be an activated carbon loaded modified carbon nitride nano sheet, K ions are doped between modified carbon nitride nano sheet layers to form KN bridging, local geometric distortion caused by K + intercalation is cooperated with P gap state, and the adsorption and activation capacity of the material to O 2 molecules are optimized together, so that the proceeding of OO-OOH reaction is accelerated remarkably. The adsorption enrichment function of the activated carbon and the oxidative degradation and sterilization capacities of the photocatalytic material can be fully utilized.

Inventors

  • ZHAO HUANYU
  • PAN WENYUAN
  • ZHANG QICHANG

Assignees

  • 北京科技大学

Dates

Publication Date
20260505
Application Date
20251201

Claims (7)

  1. 1. The carbon nitride composite material is characterized in that the carbon nitride composite material is an activated carbon loaded modified carbon nitride nano sheet, the modified carbon nitride nano sheet comprises a structural unit 1, and the structural unit 1 is: wherein A and B are independently structural units 1 or C3N4, and K ions are doped between the modified carbon nitride nano-sheets to form KN bridging.
  2. 2. The method for preparing the carbon nitride composite material according to claim 1, wherein melamine, dipotassium dihydrogen pyrophosphate and potassium dihydrogen phosphate are mixed with porous activated carbon, and the mixture is calcined at a high temperature of 550-650 ℃ for 4 hours in an inert atmosphere, cooled, washed and dried to obtain the carbon nitride composite material; wherein the mass ratio of melamine to dipotassium dihydrogen pyrophosphate to monopotassium phosphate to porous activated carbon is 100 (5-25)/(10-30)/(50-200).
  3. 3. The method of claim 2, wherein the high temperature calcination is at a ramp rate of 2 ℃ per minute.
  4. 4. The method of claim 2, wherein the drying is performed at 80 ℃ for 12 hours.
  5. 5. The method according to claim 2, characterized in that the mass ratio of melamine, dipotassium dihydrogen pyrophosphate, potassium dihydrogen phosphate to porous activated carbon is 1:1.
  6. 6. Use of the carbon nitride composite material according to claim 1 in photocatalysis.
  7. 7. The use according to claim 6, for photocatalytic degradation of volatile organic compounds, which are nitrogen oxides, sulphur oxides.

Description

Carbon nitride composite material and preparation method and application thereof Technical Field The invention belongs to the technical field of environmental functional materials, and particularly relates to a carbon nitride composite material and a preparation method and application thereof. Background With the acceleration of industrialization and urbanization, indoor and outdoor air pollution problems are increasingly serious. The pollutants in the air mainly comprise microbial pollutants such as bacteria and viruses, and chemical pollutants such as Volatile Organic Compounds (VOCs), nitrogen oxides (NO x), sulfur oxides (SO x) and the like. The traditional air purification technology, such as activated carbon adsorption, mainly relies on physical adsorption, and has the problems of high saturation speed, incapability of decomposing pollutants, easiness in becoming a secondary pollution source and the like. Ultraviolet lamp sterilization is ineffective against chemical contaminants such as VOCs and may produce ozone by-products. Photocatalytic technology is considered as an ideal air purification solution that can directly degrade various organic pollutants and inactivate microorganisms using light energy. Among the many photocatalytic materials, polymeric carbon nitride (g-C 3N4) has received much attention for its advantages of non-toxicity, stability, visible light response, and the like. However, the original gC 3N4 has inherent defects of low photo-generated carrier separation efficiency, small specific surface area, slow surface reaction kinetics and the like, which results in low photo-catalytic purification efficiency. Although activated carbon has a high specific surface area and excellent adsorption performance, it is widely used as an adsorbent, but it can only enrich contaminants rather than degrade, is susceptible to saturation failure, and may become a hotbed for microorganism growth. Disclosure of Invention Aiming at the problem that the photocatalytic material in the prior art is difficult to have high specific surface area and high catalytic performance at the same time, the application provides a carbon nitride composite material, a preparation method and application thereof, and designs and prepares a modified carbon nitride nano sheet loaded by active carbon, K ions are doped between modified carbon nitride nano sheet layers to form KN bridging, local geometric distortion caused by K + intercalation is generated in cooperation with P gap state, and the adsorption and activation capacity of the material to O 2 molecules are optimized together, so that the performance of OO-OOH reaction is remarkably accelerated. The adsorption enrichment function of the activated carbon and the oxidative degradation and sterilization capacities of the photocatalytic material can be fully utilized. The carbon nitride composite material is an activated carbon loaded modified carbon nitride nano sheet, the modified carbon nitride nano sheet comprises a structural unit 1, and the structural unit 1 is as follows: wherein A and B are independently structural units 1 or C 3N4, and K ions are doped between the modified carbon nitride nano-sheet layers to form KN bridging. The thickness of the modified carbon nitride nano-sheet is not more than 50nm. The invention also provides a preparation method of the carbon nitride composite material, which comprises the steps of mixing melamine, dipotassium dihydrogen pyrophosphate, potassium dihydrogen phosphate and porous activated carbon, placing the mixed material in a crucible with a cover, wrapping the crucible with aluminum foil, calcining at a high temperature of 550-650 ℃ for 4 hours in an inert atmosphere, cooling, and repeatedly washing and drying by ultrapure water, wherein the mass ratio of the melamine to the dipotassium dihydrogen pyrophosphate to the potassium dihydrogen phosphate to the porous activated carbon is 100 (5-25) (10-30) (50-200). Further, the temperature rising rate of the high-temperature calcination is 2 ℃ per minute. At moderate ramp rates, KH 2PO4 thermally decomposes to release active phosphorus species with strong electrophilicity. These species preferentially attack the nitrogen-rich sites at the heptazine ring edge, inducing deprotonation of the terminal amino group (-NH 2) at the beginning of thermal polymerization, leading to the targeted formation of the critical cyano functionality (-c≡n). The cyano group formed in situ rapidly initiates redistribution of electron density in the heptazine ring due to the strong electron withdrawing effect, obviously reduces electron cloud density of the C 3 site, and creates unique thermodynamic advantage for accurate substitution of the subsequent P-OH group on the site. In addition, the cyano group is not only helpful to promote the effective separation of photo-generated charges, but also the unique pi orbit of the cyano group can be effectively coupled with a reaction intermediate OOH, so that