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CN-121990562-A - Three-dimensional structure graphene material loaded with phosphorus-doped carbon nitride quantum dots, and preparation method and application thereof

CN121990562ACN 121990562 ACN121990562 ACN 121990562ACN-121990562-A

Abstract

The invention belongs to the field of carbon-based electrode materials, and discloses a three-dimensional structure graphene material loaded with phosphorus-doped carbon nitride quantum dots, and a preparation method and application thereof. The three-dimensional structure graphene material is prepared by simple hydrothermal reaction, wherein phosphorus-doped carbon nitride quantum dots are uniformly dispersed on graphene sheets, and nitrogen and phosphorus elements are successfully introduced into graphene due to in-situ loading of the phosphorus-doped carbon nitride quantum dots. The three-dimensional structure graphene material prepared by the method has a good self-supporting three-dimensional skeleton structure, can be directly used for preparing an electrode under the condition of no addition of a conductive agent and a binder, has excellent electrochemical performance when being used as an electrode, and has wide application prospect in the fields of electrode materials and energy storage devices.

Inventors

  • WU JIAOJIAO
  • XU XIANGYA
  • JIN QIUYAN
  • LI WEI

Assignees

  • 中国石油化工股份有限公司
  • 中石化(北京)化工研究院有限公司

Dates

Publication Date
20260508
Application Date
20241107

Claims (11)

  1. 1. A three-dimensional structure graphene material loaded with phosphorus-doped carbon nitride quantum dots comprises graphene and phosphorus-doped carbon nitride quantum dots loaded on the graphene.
  2. 2. The three-dimensional structure graphene material loaded with phosphorus-doped carbon nitride quantum dots according to claim 1, wherein, In the three-dimensional structure graphene material of the phosphorus-loaded doped carbon nitride quantum dot, the content of nitrogen atoms is 1-20 atom percent, preferably 2-10 atom percent, and the content of phosphorus atoms is 0.01-1 atom percent, preferably 0.02-0.5 atom percent in terms of atomic percent.
  3. 3. A method for preparing the three-dimensional structure graphene material loaded with the phosphorus-doped carbon nitride quantum dots according to any one of claims 1-2, comprising the step of loading the phosphorus-doped carbon nitride quantum dots on graphene to form the three-dimensional structure graphene material.
  4. 4. A method of preparation according to claim 3, comprising the specific steps of: (1) Adding a nitrogen-containing carbon source and an organic acid compound into a phosphorus source solution, and obtaining a phosphorus-doped carbon nitride quantum dot dispersion liquid through a first hydrothermal reaction; (2) Dropwise adding the aqueous dispersion liquid containing the phosphorus-doped carbon nitride quantum dots into the graphene oxide suspension liquid, and mixing and stirring to obtain a uniform mixed suspension liquid; (3) And (3) performing a second hydrothermal reaction on the mixed suspension liquid obtained in the step (2), and washing and drying to obtain the three-dimensional structure graphene material loaded with the phosphorus-doped carbon nitride quantum dots.
  5. 5. The method according to claim 4, wherein, The nitrogen-containing carbon source is selected from at least one of organic amine compounds, preferably at least one of urea, thiourea and melamine, and/or, The organic acid compound is selected from at least one of polybasic fatty acid compounds, preferably at least one of polybasic fatty acid compounds of C2-C8, more preferably at least one of citric acid, malic acid and oxalic acid, and/or, The phosphorus source in the phosphorus source solution is at least one selected from organic or inorganic phosphoric acid compounds, preferably at least one selected from phytic acid, phosphoric acid and phosphorous acid.
  6. 6. The method according to claim 4, wherein in the step (1): The molar ratio of the organic acid compound to the nitrogen-containing carbon source is 1 (1-50), preferably 1 (1-10), and/or, The mole ratio of the phosphorus source to the nitrogen-containing carbon source in the phosphorus source solution is 1 (10-1000), preferably 1 (100-500), and/or, The concentration of the phosphorus source in the phosphorus source solution is 1-50 mg/mL, preferably 1-10 mg/mL, and/or, The first hydrothermal reaction condition is that the reaction temperature is 120-200 ℃ and/or the reaction time is 3-24 h.
  7. 7. The method according to claim 4, wherein in the step (2): in the aqueous dispersion of the phosphorus-containing doped carbon nitride quantum dots, the concentration of the phosphorus-containing doped carbon nitride quantum dots is 0.1-10 mg/mL, preferably 1-5 mg/mL, and/or, In the graphene oxide suspension, the concentration of graphene oxide is 0.1-10 mg/mL, preferably 1-5 mg/mL, and/or, The mass ratio of the phosphorus doped carbon nitride quantum dots to the graphene oxide is 1 (1-100), preferably 1 (5-20), and/or, The mixing and stirring mode is that mechanical stirring is carried out for 0.5-2 hours, and ultrasonic mixing is carried out for 0.5-2 hours.
  8. 8. The method according to claim 4, wherein in the step (3): The second hydrothermal reaction is carried out under the conditions that the reaction temperature is 120-200 ℃ and/or the reaction time is 6-24 h and/or, The drying mode is freeze drying.
  9. 9. In the three-dimensional structure graphene material loaded with the phosphorus-doped carbon nitride quantum dots obtained by the preparation method according to any one of claims 3-8, preferably, the graphene sheets form a self-supporting skeleton structure, and the phosphorus-doped carbon nitride quantum dots are uniformly distributed on the graphene sheets.
  10. 10. The three-dimensional structure graphene material loaded with phosphorus-doped carbon nitride quantum dots according to claim 9, wherein, In the three-dimensional structure graphene material of the phosphorus-loaded doped carbon nitride quantum dot, nitrogen elements exist in the forms of pyridine nitrogen, pyrrole nitrogen and graphite nitrogen and mainly comprise pyrrole nitrogen, and/or, The size of the phosphorus-doped carbon nitride quantum dot is 1-20 nm, preferably 2-10 nm.
  11. 11. The application of the three-dimensional structure graphene material loaded with the phosphorus-doped carbon nitride quantum dots according to any one of claims 1-2 and 9-10 in an electrode material or a supercapacitor.

Description

Three-dimensional structure graphene material loaded with phosphorus-doped carbon nitride quantum dots, and preparation method and application thereof Technical Field The invention belongs to the field of carbon-based electrode materials, and particularly relates to a three-dimensional structure graphene material loaded with phosphorus-doped carbon nitride quantum dots, and a preparation method and application thereof. Background The super capacitor has high power density and excellent cycle stability because of rapid charge and discharge, and has gained wide attention. Supercapacitors are classified into two types, an electric double layer capacitor and a pseudocapacitance capacitor, according to a charge storage mechanism. The electric double layer capacitor stores charges by means of reversible adsorption of ions on the surface of the electrode material, has the advantages of long cycle life, environmental friendliness and the like, and the commonly used electrode material is carbon-based material comprising activated carbon, carbon nanotubes, graphene and the like. Graphene, which is a material having a high electron transport rate and excellent stability, is a research hotspot in the field of carbon-based electrode materials. However, due to the effect of strong pi-pi bonds, stacking and agglomeration are easy to occur between the flaky graphene layers, which is not beneficial to electrolyte passing when the flaky graphene is applied to electrode materials, and therefore, the capacitance performance is not ideal. In recent years, researchers modify flaky graphene by introducing phosphorus, nitrogen elements and the like to increase structural defects and conductivity of graphene and improve performance of graphene-based capacitors. However, the existing method still has the problems of complex synthetic route and the like. In addition, when preparing electrodes using graphene flakes, it is generally necessary to prepare a slurry of the material using a binder, and then apply the slurry to the electrode substrate, and the presence of the binder adversely affects the conductivity of the electrode. Carbon nitride is a graphite-like two-dimensional layered semiconductor material rich in carbon and nitrogen elements, and the introduction of carbon nitride into a graphene electrode material system can introduce nitrogen elements into graphene, so that pseudocapacitance is increased, and the method is an optional mode for improving the performance of a capacitor. However, bulk carbon nitride prepared by conventional direct pyrolysis of nitrogen-rich precursors has poor conductivity, and the conductivity of an electrode can be affected after the bulk carbon nitride and graphene form a composite material. Disclosure of Invention The invention aims to solve the problems of non-ideal capacitance performance and complex preparation process of lamellar graphene, and provides a three-dimensional structure graphene material (PNQDs-3 DG) loaded with phosphorus-doped carbon nitride quantum dots, and a preparation method and application thereof. The load of the phosphorus-doped carbon nitride quantum dot (PNQDs) introduces a certain amount of phosphorus and nitrogen elements into graphene, and meanwhile, the conductivity of the graphene is not influenced, and the prepared PNQDs-3DG has a cross-linked three-dimensional structure. The super capacitor assembled by PNQDs-3DG does not need to add conductive agent and binder when the electrode is prepared, and has high specific capacitance and excellent stability. In order to achieve the above purpose, the present invention adopts the following technical scheme. The invention provides a three-dimensional structure graphene material loaded with phosphorus-doped carbon nitride quantum dots, which comprises graphene and phosphorus-doped carbon nitride quantum dots loaded on the graphene. According to the three-dimensional structure graphene material of the phosphorus-doped carbon nitride quantum dot, the content of nitrogen atoms is 1 to 20atom% (for example, 1,2,3,4,5,6,7,8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20atom% or a value between any two of the above numerical ranges), preferably 2 to 10atom%, and the content of phosphorus atoms is 0.01 to 1atom% (for example, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1atom% or a value between any two of the above numerical ranges), preferably 0.02 to 0.5atom%. The second aspect of the invention provides a preparation method of the three-dimensional structure graphene material loaded with the phosphorus-doped carbon nitride quantum dots, which comprises the step of loading the phosphorus-doped carbon nitride quantum dots on graphene to form the three-dimensional structure graphene material. According to the invention, the preparation method of the three-dimensional structure graphene material loaded with the phosphorus-doped carbon nitride quantum dots specifically comprises