CN111330620A - Intercalation type graphite-like carbon nitride composite material, preparation method and application thereof - Google Patents

Abstract

The invention provides a preparation method of an intercalation type graphitic carbon nitride composite material, comprising: mixing the alkali metal ion intercalated graphitic carbon nitride g-C3N5 with a transition metal salt, and stirring to obtain an intercalation type carbonitride Graphitic carbon nitride composites. The present application also provides an intercalation type graphitic carbon nitride composite material, which is composed of graphitic carbon nitride g-C3N5 and transition metal atoms intercalated in the graphitic carbon nitride g-C3N5. The intercalated graphitic carbon nitride composite material provided by this application has great application prospects in photoelectric catalysis, electrocatalysis, energy storage, composite materials, etc. The synthesis method is simple, the loading capacity is large, and it is easy for large-scale production.

Description

Intercalation type graphitic carbon nitride composite material, preparation method and application thereof

technical field

The invention relates to the technical field of novel composite materials, in particular to an intercalation type graphitic carbon nitride composite material, a preparation method and application thereof.

Background technique

Transition metal single atoms have the highest atom utilization and active specific area. However, the synthesis of transition metal single atoms is still difficult, such as the low yield and high cost of atomic layer deposition methods, and general strategies for large-scale synthesis also have certain challenges. .

Graphite-like carbon nitride (g-C3N5) is an important class of conjugated polymer semiconductors with excellent electronic band structure (band gap width of 1.76 eV), chemical stability and environmental friendliness, which make g- C3N5 has a wide range of applications, including visible light photocatalytic water splitting, photodegradation of organic pollutants, etc.

SUMMARY OF THE INVENTION

The technical problem solved by the present invention is to provide an intercalation type graphitic carbon nitride composite material and a preparation method thereof. The intercalation type graphitic carbon nitride composite material provided by the present application can be used as an excellent catalyst for the reaction of moisture analysis and oxygen middle.

In view of this, the present application provides a preparation method of an intercalated graphite-like carbon nitride composite material, comprising:

The graphite-like carbon nitride g-C3N5 intercalated with alkali metal ions is mixed with a transition metal salt and stirred to obtain an intercalated graphitic-like carbon nitride composite material.

Preferably, the preparation method of the alkali metal ion intercalated graphitic carbon nitride g-C3N5 is specifically:

After mixing the alkali metal bromide, 3-amino-1,2,4-triazole and water, evaporating and grinding to obtain mixed powder;

Primary calcination of the mixed powder to obtain the initial alkali metal ion intercalated graphitic carbon nitride g-C3N5;

The initial alkali metal ion intercalated graphitic carbon nitride g-C3N5 is calcined again to obtain the alkali metal ion intercalated graphitic carbon nitride g-C3N5.

Preferably, the temperature of the primary calcination is 500-600°C, and the temperature of the re-calcination is 400-500°C.

Preferably, the stirring temperature is 50-100° C., and the stirring time is 24-48 h.

Preferably, the transition metal salt is selected from ferric nitrate nonahydrate, cobalt nitrate hexahydrate, nickel nitrate hexahydrate, manganese sulfate monohydrate or iridium chloride trihydrate.

The present application also provides an intercalation type graphitic carbon nitride composite material, which is composed of graphitic carbon nitride g-C3N5 and transition metal atoms intercalated in the graphitic carbon nitride g-C3N5.

Preferably, the transition metal atoms are selected from nickel atoms, cobalt atoms, iron atoms, manganese atoms or iridium atoms.

The present application also provides the intercalation type graphitic carbon nitride-like composite material prepared by the preparation method or the application of the intercalation type graphitic carbon nitride-like composite material in the water desorption oxygen reaction.

The application provides a preparation method of an intercalated graphitic carbon nitride composite material, which is prepared by mixing alkali metal ion intercalated graphitic carbon nitride g-C3N5 with a transition metal salt, and stirring; The intercalation type graphitic carbon nitride composite material is composed of graphitic carbon nitride g-C3N5 and transition metal atoms intercalated in the graphitic carbon nitride g-C3N5; Pyridine nitrogen atoms provide abundant coordination sites for transition metal atoms, and the van der Waals force between adjacent layers of g-C3N5 can stabilize transition metal atoms and prevent transition metal atoms from agglomerating into particles. The composite material can be stored stably; further, the interaction between adjacent layers will change the electronic structure of the transition metal atoms, thereby reducing the energy barrier of the reaction, so that the composite material can be used as a catalyst in the water desorption oxygen reaction.

Description of drawings

Fig. 1 is the scanning electron microscope photograph of the Ni/g-C3N5 prepared by the embodiment of the present invention 1;

Fig. 2 is the XRD pattern of Ni/g-C3N5 prepared in Example 1 of the present invention;

Fig. 3 is the K/g-C3N5 physical digital photo prepared by the embodiment of the present invention 1;

Fig. 4 is the Ni/g-C3N5 physical digital photo prepared by the embodiment of the present invention 1;

Fig. 5 is the EXAFS figure of Ir/g-C3N5 prepared in Example 4 of the present invention;

FIG. 6 is the LSV curve of the water desorption oxygen reaction of Ni/g-C3N5 prepared in Example 1 of the present invention under alkaline conditions.

Detailed ways

In order to further understand the present invention, the preferred embodiments of the present invention are described below in conjunction with the examples, but it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

Based on some problems still existing in the current method for large-scale synthesis of single atoms, the present application provides an intercalation type graphitic carbon nitride composite material and a preparation method thereof. Specifically, the embodiment of the present invention discloses an intercalation type graphitic carbon nitride composite material. The preparation method of the graphite-like carbon nitride composite material, comprising:

The graphite-like carbon nitride g-C3N5 intercalated with alkali metal ions is mixed with a transition metal salt and stirred to obtain an intercalated graphitic-like carbon nitride composite material.

In the above process of preparing the intercalated graphitic carbon nitride composite material (M/g-C3N5, M represents a transition metal atom), it is a graphitic carbon nitride g-C3N5 intercalated with alkali metal ions and a transition metal The intercalated graphitic carbon nitride composite material is obtained by mixing and stirring the salt; in this process, electrostatic ion exchange occurs between alkali metal ions and transition metal atoms; that is, the graphitic carbon nitride intercalated with alkali metal ions can promote the The cations in the transition metal salt solution are adsorbed to the surface of the material, and through ion exchange, the transition metal single atoms are stabilized by the confinement between the adjacent layers of the graphitic carbon nitride. The alkali metal ions are selected from K in a specific embodiment, and can also be selected from alkali metals such as Li or Na; taking the potassium ion intercalated graphitic carbon nitride as an example, it can be expressed as K/g-C3N5.

In the present application, it is necessary to prepare raw materials first, wherein one of the raw materials is an alkali metal ion intercalated graphitic carbon nitride can be prepared; the preparation method of the alkali metal ion intercalated graphitic carbon nitride is specifically:

After mixing the alkali metal bromide, 3-amino-1,2,4-triazole and water, evaporating and grinding to obtain mixed powder;

Primary calcination of the mixed powder to obtain the initial alkali metal ion intercalated graphitic carbon nitride g-C3N5;

The initial alkali metal ion intercalated graphitic carbon nitride g-C3N5 is calcined again to obtain the alkali metal ion intercalated graphitic carbon nitride g-C3N5.

In the above step of preparing the mixed powder, the raw materials are all chemically pure; the mass ratio of the alkali metal bromide to the 3-amino-1,2,4-triazole is (8-10): 100. During this process, the mixing temperature is 50-100°C.

The present application then performs primary calcination of the above mixed powder to obtain the initial alkali metal ion intercalated graphitic carbon nitride g-C3N5; the heating rate of the calcination is 10～15℃/min, and the calcination temperature is 500～ 600°C. This process yields microscopic bulk alkali metal ion intercalated graphitic carbon nitride g-C3N5.

Finally, the initial alkali metal ion intercalated graphitic carbon nitride g-C3N5 is calcined again to realize the exfoliation of the graphitic carbon nitride to obtain the alkali metal ion intercalated graphitic carbon nitride g-C3N5 with nanosheet structure.

For another raw material, the transition metal salt is a transition metal salt well known to those skilled in the art, and can be specifically selected from ferric nitrate nonahydrate, cobalt nitrate hexahydrate, manganese sulfate monohydrate, iridium chloride trihydrate or nickel nitrate hexahydrate . The mass ratio of the alkali metal ion intercalated graphitic carbon nitride g-C3N5 to the transition metal salt is 2:1. After the above two raw materials are mixed, the stirring is performed at a temperature of 50-100° C. and a time of 24-48 h. If the stirring time is too short, the single transition metal atom cannot completely replace the alkali metal ion.

The present application also provides an intercalation type graphitic carbon nitride composite material, which is composed of graphitic carbon nitride g-C3N5 and transition metal atoms intercalated in the graphitic carbon nitride g-C3N5.

In the above composite material, the transition metal atoms are all transition metal atoms well known to those skilled in the art, for example, they can be selected from nickel atoms, cobalt atoms, manganese atoms, iridium atoms or iron atoms. The transition metal atoms are stabilized by confinement between adjacent layers of graphitic carbon nitride g-C3N5.

The present application also provides the application of the above-mentioned intercalation type graphitic carbon nitride composite material in the water desorption oxygen reaction, specifically the water desorption oxygen reaction in an alkaline environment, and the intercalation type graphitic carbon nitride composite material material as a catalyst.

The intercalation type graphitic carbon nitride composite material provided by this application is composed of graphitic carbon nitride g-C3N5 and transition metal atoms intercalated in the graphitic carbon nitride g-C3N5; The electron-rich pyridine nitrogen atoms provide abundant coordination sites for transition metal atoms, and the van der Waals force between adjacent layers of g-C3N5 can stabilize the transition metal atoms and prevent the transition metal atoms from agglomerating into particles. As a result, the composite material can be stably preserved; further, the interaction between adjacent layers will change the electronic structure of the transition metal atoms, thereby reducing the energy barrier of the reaction, so that the composite material can be used as a water-resolving oxygen in the reaction. catalyst.

The intercalated graphitic carbon nitride composite material provided by the present application has great application prospects in photoelectric catalysis, energy storage, composite materials, etc. Compared with the existing transition metal single atoms, the synthesis method of the composite material Simple, large load, easy to mass-produce.

In order to further understand the present invention, the preparation method and application of the intercalation type graphitic carbon nitride composite material provided by the present invention will be described in detail below with reference to the examples. The protection scope of the present invention is not limited by the following examples.

Example 1

a. Dissolve 0.45g of potassium bromide powder and 5g of 3-amino-1,2,4-triazole in 30ml of deionized water, evaporate the water with magnetic stirring, and grind the obtained solid into powder;

b. The obtained powder was placed in an alumina crucible and covered, put into a muffle furnace, and calcined at 550°C for two hours at a heating rate of 15°C/min, and then the obtained solid was ground into powder to obtain brown Yellow powder bulk K/g-C3N5;

c. The synthesized powder was thermally exfoliated to form a nanosheet structure, that is, placed in a corundum ark and calcined at a heating rate of 15°C/min at 450°C in a tube furnace to form K/g-C3N5 nanosheet (as shown in Figure 3). Show);

d. Obtain 50mg K/g-C3N5nanosheet and mix with 20mg nickel nitrate hexahydrate and dissolve in 20mL aqueous solution and keep stirring;

e. The suspension obtained in step d is centrifuged to collect the precipitate, and the product is washed to neutrality by alternately washing 6 times with deionized water and ethanol to obtain the catalyst of transition metal Ni single-atom intercalation g-C3N5 (as shown in the figure). 4 shown).

Fig. 1 is the scanning electron microscope photograph of the Ni atom intercalation g-C3N5 composite material prepared in the present embodiment; Fig. 2 is the XRD pattern of g-C3N5, K/g-C3N5 and Ni/g-C3N5, from Fig. 1 and Fig. 2 It can be seen that in this example, a transition metal intercalated graphitic nitride-like carbon material was successfully prepared.

Dissolve 4mg Ni atom-intercalated g-C3N5 powder in 1mL solution, the solution composition is 500uL deionized water, 460uL absolute ethanol solution, 40uL nafion solution, and ultrasonically mix the above solution and powder for 30min to make it uniform; take 5uL mixed solution Dropped on the glassy carbon electrode (GC), after it was naturally dried, it was used as the working electrode, while the Ag/AgCl electrode was used as the reference electrode, the carbon rod was used as the counter electrode to form a three-electrode system, and the 1M KOH solution was used as the electrolyte solution; During the electrochemical LSV (Linear Scanning Voltammetry) test, the applied voltage range was 0-0.8V (VS RHE), and the scan rate was 5mV/s. The surface of the electrode was observed, and bubbles were precipitated; it can be seen that the intercalation of Ni atoms The g-C3N5 composites catalyze water splitting to generate oxygen under alkaline conditions. Fig. 6 is the LSV curve of the water-desorption oxygen reaction of Ni/g-C3N5 under alkaline conditions. It can be seen from Fig. 6 that the graphitic carbon nitride composite material intercalated by the transition metal single atom can be applied in the field of electrocatalysis.

Example 2

The difference between this embodiment and embodiment 1 is: in step a, the quality of potassium bromide is 0.75g, and other is the same as embodiment 1.

Example 3

The difference between this embodiment and embodiment 1 is: in step a, the potassium bromide quality is 1.5g, and other is the same as embodiment 1.

Example 4

The difference between this embodiment and embodiment 1 is that the transition metal salt in step d is iridium chloride trihydrate, thereby obtaining Ir atom intercalation g-C3N5 composite material; other is the same as embodiment 1. FIG. 5 is an EXAFS diagram of the Ir/g-C3N5 prepared in this example, and it can be seen from the diagram that the intercalated transition metal is in the form of a single atom.

Example 5

The difference between this embodiment and embodiment 1 is that the transition metal salt in step d is ferric chloride nonahydrate, thereby obtaining Fe atom intercalation g-C3N5 composite material; other is the same as embodiment 1.

Example 6

The difference between this embodiment and embodiment 1 is that the transition metal salt in step d is cobalt chloride hexahydrate, thereby obtaining a Co atom intercalated g-C3N5 composite material; the other is the same as embodiment 1.

Example 7

The difference between this embodiment and embodiment 1 is that the reactant in step a is thiourea, and the others are the same as those in embodiment 1.

The descriptions of the above embodiments are only used to help understand the method and the core idea of the present invention. It should be pointed out that for those skilled in the art, without departing from the principle of the present invention, several improvements and modifications can also be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

The above description of the disclosed embodiments enables any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (8)

1. a preparation method of intercalation type graphitic carbon nitride composite material, comprising: The graphite-like carbon nitride g-C3N5 intercalated with alkali metal ions is mixed with a transition metal salt and stirred to obtain an intercalated graphitic-like carbon nitride composite material. 2. preparation method according to claim 1, is characterized in that, the preparation method of the graphitic carbon nitride g-C3N of described alkali metal ion intercalation is specially: After mixing the alkali metal bromide, 3-amino-1,2,4-triazole and water, evaporating and grinding to obtain mixed powder; The mixed powder is primary calcined to obtain the initial alkali metal ion intercalated graphitic carbon nitride g-C3N5; The initial alkali metal ion intercalated graphitic carbon nitride g-C3N5 is calcined again to obtain the alkali metal ion intercalated graphitic carbon nitride g-C3N5. 3 . The preparation method according to claim 2 , wherein the temperature of the primary calcination is 500-600° C., and the temperature of the re-calcination is 400-500° C. 4 . 4 . The preparation method according to claim 1 or 2 , wherein the stirring temperature is 50-100° C., and the time is 24-48 h. 5 . 5. preparation method according to claim 1 and 2 is characterized in that, described transition metal salt is selected from ferric nitrate nonahydrate, cobalt nitrate hexahydrate, nickel nitrate hexahydrate, manganese sulfate monohydrate or iridium chloride trihydrate . 6. An intercalation type graphitic carbon nitride composite material, which is composed of graphitic carbon nitride g-C3N5 and transition metal atoms intercalated in the graphitic carbon nitride g-C3N5. 7 . The intercalated graphitic carbon nitride-like composite material according to claim 1 , wherein the transition metal atoms are selected from nickel atoms, cobalt atoms, iron atoms, manganese atoms or iridium atoms. 8 . 8. The intercalation type graphitic carbon nitride-like composite material prepared by the preparation method according to any one of claims 1 to 5 or the intercalation type graphitic carbon nitride-like composite material according to any one of claims 6 to 7 Application in Moisture Desorption Oxygen Reaction.

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