CN115108545A - Nitrogen-doped porous carbon-loaded monatomic molybdenum material and preparation method and application thereof - Google Patents

Nitrogen-doped porous carbon-loaded monatomic molybdenum material and preparation method and application thereof Download PDF

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CN115108545A
CN115108545A CN202210532249.1A CN202210532249A CN115108545A CN 115108545 A CN115108545 A CN 115108545A CN 202210532249 A CN202210532249 A CN 202210532249A CN 115108545 A CN115108545 A CN 115108545A
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nitrogen
molybdenum
porous carbon
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杨黎春
张家晴
袁斌
欧阳柳章
朱敏
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South China University of Technology SCUT
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Abstract

The invention discloses a nitrogen-doped porous carbon loaded monoatomic molybdenum material and a preparation method and application thereof. The invention adopts zinc molybdate as a precursor to be mixed and calcined with dicyandiamide, and then uses H 2 O 2 And etching to obtain the nitrogen-doped porous carbon-loaded monatomic molybdenum material. Use of H in the invention 2 O 2 Compared with the traditional method of preparing a porous structure by chlorine etching, hydrochloric acid, nitric acid and hydrofluoric acid etching and a high-temperature salt melting method, the method has the advantage of simpler and more convenient operation. The nitrogen-doped porous carbon loaded monatomic molybdenum material prepared by the invention has a large ratioThe surface area and abundant pores are provided, and meanwhile, nitrogen doping and well-dispersed monoatomic molybdenum doping are also provided, so that lithium ion adsorption is facilitated, and the lithium ion battery cathode material has good lithium storage performance.

Description

Nitrogen-doped porous carbon-loaded monatomic molybdenum material and preparation method and application thereof
Technical Field
The invention belongs to the field of new material preparation, and particularly relates to a nitrogen-doped porous carbon-loaded monatomic molybdenum material, and a preparation method and application thereof.
Background
In recent years, a catalytic material (SACS) supporting a metal monoatomic atom has received much attention because of its high catalytic activity. The monatomic material is characterized in that metal elements are uniformly dispersed on a specific carrier in a limited monatomic form, the atom utilization rate can reach 100%, and the selectivity, the electrochemical activity and the stability of the monatomic material are superior to those of the traditional nano metal material. After the metal monoatomic doping, the atom coordination environment is changed, so that the charge performance is shown, the electrochemical activity is enhanced, and the conductivity of the material is improved. For example, monatomic ruthenium/palladium/platinum/gold monatomic materials are often reported as high-efficiency catalytic materials in the fields of carbon dioxide electroreduction, oxygen reduction, water decomposition, carbon-containing small molecule compound conversion and the like. However, the noble metal has high cost and is not beneficial to practical production and application. In consideration of economic efficiency, non-noble metal monatomic materials, such as monatomic cobalt and monatomic nickel materials, which are developed in succession, are increasingly favored by researchers due to high activity and stability. In the field of lithium ion batteries, nitrogen-doped porous carbon-loaded metal monatomic materials are gradually studied as negative electrode materials. The porous structure can enhance the infiltration of the electrolyte and promote the rapid diffusion of ions; the metal single atom doping can promote electron transfer and enhance lithium ion adsorption, thereby improving the lithium storage performance (chem.eng.j.,2020,389,124377 and the like). The development of metal monatomic materials with different types and high performance is of great significance in promoting the development of monatomic materials.
At present, the preparation of the monatomic material mainly comprises a metal organic framework carbonization method, a wet chemical method, an atomic layer deposition method and the like. The preparation of metal-organic framework precursors requires the use of expensive reagents and the metal species are relatively limited. For example, patent "bifunctional catalyst and method for preparing the same, metal-air battery" provides a method for preparing bifunctional catalyst, which comprises mixing a metal organic framework and a transition metal compound, irradiating with ultraviolet ozone, and loading transition metal oxide and transition metal single atom on a nitrogen-doped carbon nanotube simultaneously by using a chemical vapor deposition method. The method has high cost and poor stability of the metal organic framework material formed by the coordination bond; the wet chemical method requires precise preparation of a metal salt solution with a certain concentration, the synthesis path is complicated, metal monoatomic ions are easily agglomerated due to overhigh concentration, and toxic waste liquid is easily generated. For example, in the patent "a nitrogen-doped carbon-anchored ruthenium-sulfur-nitrogen monatomic material, a preparation method and applications thereof" firstly, cobalt salt, ruthenium salt, 2-methylimidazole, N-dimethylformamide, N-diethylformamide, methanol and the like are used to prepare a ruthenium-doped cobalt-based zeolite imidazolate organic framework precursor, nitrogen-doped carbon-supported cobalt particles and ruthenium-sulfur-nitrogen monatomic are prepared by high-temperature roasting, and the nitrogen-doped carbon-anchored ruthenium-sulfur-nitrogen monatomic is obtained after pickling with sulfuric acid and freeze-drying. The preparation process is complex and is easy to cause toxic organic waste liquid. The ald technique requires expensive experimental equipment and strict control of reaction parameters such as temperature and time. At present, the problems of complicated preparation process, high preparation cost, monatomic aggregation and the like still exist in the preparation of non-noble metal monatomic materials, and the obtaining of metal monatomic materials with high economic benefits and good dispersion is still a great challenge.
Patent "a monatomic molybdenum-nitrogen-carbon nanosheet material, preparation and application thereof" provides a preparation method of the monatomic molybdenum-nitrogen-carbon nanosheet material, comprising the steps of carbonizing a silicon dioxide-coated graphene oxide nanosheet, a nitrogen carbon source and a molybdenum salt mixture through heat treatment, and finally etching with alkali liquor and acid liquor to remove silicon dioxide and molybdenum carbide particles to obtain 0.2% -1% of molybdenum monatomic load. According to the method, the silicon dioxide is etched by using the strong base, and then the molybdenum carbide is etched by using the strong acid, so that the process is somewhat complicated, more corrosive waste liquid is easily generated, and the load capacity of the molybdenum monoatomic group is not high. Therefore, the development and operation of the monatomic molybdenum material which is safe and environment-friendly and has high loading capacity is of great significance.
Disclosure of Invention
Objects of the inventionAims to provide a nitrogen-doped porous carbon-loaded monatomic molybdenum material, a preparation method and application thereof. The preparation method is simple to operate and has higher economic benefit, the high-cost atomic layer deposition technology, the high-temperature metal carbide organic framework method and the like are not needed, the etching of strong acid or strong alkali and the like is not needed, and only H is used 2 O 2 And etching is carried out. The prepared carbon material has rich pore structure, short lithium ion diffusion path and fast reaction kinetics. The doped monatomic molybdenum changes the electronic structure of the surface of the electrode material and enhances the adsorption of lithium ions. The preparation method is simple and easy to implement, and the prepared nitrogen-doped porous carbon-loaded monatomic molybdenum material shows good electrochemical performance when being used as a lithium ion battery cathode material.
The purpose of the invention is realized by the following technical scheme.
A preparation method of a nitrogen-doped porous carbon-loaded monatomic molybdenum material comprises the following steps:
(1) ZnMoO synthesis by hydrothermal method 4 : dissolving sodium molybdate and zinc nitrate in a high-pressure reaction kettle by using water as a solvent, screwing the reaction kettle tightly, and placing the reaction kettle in an air-blast drying box for hydrothermal reaction;
(2) ZnMoO obtained in the step (1) 4 Grinding and mixing the mixture with dicyandiamide, and then placing the mixture in the center of a quartz tube in a tube furnace for calcining to obtain a molybdenum carbide/carbon composite material;
(3) weighing the molybdenum carbide/carbon composite material obtained in the step (2), and adding H into the molybdenum carbide/carbon composite material 2 O 2 Then stirring and reacting at normal temperature; and after the reaction, washing, filtering and drying the product to obtain the nitrogen-doped porous carbon loaded monatomic molybdenum material.
Preferably, the mass ratio of the zinc nitrate to the sodium molybdate in the step (1) is 1: 0.55-1: 0.75, and more preferably 1: 0.65.
Preferably, the temperature of the hydrothermal reaction in the step (1) is 140-180 ℃, and more preferably 160 ℃; the time of the hydrothermal reaction is 8-16 h, and more preferably 12 h.
Preferably, the ZnMoO of step (2) 4 The mass ratio of the dicyandiamide to the dicyandiamide is 1: 8-1: 12, and ZnMoO is further preferable 4 The mass ratio of the dicyandiamide to the dicyandiamide is 1: 10.
Preferably, the specific procedure of the calcination in step (2) is as follows: firstly, heating from room temperature to 350-550 ℃, preserving heat for 1-3 h, then heating to 750-850 ℃, preserving heat for 1-3 h; the calcining atmosphere is Ar gas. More preferably: the temperature is firstly increased from room temperature to 450 ℃ and kept for 2h, and then the temperature is increased to 800 ℃ and kept for 2 h.
Preferably, the molybdenum carbide/carbon composite material of step (3) is mixed with H 2 O 2 The mass-to-volume ratio of (1) to (0.2-0.3) mg/mL, and more preferably 1:0.25 mg/mL.
Preferably, the time for the normal-temperature stirring reaction in the step (3) is 8-16 h, and more preferably 12 h.
The invention also provides the nitrogen-doped porous carbon-loaded monatomic molybdenum material prepared by the preparation method. Has the following characteristics:
(1) the specific surface area of the nitrogen-doped porous carbon-loaded monatomic molybdenum material is 813m 2 /g～1129m 2 /g；
(2) The nitrogen-doped porous carbon-loaded monatomic molybdenum material has a rich pore structure, and the total pore volume is 1.16cm 3 /g～1.74cm 3 /g；
(3) The nitrogen-doped porous carbon-loaded monatomic molybdenum material is loaded with metal molybdenum distributed in a monatomic form, and the content of the metal molybdenum is 0.60-2.48 wt%.
The invention also provides application of the nitrogen-doped porous carbon-loaded monatomic molybdenum material as a lithium ion battery cathode material. Under the current density of 0.1A/g, the reversible capacity of the assembled lithium ion battery can reach 1212mAh/g, and the assembled lithium ion battery can be cycled for more than 2000 times under the current density of 1A/g, and the capacity retention rate is 87%.
According to the invention, zinc molybdate is used as a precursor and a catalyst, a cyanamide compound is catalyzed to carbonize and react with the zinc molybdate to generate molybdenum carbide in the high-temperature roasting process, the molybdenum carbide is uniformly dispersed in nitrogen-doped carbon in the form of nanoparticles, and meanwhile, Zn volatilizes at high temperature to form a porous structure; in the following H 2 O 2 During the etching process, most of the molybdenum carbide is oxidized and dissolved, a large amount of pores are further formed,a small amount of molybdenum is captured by carbon atoms to form uniformly dispersed monatomic load, and finally the porous carbon material with nitrogen doping and monatomic molybdenum load is obtained.
The cyanamide compound has high nitrogen content, but is easy to crack and volatilize in the carbonization process, and the carbonization rate is low. In the preparation process, zinc molybdate provides a molybdenum source, and has the functions of catalyzing carbonization and pore-forming agent, so that higher carbonization rate and nitrogen doping rate are finally obtained. In addition, H is used as compared to conventional metal organic framework carbonization and atomic layer deposition techniques 2 O 2 The method for etching the molybdenum carbide particles can obtain a porous structure, can also obtain molybdenum monatomic load with good dispersibility, and has safer and more environment-friendly preparation process and higher economic benefit. The nitrogen doping and the single atom molybdenum loading effectively regulate and control the electronic structure and the chemical state of the surface of the carbon material, the lithium ion adsorption strength is enhanced, and the material as a lithium ion battery cathode material shows high capacity and excellent cycle stability.
Compared with the prior art, the invention has the following advantages:
(1) the etchant used in the invention is H 2 O 2 The method is applied to the preparation of the monatomic material for the first time. Compared with the preparation process of carrying out one-step etching or multi-step etching by using toxic chlorine, strong acid and strong alkali solution, the preparation process is simpler; compared with an atomic layer deposition technology or a metal organic framework carbonization method, the method for obtaining the metal monatomic load by etching the carbide does not need expensive equipment and reagents, and has higher economic benefit.
(2) The nitrogen-doped porous carbon loaded monatomic molybdenum material obtained by the invention has rich micropores and mesopores, the porous structure is favorable for electrolyte infiltration and ion diffusion, the volume expansion of an electrode material in the charging and discharging process can be relieved, and the reaction kinetics and the cycling stability are favorably improved.
(3) The nitrogen-doped porous carbon-loaded monatomic molybdenum material obtained by the method contains a layered graphite carbon structure and an amorphous carbon structure. The highly conductive layered graphite carbon structure is beneficial to electron transmission, and the amorphous carbon has a lower diffusion energy barrier and is beneficial to lithium ion diffusion.
(4) The material obtained by the invention is a nitrogen-doped porous carbon material. The nitrogen doping can increase the conductivity of the carbon material and form a new lithium storage site, which is beneficial to improving the lithium storage performance.
(5) The material prepared by the invention is loaded with well-dispersed monatomic molybdenum, so that the electrical conductivity of the carbon material is enhanced, and the unique metal monatomic coordination is beneficial to enhancing the adsorption of lithium ions, thereby obtaining higher lithium storage capacity.
Drawings
Fig. 1 is an XRD pattern of the nitrogen-doped porous carbon-supported monatomic molybdenum material obtained in example 1.
Fig. 2 is a pore size distribution diagram of the nitrogen-doped porous carbon-supported monatomic molybdenum material obtained in example 1.
Fig. 3 is a scanning electron microscope image of the nitrogen-doped porous carbon-supported monatomic molybdenum material obtained in example 1.
Fig. 4 is a spherical aberration corrected transmission electron microscope image of the nitrogen doped porous carbon supported monatomic molybdenum material obtained in example 1.
Fig. 5 is a high resolution XPS plot of N1s for the nitrogen doped porous carbon-supported monatomic molybdenum material obtained in example 1.
Fig. 6 is a charge-discharge cycle diagram of the nitrogen-doped porous carbon-supported monatomic molybdenum material obtained in example 1 at a current density of 0.1A/g.
FIG. 7 is a charge-discharge cycle diagram of the nitrogen-doped porous carbon-supported monatomic molybdenum material obtained in example 1 at a current density of 1A/g.
Detailed Description
The invention is described in further detail below with reference to the figures and specific embodiments. Unless otherwise specified, various reagents and chemicals used in the present invention are commercially available or can be obtained by known production methods.
Example 1
The nitrogen-doped porous carbon-loaded monatomic molybdenum material of the embodiment is specifically prepared by the following steps:
the first step of reaction: ZnMoO synthesis by hydrothermal method 4 The precursor comprises the following steps:
(1) dissolving zinc nitrate and sodium molybdate in water and stirring to obtain a mixed solution, wherein the mass ratio of the zinc nitrate to the sodium molybdate is 1: 0.65;
(2) pouring the obtained mixed solution into a high-pressure reaction kettle, and preserving heat for 12 hours at 160 ℃;
(3) after the reaction is finished, the obtained product is filtered, washed by deionized water and ethanol respectively and dried to obtain ZnMoO 4 。
The second step of reaction: the preparation method of the molybdenum carbide/carbon composite material comprises the following specific steps:
(1) weigh 100mg ZnMoO 4 And 1g of dicyandiamide powder in a mortar, and grinding to uniformly mix the dicyandiamide powder and the mortar;
(2) placing the ground powder in an alumina porcelain boat, covering the alumina porcelain boat with a cover, placing the alumina porcelain boat in the center of a quartz tube of a tube furnace, and introducing argon atmosphere for 2 hours to exhaust air in the tube;
(3) and (4) after the exhaust is finished, performing high-temperature calcination under the protection atmosphere of Ar gas. Firstly, the room temperature is increased to 450 ℃ and the temperature is kept for 2h, and then the temperature is increased to 800 ℃ and the temperature is kept for 2 h. And after the heat preservation is finished and the temperature is reduced to the room temperature, collecting a fluffy spongy sample in the porcelain boat, and grinding to obtain the molybdenum carbide/carbon composite material.
The third step of reaction: dissolving the molybdenum carbide/carbon composite material powder obtained by the second step reaction in 30 percent H 2 O 2 Stirring to remove the molybdenum carbide nanoparticles, and specifically comprising the following steps of:
(1) weigh 100mg of the molybdenum carbide/carbon composite powder obtained in the second step into a beaker, weigh 25mL of H 2 O 2 And added dropwise into a beaker, followed by a stirring reaction for 12 hours;
(2) after the reaction, suction filtration was performed. And washing with deionized water and drying to obtain the nitrogen-doped porous carbon-loaded monatomic molybdenum material.
Fig. 1 is an XRD pattern of the nitrogen-doped porous carbon-supported monatomic molybdenum material obtained in example 1. The diffraction broad peaks at 23.4 ° and 43.3 ° in the figure correspond to the (002) and (100) crystal planes of graphitic carbon, respectively, with no other peaks. The prepared material has high purity and higher graphite carbon content, and is beneficial to improving the conductivity.
Fig. 2 is a pore size distribution diagram of the nitrogen-doped porous carbon-supported monatomic molybdenum material obtained in example 1. The pore diameters of the material are intensively distributed at 0.52nm, 1.00nm and 4.52nm, and the material is a material with coexisting micropores and mesopores, which shows that the material has abundant micropore and mesopore structures.
Fig. 3 is a scanning electron microscope image of the nitrogen-doped porous carbon-supported monatomic molybdenum material obtained in example 1, which shows that the morphology is a fluffy and porous flocculent morphology.
Fig. 4 is a transmission electron microscope image of the spherical aberration correction of the nitrogen-doped porous carbon-supported monatomic molybdenum material obtained in example 1, which shows that the material is supported by monatomic molybdenum, has a supporting amount of about 1.66 wt%, and is well-dispersed without significant aggregation.
Fig. 5 is a high resolution XPS plot of N1s for the nitrogen-doped porous carbon-supported monatomic molybdenum material obtained in example 1, indicating that nitrogen is mainly present as pyrrole nitrogen, pyridine nitrogen, and graphitized nitrogen.
Fig. 6 is a charge-discharge cycle diagram of the nitrogen-doped porous carbon-supported monatomic molybdenum material obtained in example 1 at a current density of 0.1A/g. After the obtained nitrogen-doped porous carbon-loaded monatomic molybdenum material is cycled for 100 times under the current density of 0.1A/g, the obtained nitrogen-doped porous carbon-loaded monatomic molybdenum material still has the lithium storage capacity of 1212mA h/g, which indicates that the nitrogen-doped porous carbon-loaded monatomic molybdenum material shows high lithium storage performance in a lithium ion battery.
Fig. 7 is a charge-discharge cycle diagram of the nitrogen-doped porous carbon-supported monatomic molybdenum material obtained in example 1 at a current density of 1A/g. After the obtained nitrogen-doped porous carbon loaded monatomic molybdenum material is cycled for 2000 times under the current density of 1A/g, 623mAh/g can be still provided, and the capacity retention rate is 87%, which shows that the nitrogen-doped porous carbon loaded monatomic molybdenum material shows excellent cycling stability in a lithium ion battery.
Example 2
Example 2 the conditions and procedure are essentially the same as example 1, except that: in the hydrothermal reaction in the first step, the mass ratio of zinc nitrate to sodium molybdate is 1: 0.55.
Example 3
Example 3 the conditions and procedure are essentially the same as in example 1, except that: in the hydrothermal reaction in the first step, the mass ratio of zinc nitrate to sodium molybdate is 1: 0.75.
Example 4
Example 4 the conditions and procedure were essentially the same as example 1, except that: the hydrothermal reaction temperature in the first step was 140 ℃.
Example 5
Example 5 the conditions and procedure are essentially the same as example 1, except that: the hydrothermal reaction temperature in the first step was 180 ℃.
Example 6
Example 6 the conditions and procedure were essentially the same as example 1, except that: the hydrothermal reaction time of the first step is 8 h.
Example 7
Example 7 the conditions and procedure are essentially the same as example 1, except that: the hydrothermal reaction time of the first step is 16 h.
Example 8
Example 8 the conditions and procedure are essentially the same as example 1, except that: 100mg of ZnMoO was weighed in the second reaction 4 And 0.8g dicyandiamide powder.
Example 9
Example 9 the conditions and procedure are essentially the same as example 1, except that: 100mg of ZnMoO was weighed in the second reaction 4 And 1.2g dicyandiamide powder.
Example 10
Example 10 the conditions and procedure are essentially the same as example 1, except that: the high-temperature calcination process of the second step reaction is as follows: firstly, heating from room temperature to 350 ℃, preserving heat for 2h, and then heating to 800 ℃, preserving heat for 2 h; the calcining atmosphere is Ar gas.
Example 11
Example 11 the conditions and procedure are essentially the same as example 1, except that: the high-temperature calcination process of the second step reaction is as follows: firstly, heating from room temperature to 550 ℃, preserving heat for 2h, and then heating to 800 ℃, preserving heat for 2 h; the calcining atmosphere is Ar gas.
Example 12
Example 12 the conditions and procedure are essentially the same as example 1, except that: the high-temperature calcination process of the second step reaction is as follows: firstly, heating from room temperature to 450 ℃ and preserving heat for 2h, and then heating to 750 ℃ and preserving heat for 2 h; the calcination atmosphere was Ar gas.
Example 13
Example 13 the conditions and procedure are essentially the same as example 1, except that: the high-temperature calcination process of the second step reaction is as follows: firstly, heating from room temperature to 450 ℃, preserving heat for 2h, and then heating to 850 ℃, preserving heat for 2 h; the calcining atmosphere is Ar gas.
Example 14
Example 14 the conditions and procedure are essentially the same as example 1, except that: the high-temperature calcination process of the second step reaction is as follows: firstly, heating from room temperature to 450 ℃ and preserving heat for 1h, and then heating to 800 ℃ and preserving heat for 1 h; the calcining atmosphere is Ar gas.
Example 15
Example 15 the conditions and procedure are essentially the same as example 1, except that: the high-temperature calcination process of the second step reaction is as follows: firstly, heating from room temperature to 450 ℃ and preserving heat for 3h, and then heating to 800 ℃ and preserving heat for 3 h; the calcining atmosphere is Ar gas.
Example 16
Example 16 the conditions and procedure are essentially the same as example 1, except that: h of the third reaction 2 O 2 The volume was 20 mL.
Example 17
Example 17 the conditions and procedure are essentially the same as example 1, except that: h of the third reaction stage 2 O 2 The volume was 30 mL.
Example 18
Example 18 the conditions and procedure are essentially the same as example 1, except that: the stirring time of the reaction in the third step is 8 hours.
Example 19
Example 19 the conditions and procedure are essentially the same as example 1, except that: the stirring time of the reaction in the third step is 16 h.
The nitrogen-doped porous carbon-loaded monatomic molybdenum material obtained in examples 1 to 19 was used as a lithium ion battery negative electrode material, and mixed with a conductive agent and a binder in the following ratio of 8: 1:1, dissolving the mixture in water, and uniformly stirring to obtain slurry. Uniformly mixing the pasteCoating on copper foil, and drying at 80 ℃ for 12h in a vacuum drying oven. After the temperature is returned to room temperature, the electrode plate is blanked into a circular electrode plate with the diameter of 12mm and is used as a working electrode, wherein the loading amount of active substances is controlled to be 0.8-1.2 mg/cm 2 . Assembly of CR2016 type button cell was performed in a glove box filled with high concentration argon, with a metal lithium sheet as the counter electrode and a Celgard 2400 polypropylene porous membrane as the separator. The adopted electrolyte comprises the following components: 1M LiPF6 was used as solute, EC: DEC (volume ratio of 1:2) organic mixture was used as solvent, and 10% FEC was used as additive. And (3) carrying out electrochemical performance test on the assembled button half cell, and carrying out constant current charge and discharge test on the experimental cell by adopting a CT2001A type LAND cell test system.
When the nitrogen-doped porous carbon-loaded monatomic molybdenum material obtained in the embodiments 1 to 15 is used as a negative electrode material of a lithium ion battery, the lithium storage capacity is 1160-1212 mAh/g after 100 cycles at 0.1A/g, which indicates that the preparation condition and the carbonization condition of the precursor have no obvious influence on the lithium storage performance of the finally obtained nitrogen-doped porous carbon-loaded monatomic molybdenum material. Specific surface areas, total pore volumes, molybdenum contents and lithium storage capacities of the nitrogen-doped porous carbon-supported monatomic molybdenum materials obtained in example 1 and examples 16 to 19 are shown in table 1. Increase of H 2 O 2 The amount of (1) (example 17) or the extended stirring time (example 19) can result in a larger specific surface area and more abundant pores, but results in a decrease in the loading of molybdenum metal, resulting in a decrease in the number of lithium ion adsorption sites. To reduce H 2 O 2 The amount of (1) (example 16) or the stirring time (example 18) can increase the molybdenum loading, but the etching effect is weakened, so that the specific surface area and the total pore volume are reduced, and the electrolyte infiltration and the lithium ion diffusion are not facilitated. Illustrates the control of the etching parameter (H) 2 O 2 Usage amount, stirring reaction time duration) can adjust the structure and performance of the nitrogen-doped porous carbon-loaded monatomic molybdenum material, wherein the nitrogen-doped porous carbon-loaded monatomic molybdenum material of example 1 has moderate specific surface area, pore volume and metal molybdenum loading amount, and ensures sufficient lithium storage active sites while possessing rapid lithium ion diffusion kinetics, thereby obtaining the highest lithium storage capacityThe amount was 1212mA h/g.
TABLE 1
Figure BDA0003637312350000081
While the foregoing is directed to the preferred embodiment of the present invention, it will be understood that the scope of the invention is not limited thereto. Modifications and equivalents may be made by those skilled in the art within the scope of the disclosure as expressed in the claims and are intended to be included within the scope of the invention.

Claims (10)

1. The preparation method of the nitrogen-doped porous carbon-loaded monatomic molybdenum material is characterized by comprising the following steps of:
(1) ZnMoO synthesis by hydrothermal method 4 ；
(2) ZnMoO obtained in the step (1) 4 Grinding and mixing the molybdenum carbide powder and dicyandiamide, and then placing the mixture in a quartz tube in a tube furnace for calcining to obtain a molybdenum carbide/carbon composite material;
(3) weighing the molybdenum carbide/carbon composite material obtained in the step (2), and adding H into the molybdenum carbide/carbon composite material 2 O 2 Then stirring and reacting at normal temperature; and after the reaction, washing, filtering and drying the product to obtain the nitrogen-doped porous carbon loaded monatomic molybdenum material.
2. The method for preparing the nitrogen-doped porous carbon-supported monatomic molybdenum material according to claim 1, wherein the hydrothermal method in the step (1) is specifically: dissolving sodium molybdate and zinc nitrate in a high-pressure reaction kettle by using water as a solvent, screwing the reaction kettle tightly, and then placing the reaction kettle in an air-blast drying box for hydrothermal reaction.
3. The preparation method of the nitrogen-doped porous carbon-supported monatomic molybdenum material according to claim 2, wherein the temperature of the hydrothermal reaction is 140-180 ℃, and the time of the hydrothermal reaction is 8-16 h.
4. The preparation method of the nitrogen-doped porous carbon-supported monatomic molybdenum material according to claim 1, wherein the mass ratio of the zinc nitrate to the sodium molybdate in the step (1) is 1: 0.55-1: 0.75.
5. The method for preparing nitrogen-doped porous carbon-supported monatomic molybdenum material according to claim 1, wherein the ZnMoO in the step (2) 4 The mass ratio of the dicyandiamide to the dicyandiamide is 1: 8-1: 12.
6. The preparation method of the nitrogen-doped porous carbon-supported monatomic molybdenum material according to claim 1, wherein the calcination in the step (2) is specifically performed by: firstly, heating from room temperature to 350-550 ℃, preserving heat for 1-3 h, then heating to 750-850 ℃, and preserving heat for 1-3 h; the calcining atmosphere is Ar gas.
7. The method for preparing the nitrogen-doped porous carbon-supported monatomic molybdenum material of claim 1, wherein in step (3) the molybdenum carbide/carbon composite material is mixed with H 2 O 2 The mass-to-volume ratio of (1) mg/mL to (0.2-0.3).
8. The preparation method of the nitrogen-doped porous carbon-supported monatomic molybdenum material of claim 1, wherein the reaction time of the stirring at normal temperature in the step (3) is 8-16 hours.
9. A nitrogen-doped porous carbon-supported monatomic molybdenum material obtained by the production method described in any one of claims 1 to 8.
10. The use of the nitrogen-doped porous carbon-supported monatomic molybdenum material of claim 9 as a lithium ion battery negative electrode material.
CN202210532249.1A 2022-05-10 2022-05-10 Nitrogen-doped porous carbon-loaded monatomic molybdenum material and preparation method and application thereof Pending CN115108545A (en)

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Publication number Priority date Publication date Assignee Title
CN115786962A (en) * 2022-12-19 2023-03-14 天津大学 Metal and nonmetal double-doped amorphous carbon material and preparation method and application thereof

Non-Patent Citations (3)

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Title
PENG DU等: "Anchoring Mo single atoms/clusters and N on edge-rich nanoporous holey graphene as bifunctional air electrode in Zn−air batteries" *
PENGPENG TAO等: "Porous graphitic carbon prepared from the catalytic carbonization of Mo-containing resin for supercapacitors" *
QING CAO等: "Tailored synthesis of Zn–N co-doped porous MoC nanosheets towards efficient hydrogen evolution" *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115786962A (en) * 2022-12-19 2023-03-14 天津大学 Metal and nonmetal double-doped amorphous carbon material and preparation method and application thereof

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