阅读说明：本技术 一种新结构金属有机框架材料、其衍生的金属氮碳催化剂及其制备方法与应用 (Metal organic framework material with novel structure, metal nitrogen carbon catalyst derived from metal organic framework material, and preparation method and application of metal nitrogen carbon cat) 是由 罗浩 田梦 于 2021-07-16 设计创作，主要内容包括：本发明公开了一种新结构金属有机框架材料、其衍生的金属氮碳催化剂及其制备方法与应用,该金属有机框架材料的化学式为：M(C-(6)H-(7)NO-(6))(H-(2)O),其中M为Ni、Co或NiCo。本发明合成的金属有机框架材料具有新颖的晶体结构,其衍生物金属氮碳材料具有高密度且均匀分布的金属颗粒,具有丰富的金属位点,从而拥有丰富的催化活性中心；本发明提供的衍生物金属氮碳材料可作为金属-空气电池或燃料电池的阴极氧还原催化剂使用,并且催化性能优异,与现有的其它非贵金属材料相比具有极高的氧还原活性,且其性能接近商业铂碳催化剂,是贵金属氧还原催化剂的潜力替代者。(The invention discloses a metal organic framework material with a new structure, a metal nitrogen carbon catalyst derived from the metal organic framework material, a preparation method and an application of the metal nitrogen carbon catalyst, wherein the metal organic framework material has a chemical formula as follows: m (C) 6 H 7 NO 6 )(H 2 O), wherein M is Ni, Co or NiCo. The metal organic framework material synthesized by the invention has a novel crystal structure, and the derivative metal nitrogen carbon material has high-density and uniformly distributed metal particles and abundant metal sites, so that the metal organic framework material has abundant catalytic activity centers; the derivative metal nitrogen carbon material provided by the invention can be used as a cathode oxygen reduction catalyst of a metal-air battery or a fuel battery, has excellent catalytic performance, has extremely high oxygen reduction activity compared with other existing non-noble metal materials, has performance close to that of a commercial platinum carbon catalyst, and is a potential substitute of a noble metal oxygen reduction catalyst.)

1. A new structure metal organic frame material is characterized in that: the chemical formula of the metal organic framework material is as follows: m (C)₆H₇NO₆)(H₂O), abbreviated as M-NTA, wherein M is Ni, Co or NiCo.

2. The new structural metal organic framework material as claimed in claim 1, wherein: the unit cell parameters of the metal organic framework material are as follows:α＝β＝90°、γ＝120°。

3. the new structural metal organic framework material as claimed in claim 1, wherein: the metal organic framework material is obtained by the solvothermal reaction of at least one metal salt of Ni and Co and nitrilotriacetic acid NTA.

4. A preparation method of the new structure metal organic framework material as claimed in any one of claims 1 to 3, characterized in that: adding at least one metal salt of Ni and Co and aminotriacetic acid ligand into a solvent formed by at least one of water and isopropanol, reacting for 0.5-100 h at 60-250 ℃, centrifuging, collecting precipitate, washing and drying to obtain the metal organic framework material.

5. The method of claim 4, wherein: the feeding molar ratio of the metal salt to the ligand is 1: 0.1-10.

6. A metal nitrogen carbon catalyst characterized by: the metal nitrogen carbon catalyst is obtained by calcining the metal organic framework material with the new structure in any one of claims 1-3 in an inert atmosphere.

7. The metallic nitrogen-carbon catalyst of claim 6, wherein: the inert atmosphere is at least one of nitrogen, argon and helium.

8. The metal nitrogen carbon catalyst of claim 6, wherein the calcining conditions are: the calcination temperature is 300-1500 ℃, the calcination time is 0.5-10 h, and the heating rate is 0.5-100 ℃/min.

9. Use of the metal nitrogen carbon catalyst according to any one of claims 6 to 8, wherein: for use as a metal-air cell cathode oxygen reduction catalyst or a fuel cell cathode oxygen reduction catalyst.

10. A metal-air battery or a fuel cell using the metal nitrogen-carbon catalyst according to any one of claims 6 to 8 as a cathode oxygen reduction catalyst.

Technical Field

The invention relates to the technical field of metal organic framework materials, in particular to a metal organic framework material with a new structure, a metal nitrogen carbon catalyst derived from the metal organic framework material, and a preparation method and application of the metal nitrogen carbon catalyst.

Background

The Metal Organic Framework (MOF) material is a coordination polymer which develops rapidly in the last two decades, has a three-dimensional pore channel structure, and generally takes metal ions as a linking point and is supported by organic ligands to form a novel porous material with a spatially three-dimensional extension. The carbon composite material and the carbon composite material derived from the metal organic framework have wide application in catalysis, energy storage and separation. Therefore, the development of MOF materials with novel crystal structures is of great significance for enriching the MOF family and developing new materials derived from the MOF family.

In recent years, the cathode oxygen reduction reaction of metal air batteries and fuel cells has been studied in great quantity due to its importance, and metal nitrogen carbon materials are non-noble metal catalysts having excellent oxygen reduction performance. Among them, the preparation of metal nitrogen carbon material by calcination and derivation of metal organic framework material is a preparation method which is widely favored by researchers. Because the metal organic framework has the structural advantages of large specific surface area, excellent pore channel structure, abundant metal sites and the like, the calcined and derived metal nitrogen-carbon material always inherits the advantages and has large specific surface area and excellent pore channel mass transfer structure. However, it is a challenge to obtain high-density and uniformly-distributed metal particles in a metal nitrogen carbon material, such as a commonly-used MOF precursor ZIF-67, which is calcined by a large number of researchers to obtain a cobalt nitrogen carbon catalyst, but since the Co-Co bond length in the ZIF-67 is short, the cobalt nitrogen carbon catalyst is easy to agglomerate in the calcination process, and the obtained metal nitrogen carbon material is often large in particle and non-uniform in distribution. The density of metal particles has a great influence on the activity of the catalyst, and in an actual metal air battery electrode or a fuel cell membrane electrode, the smaller the loading amount is, the thinner the catalyst layer of the catalyst is, and the better the mass transfer is, so that under the same loading amount, the catalyst with high density and uniformly distributed active sites forms a thinner catalyst layer, and the better the performance is. The distance of the metal sites in the calcined precursor MOF structure and the structural characteristics such as the ligand types often determine the structure and morphological characteristics of the derived materials. Therefore, the MOF material with a new structure and the metal nitrogen carbon catalyst with derived high-density metal particle sites have important significance for oxygen reduction reaction in metal air batteries and fuel cells.

Disclosure of Invention

The invention aims to provide a metal organic framework material with a novel structure, a metal nitrogen carbon catalyst derived from the metal organic framework material, and a preparation method and application of the metal nitrogen carbon catalyst.

The invention adopts the following technical scheme for realizing the purpose:

the invention firstly discloses a new structure metalMachine frame material, its characteristics lie in: the chemical formula of the metal organic framework material is as follows: m (C)₆H₇NO₆)(H₂O), abbreviated as M-NTA, wherein M is Ni, Co or NiCo.

Further, the unit cell parameter of the metal-organic framework material isα＝β＝90°、γ＝120°。

Further, the metal organic framework material is obtained by the solvothermal reaction of at least one metal salt of Ni and Co and nitrilotriacetic acid NTA.

The preparation method of the metal organic framework material with the new structure comprises the following steps: adding at least one metal salt of Ni and Co and aminotriacetic acid ligand into a solvent formed by at least one of water and isopropanol, reacting for 0.5-100 h at 60-250 ℃, centrifuging, collecting precipitate, washing and drying to obtain the metal organic framework material.

Furthermore, the feeding molar ratio of the metal salt to the ligand is 1: 0.1-10.

The invention also discloses a metal nitrogen carbon catalyst which is obtained by calcining the metal organic framework material with the new structure in an inert atmosphere.

Further, the inert atmosphere is at least one of nitrogen, argon and helium.

Further, the calcining conditions are as follows: the calcination temperature is 300-1500 ℃, the calcination time is 0.5-10 h, and the heating rate is 0.5-100 ℃/min.

The metal nitrogen carbon catalyst obtained by the invention can be used as a metal-air battery cathode oxygen reduction catalyst or a fuel battery cathode oxygen reduction catalyst.

Compared with the prior art, the invention has the beneficial effects that:

1. the metal organic framework material synthesized by the invention has a novel crystal structure, and the derivative metal nitrogen carbon material has high-density and uniformly distributed metal particles and abundant metal sites, so that the metal organic framework material has abundant catalytic activity centers; the derivative metal nitrogen carbon material provided by the invention can be used as a cathode oxygen reduction catalyst of a metal-air battery or a fuel battery, has excellent catalytic performance, has extremely high oxygen reduction activity compared with other existing non-noble metal materials, has performance close to that of a commercial platinum carbon catalyst, and is a potential substitute of a noble metal oxygen reduction catalyst.

2. The synthesis method of the metal organic framework material with the new structure is simple, and the needed raw materials are low in cost and wide in source.

3. The invention directly uses the prepared metal organic framework as a precursor to calcine under inert atmosphere, thus obtaining the metal nitrogen-carbon material without other nitrogen sources.

Drawings

FIG. 1 is a schematic diagram of the crystal structure of the Ni-NTA metal-organic framework material obtained in example 1 of the present invention.

FIG. 2 is the X-ray powder diffraction curve and the theoretical simulation curve chart of the Ni-NTA metal-organic framework material obtained in example 1 of the present invention.

FIG. 3 shows SEM pictures (FIG. 3(a)) and TEM pictures (FIG. 3(b)) of NiCo-NTA metal organic framework material obtained in example 4 of the present invention.

FIG. 4 is the X-ray powder diffraction pattern of the Ni-Co metallic nitrogen-carbon catalyst obtained in example 5 of the present invention.

Fig. 5 is a transmission electron micrograph (fig. 5(a)) and a particle size distribution chart (fig. 5(b)) of the nickel-cobalt metal carbonitride catalyst obtained in example 5 of the present invention.

FIG. 6 is a graph showing the oxygen reduction performance of the Ni-Co metallic nitrogen-carbon catalyst and the commercial Pt-carbon catalyst obtained in example 5 of the present invention.

Fig. 7 is a stability test experimental curve of the nickel-cobalt metal nitrocarbon catalyst and the commercial platinum-carbon catalyst obtained in example 5 of the present invention.

Detailed Description

The present invention will be further illustrated with reference to the following specific examples, but the present invention is not limited to the following examples.

The processes described in the examples below are conventional unless otherwise specified, and the starting materials are commercially available from the public unless otherwise specified.

Example 1

0.60g of nitrilotriacetic acid (NTA) was mixed with 0.77g of nickel chloride (NiCl)₂) And (2) placing the mixture into a reaction kettle, adding 30mL of water and 10mL of isopropanol, sealing, placing the mixture into an oven, heating to 180 ℃ for reaction for 6 hours, then centrifugally filtering the obtained product, washing with water, centrifuging, and drying in vacuum at 60 ℃ to obtain the Ni-NTA metal organic framework material.

The crystal structure of the Ni-NTA novel metal organic framework material prepared in this example is shown in fig. 1, and the detailed crystallographic parameters are shown as follows:

the Ni-NTA metal organic framework material obtained in the embodiment has a linear morphology.

The X-ray powder diffraction profile and the theoretical simulation curve of the Ni-NTA metal-organic framework material obtained in this example are shown in fig. 2, which shows that the XRD diffraction data of Ni-NTA obtained in this example and XRD diffraction data that can be theoretically simulated correspond to the crystal structure.

Example 2

This example prepares a Ni-NTA metal organic framework material in the same manner as in example 1, except that: the inorganic metal salt nickel chloride in example 1 was changed to nickel nitrate. The complex obtained in this example is still Ni-NTA metal organic framework material, and the crystal structure is also the same as that of example 1.

Example 3

This example prepares a Ni-NTA metal organic framework material in the same manner as in example 1, except that: the inorganic metal salt nickel chloride in example 1 was changed to nickel sulfate. The complex obtained in this example is still Ni-NTA metal organic framework material, and the crystal structure is also the same as that of example 1.

Example 4

0.60g of nitrilotriacetic acid (NTA) was mixed with 0.78g of nickel chlorideAnd cobalt chloride (NiCl)₂With CoCl₂The mass ratio of the components is 1:1), the components are placed in a reaction kettle, 30mL of water and 10mL of isopropanol are added, the mixture is sealed and placed in an oven, the temperature is increased to 180 ℃ for reaction for 6 hours, then the product obtained by centrifugal filtration is washed with water and centrifuged, and vacuum drying is carried out at 60 ℃ to obtain the NiCo-NTA metal organic framework material, wherein the crystal structure of the NiCo-NTA metal organic framework material is the same as that of the embodiment 1.

The scanning electron microscope photograph and the transmission electron microscope photograph of the NiCo-NTA metal organic framework material prepared in this example are shown in fig. 3, wherein fig. 3(a) is the scanning electron microscope photograph and fig. 3(b) is the transmission electron microscope photograph. As can be seen, the material obtained in this example has a one-dimensional linear morphology with a radius of about 250 nm.

Example 5

Taking 0.40g of NiCo-NTA prepared in the example 4, placing the NiCo-NTA in a crucible, transferring the NiCo-NTA in a quartz tube of a tube furnace, exhausting air for half an hour by using nitrogen, heating the NiCo-NTA to 700 ℃, and carrying out heat preservation and calcination for 2 hours under the protection of the nitrogen to obtain a heat-treated product; and collecting the heat treatment product, washing with water, centrifuging and drying at 60 ℃ in vacuum to obtain the derivative nickel-cobalt metal nitrogen-carbon catalyst.

Fig. 4 is an X-ray powder diffraction curve of the ni-co metal nitrocarbon catalyst prepared in this example, which shows that the ni-co metal and carbon are contained in the catalyst.

The transmission electron micrograph and the statistical distribution of the particle size of the nickel-cobalt metal nitrogen-carbon catalyst prepared in this example are shown in fig. 5, wherein fig. 5(a) is the transmission electron micrograph and fig. 5(b) is the statistical distribution of the particle size in the transmission electron microscope. As can be seen from the figure, the nickel-cobalt metal nitrogen-carbon catalyst prepared in this embodiment is in the shape of a one-dimensional rod, and the nickel-cobalt metal particles are uniformly distributed on the surface at a high density, and meanwhile, as can be seen from the figure b, the average statistical particle size of the nickel-cobalt metal particles is about 9.3 nm.

The oxygen reduction experimental curves of the nickel-cobalt metallic nitrogen-carbon catalyst prepared in this example and the commercially used platinum-carbon catalyst are shown in fig. 6, and the specific experimental method is as follows: oxygen reduction experiments were performed using a rotating disk electrode rotating at 1600rpm in 0.1mol/L potassium hydroxide solution at a sweep rate of 10 mV/s. The comparative commercially used platinum-carbon catalyst was a commercial platinum-carbon catalyst having a platinum content of 20% by weight purchased from Johnson-Matthey (Shanghai) catalyst Co. As can be seen, the oxygen reduction activity of the nickel cobalt metal nitrocarbon catalyst is close to that of the commercial platinum carbon catalyst.

The experimental curves of the stability tests of the nickel-cobalt metallic nitrogen-carbon catalyst prepared in this example and the platinum-carbon catalyst used commercially are shown in fig. 7. The specific experimental method comprises the following steps: chronoamperometric curves were measured with a rotating disk electrode at 1600rpm in 0.1mol/L potassium hydroxide solution saturated with oxygen, at a constant potential of 0.765V (vs. a standard hydrogen electrode) and for 20000 s. Comparing the two curves, it can be seen that: after 20000s of 0.765V (relative to a standard hydrogen electrode) constant potential aging, the reaction current of the nickel-cobalt metal nitrogen-carbon catalyst prepared in the example is 91.3% of the initial reaction current after 20000s, which is higher than 58.5% of that of the commercial platinum-carbon catalyst, which indicates that the non-noble metal oxygen reduction catalyst prepared in the example has better stability than the commercial platinum-carbon catalyst.

Example 6

This example prepared a nickel cobalt metallic nitrogen carbon catalyst in the same manner as in example 5, except that: the nitrogen was replaced by argon. The catalyst obtained in this example was subjected to an oxygen reduction curve in a 0.1mol/L potassium hydroxide solution in the same manner as in example 5 to obtain a half-wave potential equivalent to that of the catalyst of example 5.

Example 7

This example prepared a nickel cobalt metallic nitrogen carbon catalyst in the same manner as in example 5, except that: the temperature of calcination was changed to 800 ℃. The catalyst obtained in this example was subjected to an oxygen reduction curve in a 0.1mol/L potassium hydroxide solution in the same manner as in example 5 to obtain a half-wave potential equivalent to that of the catalyst of example 5.

The present invention is not limited to the above exemplary embodiments, and any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.