阅读说明：本技术 钴-金属有机框架材料及其制备方法和应用 (Cobalt-metal organic framework material and preparation method and application thereof ) 是由 季长春 韩素军 杨光 张东星 尹丽 于 2019-12-04 设计创作，主要内容包括：本发明公开了一种钴-金属有机框架材料及其制备方法和应用,该钴-金属有机框架材料的分子式为{[Co(L)(H<Sub>2</Sub>O)<Sub>2</Sub>]·CHO<Sub>2</Sub>·1.5H<Sub>2</Sub>O}<Sub>n</Sub>,其中,L<Sup>-</Sup>为去质子化的3′,5′-二(4-吡啶基)-[1,1′-联苯]-4-羧酸,n为正整数,CHO<Sub>2</Sub>表示脱质子的甲酸,1.5H<Sub>2</Sub>O为未参与配位的水。该钴-金属有机框架材料具有优异的光催化性能和热稳定性,同时该制备方法具有操作简便、重现性好和条件温和的特点,进而使得该钴-金属有机框架材料能够大范围地应用于有机染料的光催化降解。(The invention discloses a cobalt-metal organic framework material and a preparation method and application thereof, wherein the molecular formula of the cobalt-metal organic framework material is { [ Co (L) (H) 2 O) 2 ]·CHO 2 ·1.5H 2 O} n Wherein L is ‑ Is deprotonated 3 ', 5 ' -bis (4-pyridyl) - [1,1 ' -biphenyl]-4-carboxylic acid, n is a positive integer, CHO 2 Represents deprotonated formic acid, 1.5H 2 O is water which does not participate in coordination. The cobalt-goldThe cobalt-metal organic framework material has the characteristics of excellent photocatalytic performance and thermal stability, and meanwhile, the preparation method has the characteristics of simplicity and convenience in operation, good reproducibility and mild conditions, so that the cobalt-metal organic framework material can be widely applied to photocatalytic degradation of organic dyes.)

1. The cobalt-metal organic framework material is characterized in that the molecular formula of the cobalt-metal organic framework material is { [ Co (L) (H)₂O)₂]·CHO₂·1.5H₂O}_nWherein L is^-Is deprotonated 3 ', 5 ' -bis (4-pyridyl) - [1,1 ' -biphenyl]-4-carboxylic acid, n is a positive integer, CHO₂Represents deprotonated formic acid, 1.5H₂O is water which does not participate in coordination.

2. The cobalt-metal organic framework material of claim 1, wherein there is a coordination environment of cobalt ions present in the cobalt-metal organic framework material, labeled Co 1; the Co1 is in a distorted octahedral configuration, with each Co1 coordinated with four oxygen atoms and two nitrogen atoms, where the two oxygen atoms are from the same L^-Carboxylate radical in ligand, and other two oxygen atoms from coordinated H₂In O, the two nitrogen atoms belong to two L^-The nitrogen atom of the pyridine ring of the ligand.

3. The cobalt-metal organic framework material of claim 1, wherein the cobalt-metal organic framework material belongs to the monoclinic system, I2/c space group, and the unit cell parameters are respectively:

4. a method of preparing a cobalt-metal organic framework material as claimed in any one of claims 1 to 3, comprising: a cobalt source, 3 ', 5 ' -bis (4-pyridyl) - [1,1 ' -biphenyl ] -4-carboxylic acid, is subjected to a solvothermal reaction in a solvent containing DMF.

5. The production method according to claim 1, wherein the solvothermal reaction satisfies the following condition: the reaction temperature is 60-80 ℃, and the reaction time is 48-72 h.

6. The process according to claim 1, wherein the molar ratio of the cobalt source, 3 ', 5 ' -bis (4-pyridyl) - [1,1 ' -biphenyl ] -4-carboxylic acid is 10: 0.5-3.

7. The preparation method according to claim 1, wherein the solvent consists of DMF, water and acetonitrile in a volume ratio of 1-3: 2-4: 1

Preferably, the dosage ratio of the cobalt source to the solvent is 0.1 mmol: 4-8 mL.

8. The method of any one of claims 4-7, wherein the cobalt source is selected from Co (NO)₃)₂·6H₂O、Co(CH₃COO)₂·4H₂O、CoSO₄·7H₂O and CoCl₂·6H₂At least one of O;

preferably, before the solvothermal reaction, the preparation method further comprises: subjecting the raw materials to ultrasonic vibration for 3-5 min;

more preferably, after the solvothermal reaction, the preparation method further comprises: and (3) cooling the system to 15-25 ℃, carrying out solid-liquid separation, washing the solid, and naturally drying to obtain the cobalt-metal organic framework material.

9. Use of a cobalt-metal organic framework material according to any of claims 1 to 3 for photocatalytic degradation of organic dyes.

10. Use according to claim 9, wherein the step of photocatalytically degrading the organic dye is: firstly, mixing a dye, a cobalt-metal organic framework material and a solvent for 0.5-1h under a dark condition, and then performing degradation reaction for 1-3h under ultraviolet light;

preferably, the dosage ratio of the dye, the cobalt-metal organic framework material and the solvent is 0.3 mg: 5-15 mg: 30-50 mL;

more preferably, the dye is at least one of rhodamine B, methylene blue, and methyl orange.

Technical Field

The invention relates to an organic framework material, in particular to a cobalt-metal organic framework material and a preparation method and application thereof.

Background

Metal-Organic Frameworks (MOFs) belong to coordination polymers, and are crystalline compounds with intramolecular gaps and periodic network structures formed by self-assembly of central Metal atoms/ions (clusters) and ligand molecules. The MOFs have rich structures, generally have structures such as zero-dimensional point, one-dimensional chain, two-dimensional layer and three-dimensional network, and the structural diversity is influenced by multiple factors such as temperature, organic ligands, central metal ions and counter ions. At present, MOFs materials are used as photocatalysts, and research on heterogeneous catalytic degradation of pollutants such as organic dyes is still in progress. Therefore, the preparation of the cobalt-metal organic framework material of the invention is necessary.

The degradation of the existing cobalt metal organic framework material to dye is generally photocatalytic degradation, for example, Shi Zhou et al synthesizes a copper-based metal organic framework and degrades 59 percent of methylene blue dye within 2 hours under an ultraviolet lamp, so that the cobalt metal organic framework material has better catalytic activity; the cobalt-based metal organic framework and the manganese-based metal organic framework which have the isomorphic structure are combined by the book of religious problems, and the methylene blue is degraded under an ultraviolet lamp, but the cobalt-based metal organic framework is unstable in water, while the manganese-based metal organic framework has better stability in water, and the degradation rate of the methylene blue after being photocatalyzed for ten hours is 52.5%.

Disclosure of Invention

The invention aims to provide a cobalt-metal organic framework material, a preparation method and application thereof, wherein the cobalt-metal organic framework material has excellent photocatalytic performance and thermal stability, and meanwhile, the preparation method has the characteristics of simplicity and convenience in operation, good reproducibility and mild conditions, so that the cobalt-metal organic framework material can be widely applied to photocatalytic degradation of dyes.

In order to achieve the above object, the present invention provides cobalt-goldBelongs to an organic framework material, the molecular formula of the cobalt-metal organic framework material is { [ Co (L) (H)₂O)₂]·CHO₂·1.5H₂O}_nWherein L is^-Is deprotonated 3 ', 5 ' -bis (4-pyridyl) - [1,1 ' -biphenyl]-4-carboxylic acid, n is a positive integer, CHO₂Represents deprotonated formic acid (obtained by hydrolysis of DMF), 1.5H₂O is water which does not participate in coordination.

The invention also provides a preparation method of the cobalt-metal organic framework material, which is characterized by comprising the following steps: a cobalt source, 3 ', 5 ' -bis (4-pyridyl) - [1,1 ' -biphenyl ] -4-carboxylic acid, is subjected to a solvothermal reaction in a solvent containing DMF.

The invention provides an application of the cobalt-metal organic framework material in photocatalytic degradation of organic dyes.

In the technical scheme, the invention uses 3 ', 5 ' -di (4-pyridyl) - [1,1 ' -biphenyl]4-carboxylic acid as ligand, and carrying out solvothermal reaction with cobalt source to obtain the cobalt-metal organic framework material { [ Co (L) (H)₂O)₂]·CHO₂·1.5H₂O}_n(ii) a The cobalt-metal organic framework material has excellent photocatalytic performance and is mainly prepared by O through photo-generated electrons in a reaction system₂The electron trapping agent is combined to form superoxide anion, the left hole directly oxidizes water or hydroxyl ion in the system to form hydroxyl radical, and the superoxide anion and the hydroxyl radical have strong oxidability and can oxidize most organic matters to a final product H₂O and CO₂Even some inorganic matters can be thoroughly decomposed, so that the cobalt-metal organic framework material can be used for degrading organic dye by photocatalysis; meanwhile, the cobalt-metal organic framework material has excellent thermal stability, so that the cobalt-metal organic framework material has wide application prospect.

Additional features and advantages of the invention will be set forth in the detailed description which follows.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:

FIG. 1 is an ellipsoid plot of the complex of example 1 (ellipsoid probability 30%, hydrogen atoms and lattice molecules omitted for clarity; symmetrical operation: #1 ═ 2-x, y, 2.5-z; #2 ═ 0.5+ x, -0.5+ y,0.5+ z; #3 ═ 1.5-x, -0.5+ y, 2-z; #4 ═ 1-x, y, 1.5-z; # 5; -0.5+ x,0.5+ y, -0.5+ z; # 6; # 1.5-x,0.5+ y, 2-z; # 7; # 0.5+ x,0.5+ y,0.5+ z; # 8; # 2.5-x,0.5+ y, 3-z; # 1; (x, y + z); (1, 1+ z);

FIG. 2 is a schematic diagram of the complex in example 1 in the bc plane (H atom and lattice molecule are omitted for clarity);

FIG. 3 is a schematic diagram of the three-dimensional structure of the complex in example 1 (H atoms and molecules of the crystal lattice are omitted for clarity);

FIG. 4 is a thermogravimetric analysis of the complex of example 1;

FIG. 5a is a graph of the UV-VIS absorption spectrum of the complex of example 1;

FIG. 5b is a graph showing the kinetics of UV-visible absorption of the complex of example 1;

FIG. 5C shows UV-visible absorption of the complex of example 1 for ln (C)_t/C₀) Linear fitting relation graph is carried out on the curve about Kt;

FIG. 5d is a graph of the conversion of the complex to rhodamine B in example 1;

FIG. 6 is an X-ray powder diffraction pattern of crystals of the complex in example 1.

Detailed Description

The following describes in detail specific embodiments of the present invention. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.

The invention provides a cobalt-metal organic framework material, and the molecular formula of the cobalt-metal organic framework material is { [ Co (L) (H)₂O)₂]·CHO₂·1.5H₂O}_nWherein L is^-Is deprotonated 3 ', 5 ' -bis (4-pyridyl) - [1,1 ' -biphenyl]-4-carboxylic acid, n is a positive integer, CHO₂Represents deprotonated formic acid, 1.5H, produced by hydrolysis of DMF₂O is water which does not participate in coordination.

In the present invention, the specific coordination mode and structure of cobalt ions in the cobalt-metal organic framework material can be selected in a wide range, but in order to make it have more excellent photocatalytic performance and thermal stability, it is preferable that cobalt ions of a coordination environment, labeled as Co1, exist in the cobalt-metal organic framework material; the Co1 is in a distorted octahedral configuration, with each Co1 coordinated with four oxygen atoms and two nitrogen atoms, where the two oxygen atoms are from the same L^-Carboxylate radical in ligand, and other two oxygen atoms from coordinated H₂In O, the two nitrogen atoms are each independently derived from two L^-The nitrogen atom of the pyridine ring of the ligand.

In the present invention, the crystal form of the cobalt-metal organic framework material can be selected in a wide range, but in order to make it have more excellent photocatalytic performance and thermal stability, preferably, the cobalt-metal organic framework material belongs to the monoclinic system, I2/c space group, and the unit cell parameters are respectively:

α＝90.00°，β＝96.09(5)°，γ＝90.00°。

the invention also provides a preparation method of the cobalt-metal organic framework material, which is characterized by comprising the following steps: a cobalt source, 3 ', 5 ' -bis (4-pyridyl) - [1,1 ' -biphenyl ] -4-carboxylic acid, is subjected to a solvothermal reaction in a solvent containing DMF.

In the above-mentioned production method, the specific conditions of the solvothermal reaction may be selected within a wide range, but in order to further improve the reaction rate and the yield of the cobalt-metal organic framework material, it is preferable that the solvothermal reaction satisfies the following conditions: the reaction temperature is 60-80 ℃, and the reaction time is 48-72 h.

In the above-mentioned production method, the amount of each material to be used may be selected within a wide range, but in order to further improve the reaction rate and the yield of the cobalt-metal organic framework material, it is preferable that the molar ratio of the cobalt source, 3 ', 5 ' -bis (4-pyridyl) - [1,1 ' -biphenyl ] -4-carboxylic acid is 10: 0.5-3.

In the above preparation method, the specific composition and compounding ratio of the solvent may be selected within a wide range, but in order to further improve the reaction rate and yield of the cobalt-metal organic framework material, it is preferable that the solvent consists of DMF, water and acetonitrile in a volume ratio of 1-3: 2-4: 1.

in the above-mentioned production method, the amount of the solvent to be used may be selected within a wide range, but in order to further improve the reaction rate and the yield of the cobalt-metal organic framework material, it is preferable that the ratio of the amount of the cobalt source to the amount of the solvent to be used is 0.1 mmol: 4-8 mL.

In the present invention, the specific kind of the cobalt source may be selected within a wide range, but from the viewpoint of solubility and cost, it is preferable that the cobalt source is selected from Co (NO)₃)₂·6H₂O、Co(CH₃COO)₂·4H₂O、CoSO₄·7H₂O and CoCl₂·6H₂At least one of O.

In the present invention, in order to further allow sufficient contact between the raw materials and further improve the reaction rate and the yield of the cobalt-metal organic framework material, preferably, the preparation method further comprises, before the solvothermal reaction: subjecting the raw materials to ultrasonic oscillation for 3-5 min.

In the present invention, the post-treatment after the solvothermal reaction may be performed in multiple ways, such as direct filtration, centrifugation, or natural volatilization of the solvent, but in order to shorten the reaction flow and improve the purity of the product, it is preferable that the preparation method further comprises, after the solvothermal reaction: and (3) cooling the system, cooling to room temperature, carrying out solid-liquid separation, washing the solid with mother liquor, and naturally drying the solid to obtain the cobalt-metal organic framework material.

The invention provides an application of the cobalt-metal organic framework material in photocatalytic degradation of organic dyes.

In the above application, the step of photocatalytically degrading the organic dye may be selected within a wide range, but in order to further improve the efficiency of photocatalytic degradation, it is preferable that the step of photocatalytically degrading the organic dye is: firstly, mixing the dye, the cobalt-metal organic framework material and the solvent for 0.5 to 1 hour under the dark condition, and then carrying out degradation reaction for 1 to 3 hours under ultraviolet light.

In the above application, the ratio of the raw materials in the photocatalytic degradation can be selected in a wide range, but in order to further improve the efficiency of the photocatalytic degradation, the ratio of the amount of the dye, the cobalt-metal organic framework material, and the solvent is preferably 0.3 mg: 5-15 mg: 30-50 mL.

In the above application, the kind of the dye may be selected in a wide range, but preferably, the dye is at least one of rhodamine B, methylene blue, and methyl orange in view of the efficiency of photocatalysis and the degree of prevalence of the dye.

The present invention will be described in detail below by way of examples.