Preparation method of cobalt-calcium coordination polymer and photocatalytic hydrogen production application of cobalt-calcium coordination polymer
By synthesizing the cobalt-calcium coordination polymer material CoCa(2-sina)2 as a catalyst, the problem of insufficient catalytic hydrogen production performance of metal-organic framework materials under visible light in the existing technology was solved, and a highly efficient photocatalytic hydrogen production effect was achieved.
Patent Information
- Application Number
- CN202511625262.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2025-08-15
- Filing Date
- 2025-11-07
- Publication Date
- 2026-02-06
AI Technical Summary
In existing technologies, metal-organic framework materials have insufficient performance as catalysts for hydrogen production under visible light, and there is a need to develop materials with higher catalytic activity.
A novel cobalt-calcium coordination polymer material, CoCa(2-sina)2, was synthesized using 2-mercaptoisonicotinic acid and CoCl2·6H2O. This material was then used as a catalyst for hydrogen production through a photocatalytic reaction under the combined action of a photosensitizer and a sacrificial agent.
It achieves excellent catalytic hydrogen production performance under visible light irradiation, improves electron transport performance, and increases photocatalytic hydrogen production efficiency.
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Figure CN121471531A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of materials technology, specifically relating to a method for preparing a cobalt-calcium coordination polymer material and its application in photocatalytic hydrogen production. Background Technology
[0002] Metal-organic frameworks (MOFs) are crystalline materials composed of metal ions or metal clusters and organic ligands. They possess high tunability and diversity, allowing for the manipulation of their structure and properties by adjusting the selection and ratio of metal ions and organic ligands, thereby achieving specific functions. Research on MOF materials involves multiple disciplines, such as chemistry, materials science, and physics, resulting in a very broad research background. The synthesis of novel metal ions and organic ligands, the design and construction of new MOF materials, and the study of their structure and properties have driven the development and application of MOF materials.
[0003] The novel cobalt-calcium coordination polymer material CoCa(2-sina)2 of this invention has a simple synthesis method, and pure crystals can be obtained through simple washing. Furthermore, as a catalyst, this crystal exhibits excellent hydrogen production performance under visible light irradiation. Summary of the Invention
[0004] The purpose of this invention is to provide a method for preparing a cobalt-calcium coordination polymer material and its application in photocatalytic hydrogen production. This invention prepares a novel cobalt-calcium coordination polymer material, CoCa(2-sina)2, based on 2-mercaptoisonicotinic acid and CoCl2·6H2O. This coordination polymer material exhibits excellent catalytic activity as a catalyst in photocatalytic hydrogen production reactions.
[0005] To achieve the above objectives, the present invention adopts the following technical solution: This invention provides a novel cobalt-calcium coordination polymer material based on 2-mercaptoisonicotinic acid and CoCl2·6H2O, with the chemical formula CoCa(2-sina)2, monoclinic crystal system, space group C2 / c, and cell parameters a = 31.5440(12), b = 5.5342(2), c = 6.9592(3). α = 90°, β = 106.560(4)°, γ = 90°, Z = 4, cell volume V = 1201.36(7) Å 3 The 2-sina ligand is derived from the 2-mercaptoisonicotinic acid ligand in the crystal.
[0006] The preparation method of the cobalt-calcium coordination polymer material is as follows: 2-Mercaptoisonicotinic acid and an alkaline source were first mixed in deionized water and then magnetically stirred for 20 minutes in a polytetrafluoroethylene liner at room temperature to ensure complete dissolution and uniform dispersion. Then, a cobalt source and a calcium source were added to the solution and stirred for 100 minutes. Finally, the mixed solution was sealed in a hydrothermal synthesis reactor and placed in an oven for hydrothermal reaction. After repeated washing with deionized water, the solution was freeze-dried to obtain black crystals.
[0007] Furthermore, in the above preparation method, the molar ratio of 2-mercaptoisonicotinic acid, cobalt source, calcium source and alkali source is 1:0.5:0.5~0.7:2~2.1, the cobalt source is CoCl2·6H2O, the calcium source is Ca(NO3)2·4H2O, the alkali source is KOH, and the total stirring time is 120 min.
[0008] Furthermore, the hydrothermal reaction conditions are as follows: the temperature is increased from 30 ℃ to 210 ℃ at a heating rate of 45 ℃ / h, held at that temperature for 48 h, and then decreased from 210 ℃ to 30 ℃ at a rate of 3.75 ℃ / h.
[0009] The present invention also provides the application of the above-mentioned material CoCa(2-sina)2 in the field of photocatalytic hydrogen production. Specifically, under the combined action of photosensitizer and sacrificial agent, the material is used as a catalyst and irradiated under an 8.75 W LED light to exhibit good catalytic hydrogen production performance.
[0010] Furthermore, the photosensitizer is eosin Y. The sacrificial agent is triethanolamine (TEOA).
[0011] The beneficial effects of this invention are as follows: (1) This invention obtains a novel cobalt-based coordination polymer material CoCa(2-sina)2 through a simple preparation method. Under the combined action of photosensitizer and sacrificial agent, this organometallic coordination polymer material exhibits good catalytic hydrogen production performance under visible light irradiation.
[0012] (2) In this invention, 2-mercaptoisonicotinic acid (2-sina) is selected as the ligand. This ligand has two functional groups: a thiol group and a carboxyl group. The thiol group can promote interlayer charge delocalization, which has the characteristic of improving the conductivity of MOFs. In the structure of the catalyst CoCa(2-sina)2, the cobalt atom coordinates with the sulfur atom at the thiol end of the ligand and the nitrogen atom on the pyridine ring to construct a CoS chain, forming a CoS layer and enhancing the conductivity of the material. Based on the advantages of this structure, the electron transport performance in the photocatalytic reaction process can be improved, thereby enhancing the photocatalytic hydrogen production performance. Attached Figure Description
[0013] Figure 1The diagram shows the coordination structure of the cobalt-based coordination polymer material CoCa(2-sina)2 prepared in Example 1.
[0014] Figure 2 This is a structural diagram of the CoS surface in the cobalt-based coordination polymer material CoCa(2-sina)2 prepared in Example 1.
[0015] Figure 3 This is a diagram showing the coordination environment of Ca atoms in the cobalt-based coordination polymer material CoCa(2-sina)2 prepared in Example 1.
[0016] Figure 4 This is a structural diagram of the CaO surface in the cobalt-based coordination polymer material CoCa(2-sina)2 prepared in Example 1.
[0017] Figure 5 This is a three-dimensional packing diagram of the cobalt-based coordination polymer material CoCa(2-sina)2 prepared in Example 1 along the b-axis.
[0018] Figure 6 The X-ray powder diffraction pattern of the cobalt-calcium coordination polymer material CoCa(2-sina)2 prepared in Example 1 is shown. Simulated is the diffraction pattern obtained by fitting the resolved crystal structure; Experimental is the pattern obtained by X-ray powder diffraction of the sample.
[0019] Figure 7 The photocatalytic hydrogen production performance of the cobalt-calcium coordination polymer material CoCa(2-sina)2 prepared in Example 1 and the coordination polymer material prepared in the comparative example is compared under visible light irradiation.
[0020] Figure 8 The powder X-ray diffraction patterns of the cobalt-calcium coordination polymer material CoCa(2-sina)2 prepared in Example 1 before and after the photocatalytic hydrogen production reaction are shown. Detailed Implementation
[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined as long as they do not conflict with each other.
[0022] Example 1 The hydrothermal method was used to synthesize CoCa(2-sina)2 crystals. The specific steps are as follows: 2-Mercaptoisonicotinic acid, CoCl2·6H2O, Ca(NO3)2·4H2O, and KOH were weighed into a hydrothermal reactor according to a certain molar ratio. 8 mL of deionized water was added, and the mixture was stirred, sealed, and heated. The hydrothermal reaction conditions were as follows: the temperature was increased from 30 ℃ to 210 ℃ at a rate of 45 ℃ / h, held at this temperature for 48 h, and then decreased from 210 ℃ to 30 ℃ at a rate of 3.75 ℃ / h. After the reaction was completed, the mixture was washed with deionized water and then freeze-dried to obtain black crystals. The proportions of each raw material and sample numbers are shown in Table 1. (Adjustments to the proportions of raw materials in Table 1 will not affect the structure and properties of the material).
[0023] Table 1 Synthesis conditions of sample CoCa(2-sina)2
[0024] Single-crystal X-ray diffraction analysis showed that the crystal CoCa(2-sina)2 is a monoclinic crystal with space group C2 / c and cell parameters a = 31.5440(12), b = 5.5342(2), c = 6.9592(3). α = 90°, β = 106.560(4)°, γ =90°, Z = 4, cell volume V = 1201.36(7) Å 3 The 2-sina ligand is derived from the 2-mercaptoisonicotinic acid ligand in the crystal.
[0025] CoCa(2-sina)₂ is composed of Co atoms, Ca atoms, and a 2-mercaptoisonicotinic acid ligand. In the asymmetric unit, the Co atom coordinates with the S and N atoms of the deprotonated 2-mercaptoisonicotinic acid ligand, forming a six-coordinated trans-octahedral configuration (e.g., ...). Figure 1 (As shown). The S atoms exhibit both chelate coordination and bridging coordination modes. Four adjacent Co atoms and four S atoms alternately arrange to form a ring structure, extending infinitely along the a-axis and b-axis directions, forming a two-dimensional CoS surface (as shown). Figure 2 (As shown). The Ca atom coordinates with the carboxyl oxygen atom in the deprotonated 2-mercaptoisonicotinic acid ligand to form a six-coordinate octahedral configuration (as shown). Figure 3 (As shown). Adjacent Ca atoms are connected by two bridging μ2-O2 atoms in a shared-edge manner, and extend along the a-axis to form CaO chains. Adjacent CaO chains are connected by O1 and O2 atoms in the bridging carboxyl groups, and extend along the b-axis to form CaO faces (as shown). Figure 4 As shown). The CoS and CaO surfaces are stacked in an ABAB pattern and extend continuously along the c-axis to form a three-dimensional structure (as shown). Figure 5 (As shown).
[0026] Comparative Example The preparation steps of the comparative crystal differ from those of Example 1 in that 6-mercaptonicotinic acid (6-mna) is used as the ligand. All other steps are the same, and the resulting crystal is [Co3Ca3(6-mna)6(H2O)3]·6H2O crystal.
[0027] Example 2 Photocatalytic hydrogen production performance study: Weigh 10 mg of the crystal sample prepared in Example 1 or the comparative example, and add it to an aqueous solution containing 5% TEOA (sacrificial agent) and 4 mM eosin Y (photosensitizer). Then transfer the solution to a reaction flask and carry out a photocatalytic reaction under 8.75 W LED light irradiation. After 10 h, the photocatalytic hydrogen production performance is as follows: Figure 7 As shown in the figure. The photocatalytic hydrogen production capacity of the CoCa(2-sina)2 crystals prepared in Example 1 reached 308.074 μmol after 10 h, and the photocatalytic hydrogen production efficiency reached 3080.74 μmol·g. -1 ·h -1 The concentration was significantly higher than that of the [Co3Ca3(6-mna)6(H2O)3]·6H2O crystals prepared in the comparative example.
[0028] Example 3 Stability of CoCa(2-sina)2 crystals: After the photocatalytic reaction was completed, the catalyst CoCa(2-sina)2 in the system was separated by centrifugation, washed three times with deionized water and ethanol, and freeze-dried. The powder X-ray diffraction patterns of the samples before and after photocatalysis were compared. Figure 8 As shown, both remained almost unchanged, indicating that the catalyst retains its original structure after the photocatalytic hydrogen production reaction.
[0029] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should be included in the scope of the present invention.
Claims
1. A cobalt-calcium coordination polymer material, characterized in that, The chemical formula of the cobalt-calcium coordination polymer material is CoCa(2-sina)2, monoclinic crystal system, space group C2 / c, and cell parameters a = 31.5440(12), b = 5.5342(2), c = 6.9592(3). α = 90°, β = 106.560(4)°, γ = 90°, Z = 4, cell volume V = 1201.36(7) Å 3 The 2-sina ligand is derived from the 2-mercaptoisonicotinic acid ligand in the crystal.
2. The method for synthesizing the cobalt-calcium coordination polymer material as described in claim 1, characterized in that, By adding 2-mercaptoisonicotinic acid and an alkaline source to 8 mL of deionized water and stirring for 20 min, then adding a cobalt source and a calcium source and stirring for 100 min, the mixed solution was finally loaded into a reaction vessel for hydrothermal reaction. After the reaction was completed, the solution was washed with deionized water and then freeze-dried to obtain black target crystals, namely cobalt-calcium coordination polymer materials.
3. The synthesis method according to claim 2, characterized in that, The molar ratio of 2-mercaptoisonicotinic acid, cobalt source, calcium source and alkali source is 1:0.5:0.5~0.7:2~2.
1.
4. The synthesis method according to claim 2, characterized in that, The cobalt source is CoCl2·6H2O.
5. The synthesis method according to claim 2, characterized in that, The alkali source is KOH.
6. The synthesis method according to claim 2, characterized in that, The calcium source is Ca(NO3)2·4H2O.
7. The synthesis method according to claim 2, characterized in that, The hydrothermal reaction conditions are: heating from 30 ℃ to 210 ℃, holding at that temperature for a period of time, and then cooling down to 30 ℃.
8. The synthesis method according to claim 7, characterized in that, The heating rate is 45 ℃ / h, and the cooling rate is 3.75 ℃ / h.
9. The synthesis method according to claim 7, characterized in that, The heat preservation time is 48 hours.
10. The application of the cobalt-calcium coordination polymer material as described in claim 1 in photocatalytic hydrogen production reaction.