Preparation method and application of metalloporphyrin and metal disulfide coupled porous organic polymer
By preparing porous organic polymers coupled with metal porphyrins and metal disulfides, the problems of difficult activation and low product selectivity of existing electrocatalysts in CO2 reduction reactions were solved, efficient and stable CO2 reduction performance and product selectivity were achieved, and a platform for structure-activity relationship research was provided.
Patent Information
- Application Number
- CN202510859018.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-25
- Publication Date
- 2025-09-16
AI Technical Summary
Existing electrocatalysts have difficulties in activation, low product selectivity, poor catalyst stability and difficulty in achieving high efficiency and stability in CO2 reduction reactions. The lack of a systematic structure-activity relationship research platform has hindered the development of electrocatalytic CO2 reduction technology.
A porous organic polymer with a bimetallic center was prepared by coupling metalloporphyrin and metal disulfide through Knoevenagel condensation reaction. Its unique electronic structure and porosity were utilized to promote CO2 adsorption and diffusion, and the catalytic efficiency was improved by regulating the active sites.
It achieves efficient CO2 reduction activation and product selectivity, improves the stability and conductivity of the catalyst, provides a platform for structure-activity relationship research, and enhances the electrocatalytic CO2 reduction performance.
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Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of porous organic polymer-based electrocatalytic materials and their electrocatalytic CO2 reduction applications, and specifically relates to a preparation method and application of a porous organic polymer coupled with metal porphyrin and metal disulfide. Background Art
[0002] Electrocatalytic CO2 reduction technology, driven by clean electricity, converts CO2 into high-value-added chemicals. This technology is strategically important for achieving carbon resource recycling and renewable energy storage, and provides important technical support for achieving my country's "dual carbon" goals. However, the industrialization of this technology faces the following challenges: First, the high thermodynamic stability and kinetic inertness of CO2 molecules make CO2 activation difficult; second, the electrocatalytic CO2 reduction reaction involves multiple elementary reactions and multiple reduction pathways. The standard electrode potentials of different electroreduction pathways differ slightly, and hydrogen evolution reactions occur in the aqueous phase, resulting in low selectivity for carbon-containing products; third, the adsorption strength of key intermediates and catalytic active sites affects catalytic selectivity, but existing catalysts are difficult to precisely control.
[0003] Existing electrocatalyst systems face numerous technical bottlenecks. On the one hand, traditional metal-based materials are limited by surface reconstruction phenomena, resulting in poor active site stability. On the other hand, molecular catalysts exhibit poor conductivity and a tendency to aggregate, causing their catalytic efficiency to decay over time. Furthermore, most reported materials struggle to simultaneously achieve high product selectivity and long-term stability, and lack a systematic structure-activity relationship research platform, significantly hindering the development of electrocatalytic CO2 reduction technology.
[0004] In recent years, porous organic polymers have become a research hotspot due to their unique advantages. Their high surface area and porosity effectively promote the adsorption and diffusion of CO2, thereby improving the contact efficiency at the reaction interface. Furthermore, ligand design can be used to manipulate the electronic structure of active sites and optimize catalytic pathways. Furthermore, the corrosion resistance and thermal stability of their organic frameworks surpass those of metal-based materials, endowing porous organic polymers with excellent catalytic stability.
[0005] In view of the above situation, it is necessary to provide a method for preparing a porous organic polymer coupled with metal porphyrin and metal disulfide. The porous organic polymer prepared by this method can be applied to electrocatalytic CO2 reduction technology to break through the technical bottleneck of the existing electrocatalyst system and promote the further development of this technology. Summary of the Invention
[0006] The present invention aims to provide a method for preparing a porous organic polymer coupled with a metalloporphyrin and a metal disulfide, and its application. The method is simple to operate, and the prepared metalloporphyrin-metal disulfide-based porous organic polymer exhibits excellent electrocatalytic CO2 reduction activity in a 0.5M KHCO3 solution.
[0007] To achieve the above object, the technical solutions adopted by the present invention are as follows:
[0008] The first aspect of the present invention provides a method for preparing a porous organic polymer coupled with metalloporphyrin and metal disulfide, comprising the following steps:
[0009] (1) adding metalloporphyrin and metal disulfide into a solvent and dissolving them;
[0010] Wherein, the metalloporphyrin is 5,10,15,20-tetrakis(4-formylphenyl)porphyrin metal (MPor); the metal dithiolene is a metal dithiolene derivative containing phenylacetonitrile (MS4);
[0011] (2) The reaction system is subjected to a freeze-vacuum-thaw cycle and then reacted to completion under sealed conditions;
[0012] (3) The product is filtered, washed, and then extracted to obtain a porous organic polymer coupled with metal porphyrin and metal disulfide.
[0013] The metal porphyrin is 5,10,15,20-tetrakis(4-formylphenyl)porphyrin cobalt (CoPor) or 5,10,15,20-tetrakis(4-formylphenyl)porphyrin nickel (NiPor); the metal disulfide is a nickel (II) disulfide derivative containing phenylacetonitrile, recorded as NiS4.
[0014] Furthermore, in step (1), 9-20 mg of CoPor and 10-25 mg of NiS4 are added to each milliliter of solvent.
[0015] Furthermore, in step (1), the solvent is a 1,2-dichlorobenzene-sodium ethanol mixed solvent.
[0016] Furthermore, in step (1), the volume ratio of 1,2-dichlorobenzene-sodium ethanolate in the 1,2-dichlorobenzene-sodium ethanolate mixed solvent is 10:1.
[0017] Furthermore, the freeze-pump-thaw cycle in step (2) is as follows: freezing the product with liquid nitrogen, evacuating the product, and thawing the product with nitrogen.
[0018] Furthermore, in step (2), the reaction temperature is 70-150° C., and the reaction time is 48-120 hours.
[0019] Furthermore, in step (3), the product is washed with dichloromethane and methanol, and Soxhlet extracted with tetrahydrofuran and dichloromethane for 24-72 hours, and finally vacuum dried to obtain a porous organic polymer coupled with metalloporphyrin and metal disulfide.
[0020] The present invention uses a Knoevenagel condensation reaction to polymerize 5,10,15,20-tetrakis(4-formylphenyl)porphyrin cobalt with a metal dithiolene derivative containing phenylacetonitrile. The synthetic route of the porous organic polymer is as follows:
[0021]
[0022] Furthermore, the structure of the porous organic polymer coupled with metalloporphyrin and metal disulfide is that the metalloporphyrin and metal disulfide units are connected by a carbon-carbon double bond. Compared with other polymer analogs, the dinuclear single-atom catalytic sites of this porous organic polymer have different coordination environments. The electronic interaction between the two metal centers improves CO2 adsorption activation, thereby enhancing the electrocatalytic CO2 reduction activity.
[0023] A second aspect of the present invention provides an application method, which uses the porous organic polymer coupled with the metalloporphyrin and metal disulfide, and comprises the following steps:
[0024] A mixture of porous organic polymers coupled with metal porphyrin and metal disulfide and carbon nanotubes is added to a Nafion ethanol solution, ultrasonically dispersed to obtain a uniform suspension, and then evenly dropped onto a carbon cloth. After drying, it is used as a working electrode, with Ag / AgCl as a reference electrode and a graphite rod as a counter electrode, and can be used as a CO2 reduction electrocatalytic material.
[0025] Furthermore, in the application method, the mass ratio of the porous organic polymer coupled with metal porphyrin and metal disulfide to the carbon nanotubes is 4:1.
[0026] Furthermore, the concentration of the Nafion ethanol solution is 0.05 wt%.
[0027] Compared with existing electrocatalytic materials, the porous organic polymer prepared by the present invention has the following advantages and effects:
[0028] The resulting porous organic polymer coupled with metal porphyrin and metal disulfide achieves the controllable synthesis of bimetallic single atom (MN4 and MS4) catalysts with different coordination environments. The introduction of highly conductive metal disulfide improves the electron transfer rate in the electrocatalytic CO2 reduction reaction. Through the regulation of the bimetallic center, it promotes the adsorption and activation of CO2 on the catalyst surface and the generation of carbon-based intermediates. At the same time, the interaction between the bimetallic single atom sites with different coordination environments promotes the generation of key carbon-based intermediates, inhibits the hydrogen evolution reaction, and thus improves the selectivity of carbon-containing products. A mixture of porous organic polymer and carbon nanotubes (5.0 mg) with a mass ratio of 4:1 was added to a 0.05wt% Nafion ethanol solution (5.0 mL) and ultrasonically dispersed to obtain a uniform suspension. Then 1.0 mL was evenly dropped onto a carbon cloth and, after drying, used as a working electrode, with Ag / AgCl as a reference electrode and a graphite rod as a counter electrode. Experimental results show that the bimetallic center porous organic polymer has higher electrocatalytic CO2 reduction performance than the monomer. The specific advantages are as follows:
[0029] 1) Knoevenagel condensation reaction, porous organic polymers coupled with metalloporphyrins and metal disulfide, where the metalloporphyrins and metal disulfide are connected by carbon-carbon double bonds and have good stability;
[0030] 2) The porous organic polymer exhibited good electrocatalytic CO2 reduction performance in 0.5M KHCO3;
[0031] 3) The controllable construction of porous organic polymers containing binuclear single-atom sites with different coordination environments was achieved by using metalloporphyrins and metal disulfides.
[0032] The readily tunable metal center of the metalloporphyrins of the present invention allows for easy adjustment of electrocatalytic activity at the molecular level. Leveraging the structural diversity of metalloporphyrin-based porous organic polymers and utilizing functional ligands, the synthesis of pre-designed materials provides a promising platform for the development of highly efficient CO2 reduction electrocatalysts, the exploration of structure-activity relationships, and the study of their reaction mechanisms. Metallodisulfides are organic sulfur-rich compounds formed by the coordination of disulfide bidentate ligands with transition metals. They contain metal-sulfur (MS4) single-atom sites and exhibit excellent redox properties and electrical conductivity. BRIEF DESCRIPTION OF THE DRAWINGS
[0033] Figure 1 The structure of the porous polymer (MPor-NiS4) prepared by the present invention;
[0034] Figure 2 This is a diagram of the Faraday efficiency of the electrocatalytic CO2 reduction of the porous polymer (CoPor-NiS4) prepared in the present invention and its comparative sample;
[0035] Figure 3The CO partial current density diagram of the porous polymer (CoPor-NiS4) prepared in the present invention and its comparative sample;
[0036] Figure 4 This is a comparison chart of the Tafel slopes of the porous polymer (CoPor-NiS4) prepared in the present invention and its comparative sample. DETAILED DESCRIPTION
[0037] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, but the present invention is not limited thereto.
[0038] Example 1
[0039] M1Por-NiS4 was synthesized using the aforementioned porous organic polymer synthesis route; M1 = Ni, and the product was labeled NiPor-NiS4. The steps are as follows:
[0040] NiPor (78.59 mg) and NiS4 (93.85 mg) were added to a sealed tube, followed by 4 mL of 1,2-dichlorobenzene. The mixture was sonicated for 30 minutes. Sodium ethoxide (0.4 mL) was then added and sonicated for 30 minutes. After three freeze-vacuum-thaw cycles, the reaction tube was flame-sealed and reacted at 100°C for 72 hours. The product was filtered, washed with dichloromethane and methanol, and Soxhlet extracted with tetrahydrofuran for 72 hours. Finally, it was dried under vacuum to obtain a porous organic polymer (NiPor-NiS4).
[0041] The freeze-vacuum-thaw cycle method is to freeze the reactants with liquid nitrogen, evacuate for 5 minutes, and thaw with nitrogen. The other embodiments are the same.
[0042] Example 2
[0043] CoPor-NiS4 was synthesized using the aforementioned porous organic polymer synthesis pathway. The steps are as follows:
[0044] CoPor (78.57 mg) and NiS4 (93.85 mg) were added to a sealed tube, followed by 4 mL of 1,2-dichlorobenzene. The mixture was sonicated for 30 minutes. Sodium ethoxide (0.4 mL) was then added and sonicated for 30 minutes. After three freeze-vacuum-thaw cycles, the reaction tube was flame-sealed and reacted at 100°C for 72 hours. The product was filtered, washed with dichloromethane and methanol, and Soxhlet extracted with tetrahydrofuran for 72 hours. Finally, it was dried under vacuum to obtain a porous organic polymer (CoPor-NiS4).
[0045] The freeze-vacuum-thaw cycle method is to freeze the reactants with liquid nitrogen, evacuate for 5 minutes, and thaw with nitrogen. The other embodiments are the same.
[0046] Application Example 1
[0047] A porous organic polymer (CoPor-NiS4) or CoPor and carbon nanotubes (5 mg) with a mass ratio of 4:1 was added to a 0.05 wt% Nafion ethanol solution (5 mL) and ultrasonically dispersed for 30 minutes to obtain a uniform suspension. Then 0.5 mL was evenly dropped onto a 1×1 cm 2 On the carbon cloth, after drying, it was used as the working electrode, Ag / AgCl as the reference electrode, and the graphite rod as the counter electrode. Before the test, nitrogen was passed through the reactor to remove the air. CO2 was introduced into the 0.5M KHCO3 solution at a flow rate of 30sccm and continued for 30min. Subsequently, the flow rate was adjusted to 15sccm, and after 30min of electrolysis at different voltage ranges (-0.3--0.9V vs.RHE), the type and concentration of gas phase products were tested by online gas chromatography, and the Faraday efficiency of the corresponding products was calculated. Figure 3 It can be seen that under the condition of -0.7 V vs. RHE, the CO Faradaic efficiency of CoPor-NiS4 is the highest, which is 91%.
[0048] Application Example 2
[0049] 4 mg of CoPor-NiS4 was added to 0.05 wt% Nafion ethanol solution (4 mL) and ultrasonically dispersed for 30 minutes to obtain a uniform suspension. Then 0.5 mL was evenly dropped onto a 1×1 cm 2 A carbon cloth was dried and used as the working electrode, Ag / AgCl as the reference electrode, and a graphite rod as the counter electrode. Before testing, nitrogen was purged from the reactor to remove air. CO2 was introduced into a 0.5M KHCO3 solution at a flow rate of 30 sccm for 30 minutes. Subsequently, the flow rate was adjusted to 15 sccm. After 30 minutes of electrolysis at different voltages (-0.3 to -0.9 V vs. RHE), the gaseous product types and concentrations were measured using an online gas chromatograph. The catalyst exhibited a maximum CO Faradaic efficiency of 78% at -0.7 V vs. RHE.
[0050] Application Example 3
[0051] A porous organic polymer (NiPor-NiS4) and carbon nanotubes (5 mg) with a mass ratio of 4:1 were added to a 0.05 wt% Nafion ethanol solution (5 mL) and ultrasonically dispersed for 30 minutes to obtain a uniform suspension. Then 0.5 mL was evenly dropped onto a 1×1 cm 2After drying, a carbon cloth was used as the working electrode, Ag / AgCl as the reference electrode, and a graphite rod as the counter electrode. Before testing, nitrogen was purged from the reactor to remove air. CO2 was introduced into a 0.5M KHCO3 solution at a flow rate of 30 sccm for 30 minutes. Subsequently, the flow rate was adjusted to 15 sccm. After 30 minutes of electrolysis at different voltages (-0.3 to -0.9 V vs. RHE), the gaseous product types and concentrations were measured using an online gas chromatograph. The catalyst demonstrated a maximum CO Faradaic efficiency of 69% at -0.8 V vs. RHE.
[0052] The above application examples show that the CoPor-NiS4 porous polymer can be used for the electrocatalytic CO2 reduction reaction in CO2-saturated 0.5M KHCO3. Figure 2 It can be seen that the addition of carbon nanotubes as a conductive additive can significantly enhance the CO2 electroreduction performance of the CoPor-NiS4 catalyst. This may be because the addition of carbon nanotubes accelerates the conductivity of the catalyst, which is beneficial to the multi-electron transfer in the CO2 electroreduction reaction, thereby enhancing the CO2 electroreduction performance. Figure 2 and Figure 3 As shown in the figure, the CoPor-NiS4 porous polymer has a higher CO Faraday efficiency than other porous polymers under the same conditions, indicating that CoPor-NiS4 with different coordination environments of CoN4 and NiS4 sites has better CO2 adsorption and activation ability and a lower energy barrier for the formation of *COOH intermediates, thus giving it enhanced performance in the electrocatalytic reduction of CO2 to CO. Figure 4 It can be seen that the CoPor-NiS4 porous polymer has a smaller Tafel slope, indicating that the diatomic double atoms with different coordination environments are beneficial to enhancing the kinetics of the electrocatalytic CO2 reduction to CO. These results show that the CoPor-NiS4 porous polymer electrocatalyst prepared by the present invention can electroreducing CO2 to CO and has good application prospects in electrocatalytic CO2 reduction.
[0053] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent replacements and improvements made by any technician familiar with this technical field within the technical scope disclosed by the present invention should be included in the scope of protection of the invention.
Claims
1. A method for preparing a porous organic polymer coupled with metalloporphyrin and metal disulfide, characterized in that: The following steps are involved: (1) adding metalloporphyrin and metal disulfide into a solvent and dissolving them; Wherein, the metalloporphyrin is 5,10,15,20-tetrakis(4-formylphenyl)porphyrin metal; the metal dithiolon is a metal dithiolon derivative containing benzyl cyanide; (2) The reaction system is subjected to a freeze-vacuum-thaw cycle and then reacted to completion under sealed conditions; (3) The product is filtered, washed, and then filtered to obtain a porous organic polymer coupled with metalloporphyrin and metal disulfide; The metal porphyrin is 5,10,15,20-tetrakis(4-formylphenyl)porphyrin cobalt (CoPor) or 5,10,15,20-tetrakis(4-formylphenyl)porphyrin nickel (NiPor); the metal disulfide is a disulfide nickel (II) derivative containing benzyl cyanide, recorded as NiS4.
2. The preparation method according to claim 1, wherein: In the step (1), 9-20 mg of CoPor and 10-25 mg of NiS4 are added to each milliliter of solvent.
3. The preparation method according to claim 1, wherein: In the step (1), the solvent is a 1,2-dichlorobenzene-sodium ethanol mixed solvent.
4. The preparation method according to claim 3, wherein: In the step (1), the solvent is a 1,2-dichlorobenzene-sodium ethanol mixed solvent in a volume ratio of 10:
1.
5. The preparation method according to claim 1, wherein: In the step (2), the reaction temperature is 70-150° C., and the reaction time is 48-120 hours.
6. The preparation method according to claim 1, wherein: In the step (2), the freeze-vacuum-thaw cycle method is: freezing the reactants with liquid nitrogen, evacuating the reactants, and thawing them with nitrogen.
7. The preparation method according to claim 1, wherein: In the step (3), the product is washed with dichloromethane and methanol, and extracted with tetrahydrofuran and dichloromethane for 24-72 hours, and finally dried in vacuum to obtain a porous organic polymer coupled with metalloporphyrin and metal disulfide.
8. The preparation method according to any one of claims 1 to 7, characterized in that: The structure of the porous organic polymer coupled with metal porphyrin and metal disulfide is that the metal porphyrin and metal disulfide units are connected through a carbon-carbon double bond.
9. An application method, characterized in that: It uses the porous organic polymer coupled with metal porphyrin and metal disulfide as described in claim 8, adds the mixture of the porous organic polymer and carbon nanotubes into Nafion ethanol solution, ultrasonically disperses to obtain a uniform suspension, and then evenly drops it onto carbon cloth. After drying, it is used as a working electrode, Ag / AgCl is used as a reference electrode, and a graphite rod is used as a counter electrode, which can be used as a CO2 reduction electrocatalytic material.
10. The application method according to claim 9, characterized in that: In the application method, the mass ratio of the porous organic polymer coupled with metal porphyrin and metal disulfide to the carbon nanotube is 4:1.