A porous carbon supported copper catalyst and a preparation method and application thereof

Abstract

This invention discloses a porous carbon-supported copper catalyst, its preparation method, and its application, belonging to the field of catalyst preparation technology. The invention uses three-dimensional interconnected ordered porous carbon (NCP) with a large-pore structure as a support, tetraphenylporphyrin copper(II) and tetraphenylporphyrin as nitrogen and copper sources, and KOH or NaOH as activators. An NCP precursor adsorbed with tetraphenylporphyrin copper(II), tetraphenylporphyrin, and an alkaline component is obtained through a two-step adsorption process. This precursor is then pyrolyzed at 600-900℃ under nitrogen protection, cooled to room temperature, and washed with water to obtain the porous carbon-supported copper catalyst (NCP@NC-Cu). This catalyst retains a three-dimensional interconnected porous structure, with the active component (copper species) mainly distributed within the pores of the NCP support, and possesses a large specific surface area and abundant nitrogen. The catalyst was applied to the N-formylation reaction of amines with CO2 and H2 to prepare formamide compounds, exhibiting excellent catalytic activity, recyclability, and good substrate versatility, showing promising application prospects.

Description

Technical Field

[0001] This invention belongs to the field of catalyst preparation technology, and particularly relates to a porous carbon-supported copper catalyst, its preparation method and application. Background Technology

[0002] Formamides are an important class of organic intermediates, widely used in pharmaceutical synthesis, dye synthesis, leather processing, textiles, organic solvents, and many other fields, with huge market demand. Traditional methods for preparing formamides often use carbon monoxide, formic acid, acyl chlorides, acid anhydrides, etc., as acylation reagents to carry out acylation reactions with amine compounds. These methods have many drawbacks, such as high raw material costs and the generation of a large amount of waste during the reaction process.

[0003] Using abundant, non-toxic, and renewable CO2 as a carbon source, and combining it with H2 to construct a green acylation system for the N-formylation of amine compounds to prepare formamide, has become a current research hotspot in the field of catalysis. This route not only effectively utilizes CO2, a greenhouse gas, to alleviate environmental pressure, but also achieves an atom-economic reaction, demonstrating significant environmental and economic benefits. However, this reaction process suffers from challenges such as the difficulty of CO2 activation and slow reaction kinetics, necessitating the use of highly efficient catalysts to ensure efficient reaction execution.

[0004] Currently, catalysts used for the N-formylation reaction of amines with CO2 and H2 mainly include noble metal catalysts and non-noble metal catalysts. Noble metal catalysts (such as Pd, Pt, Rh, Ir, etc.), for example, the systems reported in patents CN119955072A and CN119869554A, while possessing high catalytic activity, suffer from resource scarcity and high cost, limiting their large-scale industrial application. Non-noble metal catalysts (such as Cu, Ni, Co, etc.) have become a research focus in this field due to their abundant resources, low cost, and environmental friendliness. Among them, copper-based catalysts have attracted widespread attention due to their excellent catalytic performance and good selectivity.

[0005] Catalyst supports have a significant impact on the dispersion, stability, and overall catalytic performance of active components. Three-dimensional interconnected porous carbon materials, due to their large-channel structure, excellent channel connectivity, high specific surface area, and good chemical stability, can effectively confine active components within the channels, which is beneficial for significantly improving the catalytic activity and cycle stability of catalysts.

[0006] In the prior art, porous carbon supports used to load copper active components generally suffer from problems such as unreasonable pore structure (e.g., small pore size, poor pore connectivity), lack of surface active coordination sites, and disordered doping of heteroatoms such as N. These problems lead to easy aggregation and poor dispersion of copper active components, and make it difficult to fully contact the reaction substrate. Consequently, the catalytic activity and recycling performance of the catalyst are significantly reduced, limiting its practical application.

[0007] Therefore, developing a porous carbon-supported copper catalyst with a simple preparation process, excellent carrier pore structure, abundant nitrogen element, uniform dispersion of active components, and high catalytic activity, high selectivity, and good recyclability for the N-formylation reaction of amines with CO2 and H2 to prepare formamide has important theoretical significance and industrial application value, and is also a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0008] To address the aforementioned technical problems, this invention proposes a porous carbon-supported copper catalyst, its preparation method, and its applications. This invention provides a porous carbon-supported copper catalyst with a simple preparation process, excellent pore structure, abundant nitrogen, uniform dispersion of active components, and high catalytic activity, high selectivity, and excellent recyclability. This catalyst can catalyze the N-formylation reaction of amines with CO2 and H2 to prepare formamide compounds, solving the technical problems of unreasonable pore structure, easy agglomeration of active components, low catalytic efficiency, and high cost of precious metal catalysts in existing catalysts. Simultaneously, it achieves the green and efficient utilization of CO2.

[0009] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a method for preparing a porous carbon-supported copper catalyst, comprising the following steps: Tetraphenylporphyrin copper(II) and tetraphenylporphyrin were mixed, chloroform was added, and the mixture was stirred until homogeneous to obtain a tetraphenylporphyrin copper(II)-tetraphenylporphyrin chloroform mixed solution; Three-dimensional interconnected ordered porous carbon (NCP) was added to the tetraphenylporphyrin copper(II)-tetraphenylporphyrin chloroform mixed solution, stirred for adsorption, rotary evaporated, and vacuum dried to obtain an NCP intermediate co-adsorbed with tetraphenylporphyrin copper(II) and tetraphenylporphyrin. The alkali was added to methanol and stirred until homogeneous to obtain an alkaline solution. The NCP intermediate was added to the alkaline solution, stirred, and then rotary evaporated and vacuum dried to obtain an NCP precursor adsorbed with tetraphenylporphyrin copper(II), tetraphenylporphyrin and alkali components. The NCP precursor was subjected to programmed temperature pyrolysis in a nitrogen atmosphere. The resulting product was washed with water and dried to obtain the porous carbon-supported copper catalyst (NCP@NC-Cu).

[0010] This invention leverages the structural advantages of three-dimensional interconnected porous carbon materials (three-dimensional interconnected ordered porous carbon), such as their large pore structure and excellent pore connectivity, to prepare a three-dimensional interconnected nitrogen-doped porous carbon supported copper catalyst. The catalyst is prepared by in-situ pyrolysis within the support, where tetraphenylporphyrin copper(II) and tetraphenylporphyrin (serving as nitrogen and copper sources) and a base (serving as an activator) are adsorbed. By selecting specific precursors and supports and combining them with a base activation process, this invention effectively overcomes the technical challenges of irregular pores, disordered nitrogen doping, and poor stability in traditional nitrogen-doped porous carbon materials, significantly improving the catalytic activity and stability of the catalyst. Specifically, this invention uses three-dimensional interconnected ordered porous carbon with uniform pore size (30 nm) as a support. The unique macroporous structure, excellent pore connectivity, and high specific surface area of ​​this support not only provide ample space for loading active components but also effectively reduce mass transfer resistance between substrate and product during the reaction. Simultaneously, it can form a good confinement effect on copper active species, inhibiting copper particle agglomeration during pyrolysis and catalytic reactions, thus laying a solid structural foundation for improved catalytic performance. This invention uses tetraphenylporphyrin copper(II) and tetraphenylporphyrin as the copper source and nitrogen source, respectively. When mixed in a certain molar ratio, they form a homogeneous and stable system in chloroform solvent, which is then uniformly loaded into the pores of the porous carbon support through adsorption. Among them, tetraphenylporphyrin copper(II) can directly provide copper active species, while tetraphenylporphyrin acts as an auxiliary nitrogen source, working synergistically with tetraphenylporphyrin copper(II) to ensure uniform nitrogen doping around the active sites during subsequent pyrolysis. This nitrogen doping method can significantly improve the adsorption stability of copper species on the support surface, preventing them from detaching during subsequent catalytic reactions. The alkaline component can play an activating role during pyrolysis, not only further regulating the pore structure of the porous carbon support and increasing its specific surface area, but also helping to remove impurities in the system, thereby further enhancing the catalytic activity of the catalyst.

[0011] Furthermore, the molar ratio of the tetraphenylporphyrin copper(II) to the tetraphenylporphyrin is 1:(0.5~10).

[0012] Furthermore, the total mass ratio of the alkali to tetraphenylporphyrin copper(II) and tetraphenylporphyrin is (0.5~2):1.

[0013] Furthermore, the alkali is selected from KOH or NaOH.

[0014] Furthermore, the total mass ratio of the NCP to tetraphenylporphyrin copper(II) and tetraphenylporphyrin is (1~5):1.

[0015] Furthermore, the temperature of the programmed pyrolysis treatment is 600~900℃, and the time is 2h.

[0016] This invention provides a porous carbon-supported copper catalyst prepared by the above method.

[0017] The present invention also provides an application of the above-mentioned porous carbon-supported copper catalyst in the N-formylation reaction of amines with CO2 and H2 to prepare formamide. The catalyst can effectively activate CO2 and accelerate the reaction kinetics.

[0018] Furthermore, the amine is selected from morpholine, p-toluidine, diethylamine, n-hexylamine, N-ethylpiperazine, benzylamine, or tetrahydroisoquinoline.

[0019] The present invention also provides a method for preparing formamide by catalytic N-formylation reaction of amine with CO2 and H2, comprising the following steps: adding 5 mL of methanol, 3 mmol of amine and the above-mentioned porous carbon-supported copper catalyst to a high-pressure reactor, then charging H2 at 3.0 MPa and CO2 at 2.0 MPa respectively, sealing the reactor, and reacting at 150 °C for 8 to 15 hours.

[0020] Furthermore, the amount of the porous carbon-supported copper catalyst is 1 mol% (relative to the substrate amine). Compared with existing catalysts for the N-formylation reaction of amines with CO2 and H2, the porous carbon-supported copper catalyst provided by this invention has the following advantages: (1) The present invention uses three-dimensional interconnected ordered porous carbon (NCP) as a support. Its pore size is uniform (30 nm), its pore connectivity is excellent and its specific surface area is high. It can effectively confine the copper active components inside the pores, effectively improve the dispersibility of copper species, avoid the aggregation of active components, optimize the mass transfer efficiency, and enable the reaction substrate to fully contact the active sites, thereby greatly improving the catalytic activity.

[0021] (2) In this invention, tetraphenylporphyrin copper(II) and tetraphenylporphyrin are used as nitrogen source and copper source, respectively. The two work together to form abundant nitrogen active coordination sites on the catalyst surface. There is a strong coordination effect between nitrogen and copper species, which can stabilize the copper active components and regulate the electronic structure of copper species, thereby improving the catalytic activity, selectivity and cycle stability of the catalyst.

[0022] (3) The present invention introduces KOH or NaOH as an activator, which can not only further regulate the pore structure of the porous carbon support, increase the specific surface area and optimize the pore size distribution, but also promote the carbonization process of the precursor and improve the catalytic performance.

[0023] (4) The present invention uses non-precious metal copper as the active component. Compared with precious metal catalysts such as Pd and Pt, copper is abundant, inexpensive, and environmentally friendly, effectively solving the problem of scarce resources and high prices of precious metal catalysts, and is more suitable for large-scale industrial application.

[0024] (5) When the catalyst of this invention is applied to the N-formylation reaction of amines with CO2 and H2, it exhibits excellent catalytic activity, high selectivity and good recycling performance. It can efficiently convert CO2 to formamide compounds under mild conditions, which not only realizes the green resource utilization of CO2 and alleviates environmental pressure, but also obtains high-value organic intermediates. It has good environmental and economic benefits and broad application prospects. Attached Figure Description

[0025] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 The nitrogen adsorption-desorption isotherm of NCP@NC-Cu-1 prepared in Example 1 is shown.

[0026] Figure 2 The image shows the pore size distribution of NCP@NC-Cu-1 prepared in Example 1.

[0027] Figure 3 This is a SEM image of NCP@NC-Cu-1 prepared in Example 1.

[0028] Figure 4 This is a TEM image of NCP@NC-Cu-1 prepared in Example 1.

[0029] Figure 5 The image shows an HRTEM image of NCP@NC-Cu-1 prepared in Example 1.

[0030] Figure 6 The target product N-formylmorpholine prepared for test example 1 1 H NMR spectrum. Detailed Implementation

[0031] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0032] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0033] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0034] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0035] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0036] An embodiment of the present invention provides a method for preparing a porous carbon-supported copper catalyst, comprising the following steps: (1) Preparation of metal complex solution: Mix tetraphenylporphyrin copper(II) with tetraphenylporphyrin, add chloroform, stir evenly to obtain a uniform and transparent tetraphenylporphyrin copper(II)-tetraphenylporphyrin chloroform mixed solution; (2) Adsorption on the support: Three-dimensional interconnected ordered porous carbon (NCP) was added to a tetraphenylporphyrin copper(II)-tetraphenylporphyrin chloroform mixed solution (NCP as support), and the mixture was stirred to allow tetraphenylporphyrin copper(II) and tetraphenylporphyrin to be fully adsorbed on the surface and in the pores of the NCP support; the chloroform solvent in the system was removed by rotary evaporation, and the mixture was dried under vacuum to obtain the NCP intermediate with tetraphenylporphyrin copper(II) and tetraphenylporphyrin co-adsorbed. (3) Preparation of alkaline solution and preparation of precursor: Add alkali to methanol and stir evenly to obtain an alkaline solution; add NCP intermediate to alkaline solution, stir and then remove solvent by rotary evaporation, and vacuum dry to obtain NCP precursor adsorbed with tetraphenylporphyrin copper(II), tetraphenylporphyrin and alkaline components; (4) Precursor pyrolysis: The NCP precursor was subjected to programmed temperature pyrolysis in a nitrogen atmosphere. The resulting product was washed with water until neutral and dried to obtain a porous carbon-supported copper catalyst, denoted as NCP@NC-Cu.

[0037] This invention utilizes three-dimensional interconnected ordered porous carbon (NCP) with a large-pore structure as a support, tetraphenylporphyrin copper(II) and tetraphenylporphyrin as nitrogen and copper sources, and KOH or NaOH as activators to prepare an NCP precursor adsorbed with tetraphenylporphyrin copper(II), tetraphenylporphyrin, and an alkaline component through a two-step adsorption process. The precursor is then pyrolyzed at 600–900 °C under nitrogen protection, cooled to room temperature, and washed with water to obtain a porous carbon-supported copper catalyst (NCP@NC-Cu). This catalyst retains its three-dimensional interconnected porous structure, with the active component (copper species) mainly distributed within the pores of the NCP support, and possesses a large specific surface area and abundant nitrogen. When applied to the N-formylation reaction of amines with CO2 and H2 to prepare formamide compounds, this catalyst exhibits excellent catalytic activity, recyclability, and good substrate versatility, demonstrating promising application prospects.

[0038] In a preferred embodiment of the present invention, the pore size of NCP is 30 nm.

[0039] In a preferred embodiment of the present invention, before NCP is added to the tetraphenylporphyrin copper(II)-tetraphenylporphyrin chloroform mixed solution, a drying pretreatment is performed. The specific process is as follows: NCP with a pore size of 30 nm is placed in a vacuum drying oven at 100 °C and dried for 10 h to remove residual moisture and organic impurities. After drying, it is taken out and placed in a desiccator to cool to room temperature for later use.

[0040] In a preferred embodiment of the present invention, the molar ratio of tetraphenylporphyrin copper(II) to tetraphenylporphyrin is 1:(0.5~10), preferably 1:(2~4), and more preferably 1:3. This ratio can ensure a reasonable ratio of nitrogen source to copper source, promote uniform dispersion of copper species and effective doping of nitrogen element, while avoiding copper component being buried and increasing the number of catalyst active sites.

[0041] In a preferred embodiment of the present invention, the total mass of tetraphenylporphyrin copper(II) and tetraphenylporphyrin is 0.5 g.

[0042] In a preferred embodiment of the present invention, the stirring adsorption is carried out at room temperature for 30 minutes.

[0043] In a preferred embodiment of the present invention, the amount of alkali used satisfies the following: the total mass ratio of alkali to tetraphenylporphyrin copper(II) and tetraphenylporphyrin is (0.5~2):1, preferably (1~2):1; an appropriate amount of alkali can avoid insufficient activation of the carrier due to insufficient amount, resulting in a low specific surface area; while excessive amount will lead to problems such as increased post-treatment (such as washing) costs.

[0044] In a preferred embodiment of the present invention, the alkali is selected from KOH or NaOH, preferably KOH; KOH, as an activator, can better improve the pore structure of the catalyst and increase the specific surface area.

[0045] In a preferred embodiment of the present invention, the amount of NCP carrier satisfies the following: the total mass ratio of NCP to tetraphenylporphyrin copper(II) and tetraphenylporphyrin is (1~5):1, preferably (2~4):1; this ratio can ensure the uniform dispersion of active components (copper species, nitrogen element) in the pores, while making full use of the pore structure advantages of the carrier to improve mass transfer efficiency.

[0046] In a preferred embodiment of the present invention, after the NCP intermediate is added to the alkaline solution, the stirring time is 30 minutes.

[0047] In a preferred embodiment of the present invention, the temperature of the programmed temperature pyrolysis treatment is 600~900℃, preferably 800℃; pyrolysis at 800℃ can fully carbonize the precursor to form a stable nitrogen-doped porous carbon structure, while realizing the monodispersity or small particle dispersion of copper species, avoiding insufficient carbonization and insufficient active sites due to excessively low temperature, or agglomeration of copper species and destruction of pore structure due to excessively high temperature; the time of the programmed temperature pyrolysis treatment is 2h.

[0048] In a preferred embodiment of the present invention, the heating rate of the programmed temperature pyrolysis treatment is 5 K·min. -1 .

[0049] An embodiment of the present invention provides a porous carbon-supported copper catalyst prepared by the above method.

[0050] The embodiments of the present invention also provide an application of the above-mentioned porous carbon-supported copper catalyst in the N-formylation reaction of amines with CO2 and H2 to prepare formamide. The catalyst can effectively activate CO2 and accelerate the reaction kinetics.

[0051] In a preferred embodiment of the present invention, the amine is selected from morpholine, p-toluidine ( ), diethylamine ( ), n-hexylamine ( ), N-ethylpiperazine ( ), benzylamine ( ) or tetrahydroisoquinoline ( ).

[0052] This invention also provides a method for preparing formamide by catalytic N-formylation reaction of amine with CO2 and H2, comprising the following steps: adding 5 mL of methanol, 3 mmol of amine, and the above-mentioned porous carbon-supported copper catalyst to a high-pressure reactor, then charging with 3.0 MPa of H2 and 2.0 MPa of CO2 to ensure the reaction system reaches the required pressure, sealing the reactor, and reacting at 150 °C for 8-15 hours. After the reaction is completed, the reaction solution is quantitatively analyzed by gas chromatography.

[0053] In a preferred embodiment of the invention, the amount of porous carbon-supported copper catalyst is 1 mol% (relative to the substrate amine).

[0054] Unless otherwise specified, the room temperature in this invention is 25±2℃.

[0055] All raw materials used in the embodiments of this invention were purchased commercially. The three-dimensional interconnected ordered porous carbon (NCP, pore size 30 nm) used in the following embodiments was purchased from Jiangsu Xianfeng Nanomaterials Technology Co., Ltd.; tetraphenylporphyrin and tetraphenylporphyrin copper(II) were purchased from Anhui Zesheng Technology Co., Ltd. Before use, the NCP was dried in a vacuum drying oven at 100 ℃ for 10 h to remove residual moisture and organic impurities from the carrier. After drying, it was removed and cooled to room temperature in a desiccator for later use.

[0056] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.

[0057] The technical solution of the present invention will be further illustrated by the following embodiments.

[0058] Example 1 Porous carbon-supported copper catalyst (NCP@NC-Cu-1) Tetraphenylporphyrin copper(II) and tetraphenylporphyrin were added to 20 mL of chloroform solvent at a molar ratio of 1:3 (0.1340 g of tetraphenylporphyrin and 0.3660 g of tetraphenylporphyrin, respectively). The mixture was stirred at room temperature for 2 h to obtain a tetraphenylporphyrin copper(II)-tetraphenylporphyrin chloroform mixed solution. 1.0 g of dried three-dimensional interconnected ordered porous carbon (NCP, pore size 30 nm) was added to 20 mL of the prepared tetraphenylporphyrin copper(II)-tetraphenylporphyrin chloroform mixed solution and stirred at room temperature for 30 min for adsorption. Subsequently, the chloroform solvent in the system was removed by rotary evaporation, and then the system was vacuum dried to obtain the NCP intermediate co-adsorbed by tetraphenylporphyrin copper(II) and tetraphenylporphyrin. 0.5 g of KOH was added to 5 mL of methanol solvent, and the mixture was stirred continuously until the solid was completely dissolved to prepare an alkaline solution. The co-adsorbed NCP intermediate was added to the 5 mL alkaline solution prepared above, and the mixture was stirred at a constant temperature for 30 min. Subsequently, the solvent was removed by rotary evaporation, and the solution was dried in a vacuum drying oven at 80 ℃ for 12 h to obtain an NCP precursor adsorbed with tetraphenylporphyrin copper(II), tetraphenylporphyrin, and the alkaline component. The obtained NCP precursor was placed in a tube furnace and subjected to programmed temperature pyrolysis under a nitrogen atmosphere at a heating rate of 5 K·min. -1 The temperature was raised to 800 °C and held constant for 2 h. After pyrolysis, the product was taken out and washed repeatedly with deionized water until the pH of the washing solution was neutral. Finally, the washed solid was placed in a vacuum drying oven at 50 °C and dried for 24 h to obtain the target porous carbon-supported copper catalyst, denoted as NCP@NC-Cu-1.

[0059] Elemental analysis showed that NCP@NC-Cu-1 contained 0.94 wt% nitrogen and 0.82 wt% copper. Figure 1 and Figure 2 The images show the nitrogen adsorption-desorption isotherms and pore size distribution of NCP@NC-Cu-1, indicating that the specific surface area of ​​NCP@NC-Cu-1 is 602 m². 2 ·g -1 The average pore size is 12.1 nm. Figure 3 The image shows a SEM image of NCP@NC-Cu-1, which reveals that the prepared NCP@NC-Cu-1 exhibits a loose and porous structure. Figure 4 The TEM image of NCP@NC-Cu-1 shows that NCP@NC-Cu-1 retains a good three-dimensional interconnected porous structure, indicating that the pyrolysis reactions of porphyrin and other substances mainly occur in the pores and the pores are not blocked. Figure 5The HRTEM image of NCP@NC-Cu-1 shows no obvious copper particle formation, indicating that copper is highly dispersed in the support. XPS results indicate that Cu is mainly in the 0 valence state, with a small amount of Cu. + Furthermore, there is a strong interaction between Cu and nitrogen.

[0060] Example 2 Porous carbon-supported copper catalyst (NCP@NC-Cu-2) A total of 0.5 g of tetraphenylporphyrin copper(II) and tetraphenylporphyrin was added to 20 mL of chloroform solvent at a molar ratio of 1:0.5 (0.3437 g of tetraphenylporphyrin and 0.1563 g of tetraphenylporphyrin, respectively). The mixture was stirred continuously at room temperature for 2 h to obtain a tetraphenylporphyrin copper(II)-tetraphenylporphyrin chloroform mixed solution. 1.0 g of dried NCP was added to 20 mL of the prepared tetraphenylporphyrin copper(II)-tetraphenylporphyrin chloroform mixed solution and stirred at room temperature for 30 min for adsorption. The chloroform solvent was then removed from the system by rotary evaporation, followed by vacuum drying to obtain an NCP intermediate co-adsorbed with tetraphenylporphyrin copper(II) and tetraphenylporphyrin. 0.5 g of KOH was added to 5 mL of methanol solvent and stirred continuously until the solid was completely dissolved to prepare an alkaline solution. The co-adsorbed NCP intermediate was added to 5 mL of a prepared alkaline solution and stirred at a constant temperature for 30 min. The solvent was then removed by rotary evaporation, followed by drying in a vacuum drying oven at 80 °C for 12 h to obtain an NCP precursor adsorbed with tetraphenylporphyrin copper(II), tetraphenylporphyrin, and the alkaline component. The obtained NCP precursor was placed in a tube furnace and subjected to programmed temperature pyrolysis under a nitrogen atmosphere at a heating rate of 5 K·min. -1 The temperature was raised to 800 °C and held constant for 2 h. After pyrolysis, the product was taken out and washed repeatedly with deionized water until the pH of the washing solution was neutral. Finally, the washed solid was placed in a vacuum drying oven at 50 °C and dried for 24 h to obtain the target porous carbon-supported copper catalyst, denoted as NCP@NC-Cu-2.

[0061] Elemental analysis showed that NCP@NC-Cu-2 contained 0.87 wt% nitrogen and 1.92 wt% copper. Nitrogen adsorption-desorption analysis showed that NCP@NC-Cu-2 had a specific surface area of ​​573 m². 2 ·g -1The average pore size is 11.5 nm. SEM analysis shows that NCP@NC-Cu-2 exhibits a loose porous structure. TEM analysis shows that NCP@NC-Cu-2 retains a well-preserved three-dimensional interconnected porous structure, indicating that the pyrolysis reactions of porphyrins mainly occur within the pores, and the pores are not blocked. HRTEM analysis shows that copper in NCP@NC-Cu-2 is well dispersed within the support, but exhibits some aggregation to form Cu nanoparticles, with Cu particle sizes ranging from approximately 0.9 to 2.2 nm. XPS results indicate that Cu is mainly in the 0 valence state, containing a small amount of Cu. + Furthermore, there is a strong interaction between Cu and nitrogen.

[0062] Example 3 Porous carbon-supported copper catalyst (NCP@NC-Cu-3) A total of 0.5 g of tetraphenylporphyrin copper(II) and tetraphenylporphyrin was added to 20 mL of chloroform solvent at a molar ratio of 1:10 (0.0500 g of tetraphenylporphyrin copper(II) and 0.4500 g of tetraphenylporphyrin, respectively). The mixture was stirred continuously at room temperature for 2 h to obtain a tetraphenylporphyrin copper(II)-tetraphenylporphyrin chloroform mixed solution. 1.0 g of dried NCP was added to 20 mL of the prepared tetraphenylporphyrin copper(II)-tetraphenylporphyrin chloroform mixed solution and stirred at room temperature for 30 min for adsorption. The chloroform solvent was then removed from the system by rotary evaporation, followed by vacuum drying to obtain an NCP intermediate co-adsorbed with tetraphenylporphyrin copper(II) and tetraphenylporphyrin. 0.5 g of KOH was added to 5 mL of methanol solvent and stirred continuously until the solid was completely dissolved to prepare an alkaline solution. The co-adsorbed NCP intermediate was added to 5 mL of a prepared alkaline solution and stirred at a constant temperature for 30 min. The solvent was then removed by rotary evaporation, followed by drying in a vacuum drying oven at 80 °C for 12 h to obtain an NCP precursor adsorbed with tetraphenylporphyrin copper(II), tetraphenylporphyrin, and the alkaline component. The obtained NCP precursor was placed in a tube furnace and subjected to programmed temperature pyrolysis under a nitrogen atmosphere at a heating rate of 5 K·min. -1 The temperature was raised to 800 °C and held constant for 2 h. After pyrolysis, the product was taken out and washed repeatedly with deionized water until the pH of the washing solution was neutral. Finally, the washed solid was placed in a vacuum drying oven at 50 °C and dried for 24 h to obtain the target porous carbon-supported copper catalyst, denoted as NCP@NC-Cu-3.

[0063] Elemental analysis showed that NCP@NC-Cu-3 contained 1.02 wt% nitrogen and 0.30 wt% copper. Nitrogen adsorption-desorption analysis showed that NCP@NC-Cu-3 had a specific surface area of ​​627 m². 2 ·g -1The average pore size is 12.8 nm. SEM analysis shows that NCP@NC-Cu-3 exhibits a loose porous structure. TEM analysis shows that NCP@NC-Cu-3 retains a well-preserved three-dimensional interconnected porous structure, indicating that pyrolysis reactions such as porphyrin mainly occur within the pores, and the pores are not blocked. HRTEM analysis shows that copper in NCP@NC-Cu-3 is highly dispersed in the support, and no Cu particles were found. XPS results indicate that Cu is mainly in the 0 valence state, containing a small amount of Cu. + Furthermore, there is a strong interaction between Cu and nitrogen.

[0064] Example 4 Porous carbon-supported copper catalyst (NCP@NC-Cu-4) Tetraphenylporphyrin copper(II) and tetraphenylporphyrin were added to 20 mL of chloroform solvent at a molar ratio of 1:3 (0.1340 g of tetraphenylporphyrin and 0.3660 g of tetraphenylporphyrin, respectively). The mixture was stirred continuously at room temperature for 2 h to obtain a tetraphenylporphyrin copper(II)-tetraphenylporphyrin chloroform mixed solution. 2.5 g of dried NCP was added to 20 mL of the prepared tetraphenylporphyrin copper(II)-tetraphenylporphyrin chloroform mixed solution and stirred at room temperature for 30 min for adsorption. The chloroform solvent was then removed from the system by rotary evaporation, followed by vacuum drying to obtain an NCP intermediate co-adsorbed with tetraphenylporphyrin copper(II) and tetraphenylporphyrin. 0.5 g of KOH was added to 5 mL of methanol solvent and stirred continuously until the solid was completely dissolved to prepare an alkaline solution. The co-adsorbed NCP intermediate was added to 5 mL of a prepared alkaline solution and stirred at a constant temperature for 30 min. The solvent was then removed by rotary evaporation, followed by drying in a vacuum drying oven at 80 °C for 12 h to obtain an NCP precursor adsorbed with tetraphenylporphyrin copper(II), tetraphenylporphyrin, and the alkaline component. The obtained NCP precursor was placed in a tube furnace and subjected to programmed temperature pyrolysis under a nitrogen atmosphere at a heating rate of 5 K·min. -1 The temperature was raised to 800 °C and held constant for 2 h. After pyrolysis, the product was taken out and washed repeatedly with deionized water until the pH of the washing solution was neutral. Finally, the washed solid was placed in a vacuum drying oven at 50 °C and dried for 24 h to obtain the target porous carbon-supported copper catalyst, denoted as NCP@NC-Cu-4.

[0065] Elemental analysis showed that NCP@NC-Cu-4 contained 0.46 wt% nitrogen and 0.41 wt% copper. Nitrogen adsorption-desorption analysis showed that NCP@NC-Cu-4 had a specific surface area of ​​417 m². 2 ·g -1The average pore size is 17.2 nm. SEM analysis shows that NCP@NC-Cu-4 exhibits a loose porous structure. TEM analysis shows that NCP@NC-Cu-4 retains a well-preserved three-dimensional interconnected porous structure, indicating that the pyrolysis reactions of porphyrins mainly occur within the pores, and the pores are not blocked. HRTEM analysis shows that copper in NCP@NC-Cu-4 is highly dispersed in the support, and no Cu particles were found. XPS results indicate that Cu is mainly in the 0 valence state, containing a small amount of Cu. + Furthermore, there is a strong interaction between Cu and nitrogen.

[0066] Example 5 Porous carbon-supported copper catalyst (NCP@NC-Cu-5) Tetraphenylporphyrin copper(II) and tetraphenylporphyrin were added to 20 mL of chloroform solvent at a molar ratio of 1:3 (0.1340 g of tetraphenylporphyrin and 0.3660 g of tetraphenylporphyrin, respectively). The mixture was stirred continuously at room temperature for 2 h to obtain a tetraphenylporphyrin copper(II)-tetraphenylporphyrin chloroform mixed solution. 0.5 g of dried NCP was added to 20 mL of the prepared tetraphenylporphyrin copper(II)-tetraphenylporphyrin chloroform mixed solution and stirred at room temperature for 30 min for adsorption. The chloroform solvent was then removed from the system by rotary evaporation, followed by vacuum drying to obtain an NCP intermediate co-adsorbed with tetraphenylporphyrin copper(II) and tetraphenylporphyrin. 0.5 g of KOH was added to 5 mL of methanol solvent and stirred continuously until the solid was completely dissolved to prepare an alkaline solution. The co-adsorbed NCP intermediate was added to 5 mL of a prepared alkaline solution and stirred at a constant temperature for 30 min. The solvent was then removed by rotary evaporation, followed by drying in a vacuum drying oven at 80 °C for 12 h to obtain an NCP precursor adsorbed with tetraphenylporphyrin copper(II), tetraphenylporphyrin, and the alkaline component. The obtained NCP precursor was placed in a tube furnace and subjected to programmed temperature pyrolysis under a nitrogen atmosphere at a heating rate of 5 K·min. -1 The temperature was raised to 800 °C and held constant for 2 h. After pyrolysis, the product was taken out and washed repeatedly with deionized water until the pH of the washing solution was neutral. Finally, the washed solid was placed in a vacuum drying oven at 50 °C and dried for 24 h to obtain the target porous carbon-supported copper catalyst (denoted as NCP@NC-Cu-5).

[0067] Elemental analysis showed that NCP@NC-Cu-5 contained 1.73 wt% nitrogen and 1.21 wt% copper. Nitrogen adsorption-desorption analysis showed that NCP@NC-Cu-5 had a specific surface area of ​​411 m². 2 ·g -1The average pore size is 7.9 nm. SEM analysis shows that NCP@NC-Cu-5 exhibits a loose porous structure. TEM analysis shows that NCP@NC-Cu-5 possesses a certain degree of three-dimensional interconnected porous structure, indicating that pyrolysis reactions such as porphyrin mainly occur within the pores, but some channels are blocked. HRTEM analysis shows that copper in NCP@NC-Cu-5 is well dispersed within the support, but exhibits a small number of aggregated particles, with Cu particle sizes all less than 1.5 nm. XPS results indicate that Cu is mainly in the 0 valence state, containing a small amount of Cu. + Furthermore, there is a strong interaction between Cu and nitrogen.

[0068] Example 6 Porous carbon-supported copper catalyst (NCP@NC-Cu-6) Tetraphenylporphyrin copper(II) and tetraphenylporphyrin were added to 20 mL of chloroform solvent at a molar ratio of 1:3 (0.1340 g of tetraphenylporphyrin and 0.3660 g of tetraphenylporphyrin, respectively). The mixture was stirred continuously at room temperature for 2 h to obtain a tetraphenylporphyrin copper(II)-tetraphenylporphyrin chloroform mixed solution. 1.0 g of dried NCP was added to 20 mL of the prepared tetraphenylporphyrin copper(II)-tetraphenylporphyrin chloroform mixed solution and stirred at room temperature for 30 min for adsorption. Subsequently, the chloroform solvent in the system was removed by rotary evaporation, followed by vacuum drying to obtain the NCP intermediate co-adsorbed by tetraphenylporphyrin copper(II) and tetraphenylporphyrin. 0.25 g of KOH was added to 5 mL of methanol solvent and stirred continuously until the solid was completely dissolved to prepare an alkaline solution. The co-adsorbed NCP intermediate was added to 5 mL of a prepared alkaline solution and stirred at a constant temperature for 30 min. The solvent was then removed by rotary evaporation, followed by drying in a vacuum drying oven at 80 °C for 12 h to obtain an NCP precursor adsorbed with tetraphenylporphyrin copper(II), tetraphenylporphyrin, and the alkaline component. The obtained NCP precursor was placed in a tube furnace and subjected to programmed temperature pyrolysis under a nitrogen atmosphere at a heating rate of 5 K·min. -1 The temperature was raised to 800 °C and held constant for 2 h. After pyrolysis, the product was taken out and washed repeatedly with deionized water until the pH of the washing solution was neutral. Finally, the washed solid was placed in a vacuum drying oven at 50 °C and dried for 24 h to obtain the target porous carbon-supported copper catalyst, denoted as NCP@NC-Cu-6.

[0069] Elemental analysis showed that NCP@NC-Cu-6 contained 0.90 wt% nitrogen and 0.83 wt% copper. Nitrogen adsorption-desorption analysis showed that NCP@NC-Cu-6 had a specific surface area of ​​348 m². 2 ·g -1The average pore size is 10.3 nm. SEM analysis shows that NCP@NC-Cu-6 exhibits a loose porous structure. TEM analysis shows that NCP@NC-Cu-6 retains a well-preserved three-dimensional interconnected porous structure, indicating that pyrolysis reactions such as porphyrin mainly occur within the pores, and that the pores are not significantly blocked. HRTEM analysis shows that copper in NCP@NC-Cu-6 is highly dispersed in the support, and no Cu particles were found. XPS results indicate that Cu is mainly in the 0 valence state, containing a small amount of Cu. + Furthermore, there is a strong interaction between Cu and nitrogen.

[0070] Example 7 Porous carbon-supported copper catalyst (NCP@NC-Cu-7) A total of 0.5 g of tetraphenylporphyrin copper(II) and tetraphenylporphyrin were added to 20 mL of chloroform solvent at a molar ratio of 1:3 (0.1340 g of tetraphenylporphyrin and 0.3660 g of tetraphenylporphyrin, respectively). The mixture was stirred continuously at room temperature for 2 h to obtain a tetraphenylporphyrin copper(II)-tetraphenylporphyrin chloroform mixed solution. 1.0 g of dried NCP was added to 20 mL of the prepared tetraphenylporphyrin copper(II)-tetraphenylporphyrin chloroform mixed solution and stirred at room temperature for 30 min for adsorption. The chloroform solvent was then removed from the system by rotary evaporation, followed by vacuum drying to obtain an NCP intermediate co-adsorbed with tetraphenylporphyrin copper(II) and tetraphenylporphyrin. 1.0 g of KOH was added to 5 mL of methanol solvent and stirred continuously until the solid was completely dissolved to prepare an alkaline solution. The co-adsorbed NCP intermediate was added to 5 mL of a prepared alkaline solution and stirred at a constant temperature for 30 min. The solvent was then removed by rotary evaporation, followed by drying in a vacuum drying oven at 80 °C for 12 h to obtain an NCP precursor adsorbed with tetraphenylporphyrin copper(II), tetraphenylporphyrin, and the alkaline component. The obtained NCP precursor was placed in a tube furnace and subjected to programmed temperature pyrolysis under a nitrogen atmosphere at a heating rate of 5 K·min. -1 The temperature was raised to 800 °C and held constant for 2 h. After pyrolysis, the product was taken out and washed repeatedly with deionized water until the pH of the washing solution was neutral. Finally, the washed solid was placed in a vacuum drying oven at 50 °C and dried for 24 h to obtain the target porous carbon-supported copper catalyst, denoted as NCP@NC-Cu-7.

[0071] Elemental analysis showed that NCP@NC-Cu-7 contained 1.03 wt% nitrogen and 0.69 wt% copper. Nitrogen adsorption-desorption analysis showed that NCP@NC-Cu-7 had a specific surface area of ​​621 m². 2 ·g -1The average pore size is 12.7 nm. SEM analysis shows that NCP@NC-Cu-7 exhibits a loose porous structure. TEM analysis shows that NCP@NC-Cu-7 retains a well-preserved three-dimensional interconnected porous structure, indicating that the pyrolysis reactions of porphyrins mainly occur within the pores, and the pores are not blocked. HRTEM analysis shows that copper in NCP@NC-Cu-7 is highly dispersed in the support, and no Cu particles were found. XPS results indicate that Cu is mainly in the 0 valence state, containing a small amount of Cu. + Furthermore, there is a strong interaction between Cu and nitrogen.

[0072] Example 8 Porous carbon-supported copper catalyst (NCP@NC-Cu-8) Tetraphenylporphyrin copper(II) and tetraphenylporphyrin were added to 20 mL of chloroform solvent at a molar ratio of 1:3 (0.1340 g of tetraphenylporphyrin and 0.3660 g of tetraphenylporphyrin, respectively). The mixture was stirred continuously at room temperature for 2 h to obtain a tetraphenylporphyrin copper(II)-tetraphenylporphyrin chloroform mixed solution. 1.0 g of dried NCP was added to 20 mL of the prepared tetraphenylporphyrin copper(II)-tetraphenylporphyrin chloroform mixed solution and stirred at room temperature for 30 min for adsorption. Subsequently, the chloroform solvent in the system was removed by rotary evaporation, followed by vacuum drying to obtain the NCP intermediate co-adsorbed by tetraphenylporphyrin copper(II) and tetraphenylporphyrin. 0.5 g of NaOH was added to 5 mL of methanol solvent and stirred continuously until the solid was completely dissolved to prepare an alkaline solution. The co-adsorbed NCP intermediate was added to 5 mL of a prepared alkaline solution and stirred at a constant temperature for 30 min. The solvent was then removed by rotary evaporation, followed by drying in a vacuum drying oven at 80 °C for 12 h to obtain an NCP precursor adsorbed with tetraphenylporphyrin copper(II), tetraphenylporphyrin, and the alkaline component. The obtained NCP precursor was placed in a tube furnace and subjected to programmed temperature pyrolysis under a nitrogen atmosphere at a heating rate of 5 K·min. -1 The temperature was raised to 800 °C and held constant for 2 h. After pyrolysis, the product was taken out and washed repeatedly with deionized water until the pH of the washing solution was neutral. Finally, the washed solid was placed in a vacuum drying oven at 50 °C and dried for 24 h to obtain the target porous carbon-supported copper catalyst, denoted as NCP@NC-Cu-8.

[0073] Elemental analysis showed that NCP@NC-Cu-8 contained 0.92 wt% nitrogen and 0.83 wt% copper. Nitrogen adsorption-desorption analysis showed that NCP@NC-Cu-8 had a specific surface area of ​​519 m². 2 ·g -1The average pore size is 9.5 nm. SEM analysis shows that NCP@NC-Cu-8 exhibits a loose porous structure. TEM analysis shows that NCP@NC-Cu-8 retains a well-preserved three-dimensional interconnected porous structure, indicating that pyrolysis reactions such as porphyrin mainly occur within the pores, and that the pores are not significantly blocked. HRTEM analysis shows that copper in NCP@NC-Cu-8 is highly dispersed in the support, and no Cu particles were found. XPS results indicate that Cu is mainly in the 0 valence state, containing a small amount of Cu. + Furthermore, there is a strong interaction between Cu and nitrogen.

[0074] Comparative Example 1: Porous carbon-supported copper catalyst (NCP@NC-Cu-9) A total of 0.5 g of tetraphenylporphyrin copper(II) and tetraphenylporphyrin was added to 20 mL of chloroform solvent at a molar ratio of 1:3 (0.1340 g of tetraphenylporphyrin and 0.3660 g of tetraphenylporphyrin, respectively). The mixture was stirred continuously at room temperature for 2 h to obtain a tetraphenylporphyrin copper(II)-tetraphenylporphyrin chloroform mixed solution. 1.0 g of dried NCP was added to 20 mL of the prepared tetraphenylporphyrin copper(II)-tetraphenylporphyrin chloroform mixed solution and stirred at room temperature for 30 min for adsorption. The chloroform solvent was then removed from the system by rotary evaporation, followed by vacuum drying to obtain an NCP intermediate co-adsorbed with tetraphenylporphyrin copper(II) and tetraphenylporphyrin. The co-adsorbed NCP intermediate was placed directly in a tube furnace and subjected to programmed temperature pyrolysis under a nitrogen atmosphere at a heating rate of 5 K·min. -1 The temperature was raised to 800 °C and held constant for 2 h. After pyrolysis, the product was taken out and washed three times with deionized water. Finally, the washed solid was placed in a vacuum drying oven at 50 °C and dried for 24 h to obtain the target porous carbon-supported copper catalyst, denoted as NCP@NC-Cu-9.

[0075] Elemental analysis showed that NCP@NC-Cu-9 contained 0.88 wt% nitrogen and 0.84 wt% copper. Nitrogen adsorption-desorption analysis showed that NCP@NC-Cu-9 had a specific surface area of ​​178 m². 2 ·g -1 The average pore size is 6.9 nm. SEM analysis shows that NCP@NC-Cu-9 exhibits a loose porous structure. TEM analysis shows that NCP@NC-Cu-9 retains a relatively good three-dimensional interconnected porous structure, indicating that pyrolysis reactions such as porphyrin mainly occur within the pores, but some pore blockage exists. HRTEM analysis shows that copper in NCP@NC-Cu-9 is highly dispersed in the support, and no Cu particles were found. XPS results indicate that Cu is mainly in the 0 valence state, containing a small amount of Cu. + Furthermore, there is a strong interaction between Cu and nitrogen.

[0076] Example 9 Porous carbon-supported copper catalyst (NCP@NC-Cu-10) Tetraphenylporphyrin copper(II) and tetraphenylporphyrin were added to 20 mL of chloroform solvent at a molar ratio of 1:3 (0.1340 g of tetraphenylporphyrin and 0.3660 g of tetraphenylporphyrin, respectively). The mixture was stirred at room temperature for 2 h to obtain a tetraphenylporphyrin copper(II)-tetraphenylporphyrin chloroform mixed solution. 1.0 g of dried NCP was added to 20 mL of the prepared tetraphenylporphyrin copper(II)-tetraphenylporphyrin chloroform mixed solution and stirred at room temperature for 30 min for adsorption. The chloroform solvent was then removed from the system by rotary evaporation, followed by vacuum drying to obtain an NCP intermediate co-adsorbed with tetraphenylporphyrin copper(II) and tetraphenylporphyrin. 0.5 g of KOH was added to 5 mL of methanol solvent and stirred continuously until the solid was completely dissolved to prepare an alkaline solution. The co-adsorbed NCP intermediate was added to 5 mL of a prepared alkaline solution and stirred at a constant temperature for 30 min. The solvent was then removed by rotary evaporation, followed by drying in a vacuum drying oven at 80 °C for 12 h to obtain an NCP precursor adsorbed with tetraphenylporphyrin copper(II), tetraphenylporphyrin, and the alkaline component. The obtained NCP precursor was placed in a tube furnace and subjected to programmed temperature pyrolysis under a nitrogen atmosphere at a heating rate of 5 K·min. -1 The temperature was raised to 600 °C and held constant for 2 h. After pyrolysis, the product was taken out and washed repeatedly with deionized water until the pH of the washing solution was neutral. Finally, the washed solid was placed in a vacuum drying oven at 50 °C and dried for 24 h to obtain the target porous carbon-supported copper catalyst, denoted as NCP@NC-Cu-10.

[0077] Elemental analysis showed that NCP@NC-Cu-10 contained 1.05 wt% nitrogen and 0.77 wt% copper. Nitrogen adsorption-desorption analysis showed that NCP@NC-Cu-10 had a specific surface area of ​​437 m². 2 ·g -1 The average pore size is 9.4 nm. SEM analysis shows that NCP@NC-Cu-10 exhibits a loose porous structure. TEM analysis shows that NCP@NC-Cu-10 retains a well-preserved three-dimensional interconnected porous structure, indicating that pyrolysis reactions such as porphyrin mainly occur within the pores, and that the pores are not significantly blocked. HRTEM analysis shows that copper in NCP@NC-Cu-10 is highly dispersed in the support, and no Cu particles were found. XPS results indicate that Cu is mainly in the 0 valence state, containing a small amount of Cu. + Furthermore, there is a strong interaction between Cu and nitrogen.

[0078] Example 10 Porous carbon-supported copper catalyst (NCP@NC-Cu-11) Tetraphenylporphyrin copper(II) and tetraphenylporphyrin were added to 20 mL of chloroform solvent at a molar ratio of 1:3 (0.1340 g of tetraphenylporphyrin and 0.3660 g of tetraphenylporphyrin, respectively). The mixture was stirred at room temperature for 2 h to obtain a tetraphenylporphyrin copper(II)-tetraphenylporphyrin chloroform mixed solution. 1.0 g of dried NCP was added to 20 mL of the prepared tetraphenylporphyrin copper(II)-tetraphenylporphyrin chloroform mixed solution and stirred at room temperature for 30 min for adsorption. The chloroform solvent was then removed from the system by rotary evaporation, followed by vacuum drying to obtain an NCP intermediate co-adsorbed with tetraphenylporphyrin copper(II) and tetraphenylporphyrin. 0.5 g of KOH was added to 5 mL of methanol solvent and stirred continuously until the solid was completely dissolved to prepare an alkaline solution. The co-adsorbed NCP intermediate was added to 5 mL of a prepared alkaline solution and stirred at a constant temperature for 30 min. The solvent was then removed by rotary evaporation, followed by drying in a vacuum drying oven at 80 °C for 12 h to obtain an NCP precursor adsorbed with tetraphenylporphyrin copper(II), tetraphenylporphyrin, and the alkaline component. The obtained NCP precursor was placed in a tube furnace and subjected to programmed temperature pyrolysis under a nitrogen atmosphere at a heating rate of 5 K·min. -1 The temperature was raised to 900 °C and held constant for 2 h. After pyrolysis, the product was taken out and washed repeatedly with deionized water until the pH of the washing solution was neutral. Finally, the washed solid was placed in a vacuum drying oven at 50 °C and dried for 24 h to obtain the target porous carbon-supported copper catalyst, denoted as NCP@NC-Cu-11.

[0079] Elemental analysis showed that NCP@NC-Cu-11 contained 0.84 wt% nitrogen and 0.85 wt% copper. Nitrogen adsorption-desorption analysis showed that NCP@NC-Cu-11 had a specific surface area of ​​556 m². 2 ·g -1 The average pore size is 10.9 nm. SEM analysis shows that NCP@NC-Cu-11 exhibits a loose porous structure. TEM analysis shows that NCP@NC-Cu-11 retains a well-preserved three-dimensional interconnected porous structure, indicating that pyrolysis reactions such as porphyrin mainly occur within the pores, and that the pores are not significantly blocked. HRTEM analysis shows that copper in NCP@NC-Cu-11 is well dispersed in the support, but a small amount of Cu particles are present, with a particle size of approximately 1.6–2.2 nm. XPS results indicate that Cu is mainly in the 0 valence state, containing a small amount of Cu. + Furthermore, there is a certain interaction between Cu and nitrogen.

[0080] Comparative Example 2: Porous carbon-supported copper catalyst without NCP support (NC-Cu-1) 0.1340 g of tetraphenylporphyrin copper(II), 0.3660 g of tetraphenylporphyrin, and 0.5 g of KOH were added to 20 mL of methanol solvent, and the mixture was stirred and adsorbed at room temperature for 30 min. Subsequently, the methanol solvent was removed from the system by rotary evaporation to obtain a homogeneous precursor. The obtained precursor was placed in a tube furnace and subjected to programmed temperature pyrolysis under a nitrogen atmosphere at a heating rate of 5 K·min. -1 The temperature was raised to 800 °C and held constant for 2 h. After pyrolysis, the product was taken out and washed repeatedly with deionized water until the pH of the washing solution was neutral. Finally, the washed solid was placed in a vacuum drying oven at 50 °C and dried for 24 h to obtain a porous carbon-supported copper catalyst without NCP support, denoted as NC-Cu-1.

[0081] Elemental analysis showed that NC-Cu-1 contained 5.97 wt% nitrogen and 2.38 wt% copper. Nitrogen adsorption-desorption analysis showed that NC-Cu-1 had a specific surface area of ​​892 m². 2 ·g -1 The average pore size is 1.1 nm. SEM and TEM analyses showed that NC-Cu-1 had no obvious porous structure. HRTEM analysis showed that copper in NC-Cu-1 mainly exists in particle form, with particle sizes ranging from 2.4 to 6.7 nm. XPS results indicated that Cu is mainly in the 0 valence state, containing a small amount of Cu. + Furthermore, there is a certain interaction between Cu and nitrogen.

[0082] Comparative Example 3: Porous carbon-supported copper catalyst without NCP support (NC-Cu-2) 0.5 g chitosan, 0.036 g anhydrous copper acetate, and 0.5 g KOH were added to 20 mL of methanol solvent, and the mixture was stirred and adsorbed at room temperature for 30 min. Subsequently, the methanol solvent was removed from the system by rotary evaporation to obtain a homogeneous precursor. The obtained precursor was placed in a tube furnace and subjected to programmed temperature pyrolysis under a nitrogen atmosphere at a heating rate of 5 K·min. -1 The temperature was raised to 800 °C and held constant for 2 h. After pyrolysis, the product was taken out and washed repeatedly with deionized water until the pH of the washing solution was neutral. Finally, the washed solid was placed in a vacuum drying oven at 50 °C and dried for 24 h to obtain a porous carbon-supported copper catalyst without NCP support, denoted as NC-Cu-2.

[0083] Elemental analysis showed that NC-Cu-2 contained 6.14 wt% nitrogen and 2.21 wt% copper. Nitrogen adsorption-desorption analysis indicated that NC-Cu-2 had a specific surface area of ​​1025 m².2 ·g -1 The average pore size is 1.2 nm. SEM and TEM analyses showed that NC-Cu-2 had no obvious porous structure. HRTEM analysis showed that copper in NC-Cu-2 mainly exists in particle form, with particle sizes ranging from 3.5 to 8.2 nm. XPS results indicated that Cu is mainly in the 0 valence state, containing a small amount of Cu. + Furthermore, there is a certain interaction between Cu and nitrogen.

[0084] Test Example 1: Comparison of the N-formylation reaction activities of different catalysts on morpholine with CO2 and H2 The catalyst NCP@NC-Cu-1 prepared in Example 1 was used to synthesize N-formylmorpholine via the N-formylation reaction of morpholine with CO2 and H2. The specific steps are as follows: 5 mL of methanol, 3 mmol of morpholine (0.2614 g), and 0.2323 g of NCP@NC-Cu-1 (1 mol% Cu, relative to the substrate) were added to a 25 mL high-pressure reactor. Then, 3.0 MPa of H2 and 2.0 MPa of CO2 were introduced, respectively. After sealing the reactor, it was kept at 150 °C for 8 hours. After the reaction, the reactor was cooled to room temperature, and the catalyst was filtered out to obtain a solution containing the product N-formylmorpholine. The filtrate was quantitatively analyzed by gas chromatography, and the yield of N-formylmorpholine was 96%. N-Formylmorpholine... 1 H NMR image as follows Figure 6 As shown.

[0085] When the above NCP@NC-Cu-1 was replaced with other catalysts, and the amount of Cu in the reaction was kept at 1 mol% (relative to the substrate), and other reaction conditions remained unchanged, the activity results of each catalyst were obtained as shown in Table 1.

[0086] Table 1 As can be seen from Table 1: The NCP@NC-Cu-1 catalyst exhibits significantly better catalytic activity than NC-Cu-1 catalysts prepared by conventional methods. This is because the catalyst possesses a three-dimensional interconnected porous structure with large pore size, along with highly dispersed copper sites. Furthermore, there is a strong interaction between Cu and N, which enhances the intrinsic activity of the active center and the diffusion of the reaction within the catalyst.

[0087] The NCP@NC-Cu-1 catalyst exhibits superior catalytic activity compared to the NCP@NC-Cu-2 catalyst. This is because when the proportion of tetraphenylporphyrin copper(II) in the pyrolysis precursor is too high, the metallic copper in the prepared catalyst is prone to agglomeration to form nanoparticles, which leads to a decrease in the dispersion of copper-based active sites and thus reduces catalytic activity.

[0088] The NCP@NC-Cu-1 catalyst exhibits superior catalytic activity compared to NCP@NC-Cu-6 and NCP@NC-Cu-9 catalysts. This is because when the amount of KOH added is reduced or even omitted, the specific surface area of ​​the resulting catalyst decreases significantly, the pores become easily blocked, and metallic copper is easily embedded, hindering the effective contact between the reactants and the catalytic active centers, ultimately resulting in a significant reduction in catalytic activity.

[0089] The catalytic activity of NCP@NC-Cu-1 catalyst is significantly better than that of NCP@NC-Cu-11 catalyst. The reason is that when the pyrolysis temperature rises to 900℃, the metallic copper in the catalyst is prone to surface migration and agglomeration, forming a small number of copper nanoparticles, which reduces the dispersion of copper-based active sites and thus affects the catalytic activity.

[0090] The catalytic activity of NC-Cu-1 catalyst was significantly better than that of NC-Cu-2, indicating that the types of nitrogen and copper sources have a significant regulatory effect on catalytic activity. The difference in activity between the two is most likely due to the different nitrogen coordination environments around the active center Cu. When tetraphenylporphyrin copper(II) is used as a precursor for pyrolysis, an enriched nitrogen coordination structure can be constructed in situ at the Cu site, thereby improving the catalytic activity more efficiently.

[0091] Test Example 2: Cyclic Stability of NCP@NC-Cu-1 Catalyst The synthesis of N-formylmorpholine via the N-formylation reaction of morpholine with CO2 and H2 was used as a model reaction to test the recycling performance of the catalyst NCP@NC-Cu-1 prepared in Example 1. The specific steps are as follows: 5 mL of methanol, 3 mmol of morpholine (0.2614 g), and 0.2323 g of NCP@NC-Cu-1 (1 mol% Cu, relative to the substrate) were added to a 25 mL high-pressure reactor. Then, 3.0 MPa of H2 and 2.0 MPa of CO2 were introduced, respectively. After sealing the reactor, it was placed at 150 °C for 8 hours. After the reaction, the reactor was cooled to room temperature. The catalyst was filtered, washed three times with methanol, and dried under vacuum at 40 °C for 12 hours before being directly used in the next catalytic cycle. The filtrate was quantitatively analyzed by gas chromatography. The catalytic performance of the recovered catalyst was tested under the same reaction conditions, and the catalyst was recycled a total of 10 times. The results are shown in Table 2. After 10 cycles, the yield remained above 90%, indicating that the prepared NCP@NC-Cu-1 has good cycling stability. Furthermore, the loss of catalyst activity can be partially attributed to the unavoidable physical loss of the catalyst during the cycling process.

[0092] Table 2 Test Example 3: Performance of NCP@NC-Cu-1 in catalyzing the N-formylation of other amines In Test Example 1, the reaction substrate morpholine (3 mmol) was replaced with an equimolar amount of another amine (3 mmol). The reaction conditions, including catalyst (NCP@NC-Cu-1, 0.2323 g), reaction temperature (150 ℃), reaction solvent (methanol, 5 mL), and reaction pressure (3.0 MPa H2 and 2.0 MPa CO2), remained unchanged. Only the reaction time was changed according to actual needs. The reaction activity results are shown in Table 3.

[0093] Table 3 The results in Table 3 show that the NCP@NC-Cu-1 catalyst has good substrate versatility.

[0094] It should be noted that the performance of the NCP@NC-Cu-2 to NCP@NC-Cu-11 catalysts is not significantly different from that of the NCP@NC-Cu-1 catalyst in Example 1.

[0095] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a porous carbon-supported copper catalyst, characterized in that, Includes the following steps: Tetraphenylporphyrin copper(II) and tetraphenylporphyrin were mixed, chloroform was added, and the mixture was stirred until homogeneous to obtain a tetraphenylporphyrin copper(II)-tetraphenylporphyrin chloroform mixed solution; Three-dimensional interconnected ordered porous carbon was added to the tetraphenylporphyrin copper(II)-tetraphenylporphyrin chloroform mixed solution, stirred for adsorption, rotary evaporated, and vacuum dried to obtain a three-dimensional interconnected ordered porous carbon intermediate co-adsorbed with tetraphenylporphyrin copper(II) and tetraphenylporphyrin. An alkaline solution was obtained by adding an alkali to methanol and stirring until homogeneous. The three-dimensional interconnected ordered porous carbon intermediate was then added to the alkaline solution, stirred, and then rotary evaporated and vacuum dried to obtain a three-dimensional interconnected ordered porous carbon precursor adsorbed with tetraphenylporphyrin copper(II), tetraphenylporphyrin and an alkaline component. The three-dimensional interconnected ordered porous carbon precursor was subjected to programmed temperature pyrolysis in a nitrogen atmosphere. The resulting product was washed with water and dried to obtain the porous carbon-supported copper catalyst.

2. The method for preparing the porous carbon-supported copper catalyst according to claim 1, characterized in that, The molar ratio of the tetraphenylporphyrin copper(II) to the tetraphenylporphyrin is 1:(0.5~10).

3. The method for preparing the porous carbon-supported copper catalyst according to claim 1, characterized in that, The total mass ratio of the alkali to tetraphenylporphyrin copper(II) and tetraphenylporphyrin is (0.5~2):

1.

4. The method for preparing the porous carbon-supported copper catalyst according to claim 3, characterized in that, The alkali is selected from KOH or NaOH.

5. The method for preparing the porous carbon-supported copper catalyst according to claim 1, characterized in that, The total mass ratio of the three-dimensional interconnected ordered porous carbon to tetraphenylporphyrin copper(II) and tetraphenylporphyrin is (1~5):

1.

6. The method for preparing the porous carbon-supported copper catalyst according to claim 1, characterized in that, The temperature of the programmed pyrolysis treatment is 600~900℃, and the time is 2h.

7. A porous carbon-supported copper catalyst, characterized in that, It is prepared according to any one of claims 1 to 6.

8. The application of the porous carbon-supported copper catalyst as described in claim 7 in the N-formylation reaction of amines with CO2 and H2 to prepare formamide.

9. The application according to claim 8, characterized in that, The amine is selected from morpholine, p-toluidine, diethylamine, n-hexylamine, N-ethylpiperazine, benzylamine, or tetrahydroisoquinoline.

10. A method for preparing formamide by catalytic N-formylation reaction of amines with CO2 and H2, characterized in that, The process includes the following steps: adding 5 mL of methanol, 3 mmol of amine, and the porous carbon-supported copper catalyst as described in claim 7 to a high-pressure reactor, then charging it with 3.0 MPa of H2 and 2.0 MPa of CO2, sealing the high-pressure reactor, and reacting at 150 °C for 8 to 15 hours.

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