Oxygen reduction and carbon dioxide reduction electrocatalysts and methods of making and using the same

Abstract

This invention relates to the field of electrocatalytic material preparation technology, and particularly to an oxygen reduction and carbon dioxide reduction electrocatalyst, its preparation method, and its applications. Using ZIF-8 as a framework, and employing dinonanoyl iron and copper phthalocyanine as metal sources, a tandem bifunctional electrocatalyst with ORR and CO2RR is prepared via high-temperature calcination. This material exhibits both ORR activity comparable to traditional Fe-N-C materials, and its oxygen reduction performance in alkaline media surpasses that of Pt-based catalysts, possessing higher half-wave potential and stability; it also exhibits highly selective CO2RR activity. The preparation method is simple, widely applicable, and structurally adaptable to various reaction scenarios, making it suitable for applications in metal-gas batteries.

Description

Technical Field

[0001] This invention relates to the field of electrocatalytic material preparation technology, and in particular to an oxygen reduction and carbon dioxide reduction electrocatalyst, its preparation method, and its application. Background Technology

[0002] Although noble metal-based catalysts such as platinum (Pt), ruthenium (Ru), and iridium (Ir) exhibit excellent catalytic activity in the oxygen reduction reaction (ORR), their high cost limits their widespread application. Therefore, researchers have turned their attention to lower-cost transition metal-based compounds and conducted extensive research on their electrocatalytic performance. However, the performance of these catalysts remains unsatisfactory. Improving the atom utilization of the active component (usually the active metal) is considered a direct way to improve catalytic efficiency. Theoretically, shrinking the metal active component to the single-atom scale can maximize the surface atom utilization of the metal heterogeneous catalyst to 100%, thus becoming an effective strategy to improve catalyst activity and selectivity. Iron single-atom catalysts (Fe-SACs), represented by Fe-NC, are widely used in the ORR due to their high atom utilization, tunable structure, and excellent activity, but their performance in the electrocatalytic carbon dioxide reduction reaction is unsatisfactory. Therefore, developing general-purpose bifunctional catalysts that can simultaneously and efficiently catalyze multiple reactions is particularly important.

[0003] Electrocatalytic carbon dioxide reduction (CO2RR) technology offers the possibility of achieving a closed-loop artificial carbon cycle. Its key advantages include: (1) another form of storage and utilization of clean energy; (2) mild reaction conditions; and (3) the ability to convert greenhouse gases into clean fuels by controlling the catalyst. However, electrocatalytic carbon dioxide reduction technology still faces many challenges and limitations in practical applications, mainly in the following aspects: (1) high reaction energy barrier: CO2 molecules have thermodynamic stability (dissociation energy as high as 760 kJ / mol). -1(1) A high overpotential is required to activate and convert it into a key intermediate. This step is heavily dependent on the intrinsic properties of the electrocatalyst and is the main bottleneck of the entire reaction. (2) Complex reaction path: The process involves multiple electron-proton coupling transfers, resulting in a wide variety of reduction products and making it difficult to accurately control the selectivity of the target product. (3) Prominent competing reactions: In conventional aqueous electrolytes, the hydrogen evolution reaction, as the main side reaction, competes with the CO2 reduction reaction for charge and reaction sites, thereby significantly reducing the Faraday efficiency of the target product. (4) Performance indicators are not up to standard: The current system still has significant deficiencies in key performance, especially the selectivity of multi-carbon products, the current density required for industrial use, and the single-pass conversion rate of CO2 are all at a low level. Therefore, it is essential to develop high-performance, high-selectivity, and high-stability electrocatalysts to achieve efficient CO2 conversion. Among all the metal-based catalysts used, Cu is the most reported to be able to reduce CO2 to C1 products and CO2 to C2 products. 2+ The product is a metal. However, regardless of the product, obtaining a specific product with high selectivity still faces significant challenges.

[0004] Therefore, the existing technology still needs further improvement and enhancement. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to couple Fe-NC and Cu-NC in series by coupling single atoms, so that they can simultaneously have the dual functions of ORR and CO2RR electrocatalyst.

[0006] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, a method for preparing an oxygen reduction and carbon dioxide reduction electrocatalyst, comprising: Dinonyl iron carbonyl and zinc nitrate hexahydrate were dispersed in methanol solution to obtain the first solution; copper phthalocyanine and 2-methylimidazole were dispersed in methanol solution to obtain the second solution. The first solution and the second solution are mixed to obtain a mixture; The mixture was centrifuged and dried to obtain a catalyst precursor; The obtained catalyst precursor was heat-treated in an inert atmosphere to obtain the bifunctional electrocatalyst; the heat treatment temperature was 800~1000 ℃.

[0007] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The purpose and beneficial effects of the present invention can be better achieved and realized through the following preferred technical solutions.

[0008] As a preferred technical solution, in the preparation method of the oxygen reduction and carbon dioxide reduction electrocatalyst, the mass ratio of the dinonylcarbonyl iron to the copper phthalocyanine is 1:1.4~1.8.

[0009] As a preferred technical solution, in the preparation method of the oxygen reduction and carbon dioxide reduction electrocatalyst, the mass ratio of 2-methylimidazole to copper phthalocyanine is 104~124:1.

[0010] As a preferred technical solution, in the preparation method of the oxygen reduction and carbon dioxide reduction electrocatalyst, the mass ratio of 2-methylimidazole to dinonylcarbonyl iron is 160~180:1.

[0011] As a preferred technical solution, the method for preparing the oxygen reduction and carbon dioxide reduction electrocatalysts involves mixing the first solution and the second solution, and then stirring the mixture for 8-14 hours at a speed of 500-600 rpm using a magnetic stirrer to obtain a mixture.

[0012] As a preferred technical solution, the preparation method, wherein the catalyst precursor is heat-treated in an inert atmosphere to obtain the bifunctional electrocatalyst, comprises: After grinding, the catalyst precursor is transferred to a ceramic boat. The ceramic boat containing the catalyst precursor is placed in a heating device and heated at 2-6 °C for 1 minute under a nitrogen atmosphere. -1 The oxygen reduction and carbon dioxide reduction electrocatalysts were obtained by heating the catalysts at a heating rate of 800~1000 °C.

[0013] Beneficial Effects: Compared with existing technologies, the preparation method provided by this invention uses ZIF-8 as a framework and dinonanoyl iron and copper phthalocyanine as metal sources, respectively, to prepare a tandem bifunctional electrocatalyst with ORR and CO2RR by high-temperature calcination. This material possesses both ORR activity comparable to traditional Fe-NC materials, and its oxygen reduction performance in alkaline media surpasses that of Pt-based catalysts, exhibiting higher half-wave potential and stability; and highly selective CO2RR activity. The preparation method is simple, widely applicable, and structurally adaptable to various reaction scenarios, making it suitable for applications in metal-gas batteries. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the preparation method of the bifunctional electrocatalyst provided in Example 1 of the present invention; Figure 2 is a scanning electron microscope image of the bifunctional electrocatalyst provided in Example 1 of the present invention; Figure 3 This is a transmission electron microscope image of the bifunctional electrocatalyst provided in Example 1 of the present invention; Figure 4 is an aberration-corrected transmission electron microscope image of the bifunctional electrocatalyst provided in Example 1 of the present invention. Figure 5 These are high-angle annular dark-field transmission electron microscope images and corresponding elemental diagrams of the bifunctional electrocatalyst provided in Example 1 of this invention. Figure 6 The XRD patterns of the CuN4 / Fe2N6-NC, Fe2N6-NC, and CuN4-NC catalysts provided by this invention are shown below. Figure 7 Raman spectra of the CuN4 / Fe2N6-NC, Fe2N6-NC, and CuN4-NC catalysts provided by this invention; Figure 8 This is a linear voltammetry test graph at an ORR speed of 1600 rpm; Figure 9 The stability of the electrocatalyst in an oxygen-saturated 0.1 M KOH solution was tested using accelerated aging tests, and the test results are shown in the figure. Figure 10 This is a schematic diagram of the Faradaic efficiency of CuN4 / Fe2N6-NC, Fe2N6-NC, and CuN4-NC catalysts for the electrochemical reduction of carbon dioxide to CO. Figure 11 This is a schematic diagram of the current density of CuN4 / Fe2N6-NC, Fe2N6-NC, and CuN4-NC catalysts used for the electrochemical reduction of carbon dioxide to CO. Figure 12 This is a stability test of CuN4 / Fe2N6-NC in electrocatalytic carbon dioxide; Figure 13 This is a diagram showing the open-circuit voltage of an assembled zinc-air battery tested with a multimeter. Figure 14 This is a diagram showing a zinc-air battery charging a mobile phone. Figure 15 This is the power density diagram of CuN4 / Fe2N6-NC; Figure 16 This is the power density diagram of Pt / C+RuO2; Figure 17 This is a chart showing the stability of charge-discharge cycles. Detailed Implementation

[0015] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other. The invention will now be described in detail with reference to the embodiments. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0016] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form as well. Furthermore, it should be understood that when the terms "comprising" and / or "package" are used in this specification… When "includes", it indicates the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0017] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. Techniques, methods, and apparatus known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and apparatus should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0018] like Figure 1 As shown, the present invention provides a method for preparing a bifunctional electrocatalyst, comprising the following steps: Step S10: Disperse dinonylcarbonyl iron and zinc nitrate hexahydrate in methanol solution to obtain the first solution; disperse copper phthalocyanine and 2-methylimidazole in methanol solution to obtain the second solution.

[0019] Specifically, firstly, iron dinonanocarbonyl and zinc nitrate hexahydrate can be dissolved in methanol to obtain an iron-containing solution, i.e., the first solution; then, copper phthalocyanine and 2-methylimidazole can be dissolved in methanol to obtain a copper-containing solution, i.e., the second solution. Both solutions are then subjected to ultrasonic treatment to ensure more uniform mixing.

[0020] Step S20: Mix the first solution with the second solution to obtain a mixture.

[0021] Specifically, the first solution and the second solution are mixed and stirred for 8-14 hours at 500-600 rpm using a magnetic stirrer to obtain a mixture.

[0022] Step S30: Centrifuge and dry the mixture to obtain the catalyst precursor.

[0023] Specifically, the mixture was centrifuged three times with ethanol to obtain blue Fe2(CO)9@CuPc-ZIF-8 powder (catalyst precursor), which was then dried in an oven, ground in a mortar and pestle, and then transferred to a porcelain boat.

[0024] Step S40: The catalyst precursor is heat-treated in an inert atmosphere to obtain the bifunctional electrocatalyst; the heat treatment temperature is 800~1000 ℃.

[0025] Specifically, a ceramic boat containing Fe2(CO)9@CuPc-ZIF-8 powder is transferred to a single-temperature zone tube furnace and heated under a nitrogen atmosphere to obtain a black powder.

[0026] This invention employs a second metal introduction strategy, introducing Fe-NC into the Cu-NC substrate. In alkaline media, its ORR performance surpasses that of commercial Pt / C benchmark catalysts, exhibiting a more positive half-wave potential and superior stability. Simultaneously, this catalyst also achieves high Faradaic efficiency and current density in electrocatalytic CO2RR. Furthermore, the preparation method is low-cost, simple, and reproducible, possessing significant potential for large-scale application.

[0027] In one implementation of the present invention, the mass ratio of dinonylcarbonyl iron to copper phthalocyanine is 1:1.4~1.8; by controlling the mass ratio of dinonylcarbonyl iron to copper phthalocyanine within the given range, the iron and copper single atoms can be coordinated to efficiently regulate ORR and CO2RR respectively.

[0028] Furthermore, the mass ratio of 2-methylimidazole to copper phthalocyanine is 104~124:1. By controlling the mass of 2-methylimidazole and copper phthalocyanine within the given range, the interaction between metallic copper and the support can be adjusted, thereby increasing the number of active sites.

[0029] Furthermore, the mass ratio of 2-methylimidazole to dinonylcarbonyl iron is 160~180:1. By controlling the mass of 2-methylimidazole and dinonylcarbonyl iron within the given range, the interaction between metallic iron and the support can be adjusted, thereby increasing the number of active sites.

[0030] The following specific preparation examples will further explain and illustrate the CuN4 / Fe2N6-NC type oxygen reduction and carbon dioxide reduction electrocatalysts and their preparation methods provided by the present invention.

[0031] Example 1 11 mg of dinonylcarbonyl iron and 1.19 g of zinc nitrate hexahydrate were dissolved in 40 mL of methanol to form the first solution. 16 mg of copper phthalocyanine and 1.98 g of 2-methylimidazole were dissolved in 20 mL of methanol to form the second solution. The first and second solutions were sonicated for 20 min. The second solution was then quickly poured into the first solution, and sonication continued for another 10 min. Finally, the mixture was stirred for 12 h using a magnetic stirrer at 500-600 rpm.

[0032] The above mixture was centrifuged and washed three times with ethanol to obtain blue Fe2(CO)9@CuPc-ZIF-8 powder, which was then dried in an oven at 60 °C for 12 h, and then ground in a mortar for 40 min before being transferred to a porcelain boat.

[0033] A ceramic boat containing Fe2(CO)9@CuPc-ZIF-8 powder was placed in a single-temperature zone tube furnace and heated at 5 °C for 1 minute under a nitrogen atmosphere. -1 The temperature was increased to 900 °C and held for 3 h to obtain a black powder. The catalyst was named CuN4 / Fe2N6-NC.

[0034] Comparative Example 1 11 mg of dinonylcarbonyl iron and 1.19 g of zinc nitrate hexahydrate were dissolved in 40 mL of methanol to form the first solution; 1.98 g of 2-methylimidazole was dissolved in 20 mL of methanol to form the second solution. The first and second solutions were sonicated for 20 min, and then the second solution was quickly poured into the first solution, followed by sonication for another 10 min. Finally, the mixture was stirred for 12 h using a magnetic stirrer at 500-600 rpm.

[0035] The above mixture was centrifuged and washed three times with ethanol to obtain a pale yellow Fe2(CO)9@ZIF-8 powder, which was then dried in an oven at 60 °C for 12 h, and then ground in a mortar for 40 min before being transferred to a porcelain boat.

[0036] A ceramic boat containing Fe2(CO)9@ZIF-8 powder was placed in a single-temperature zone tube furnace and heated at 5 °C for 1 minute under a nitrogen atmosphere. -1 The temperature was increased to 900 °C and held for 3 h to obtain a black powder. The catalyst was named Fe2N6-NC.

[0037] Comparative Example 2 1.19 g of zinc nitrate hexahydrate was dissolved in 40 mL of methanol to form the first solution. 16 mg of copper phthalocyanine and 1.98 g of 2-methylimidazole were dissolved in 20 mL of methanol to form the second solution. The first and second solutions were sonicated for 20 min. The second solution was then quickly poured into the first solution, and sonication continued for another 10 min. Finally, the mixture was stirred for 12 h using a magnetic stirrer at 500-600 rpm.

[0038] The above mixture was centrifuged and washed three times with ethanol to obtain blue CuPc-ZIF-8 powder, which was then dried in an oven at 60 °C for 12 h, and then ground in a mortar for 40 min before being transferred to a porcelain boat.

[0039] A ceramic boat containing CuPc-ZIF-8 powder was placed in a single-temperature zone tube furnace and heated at 5 °C for 1 minute under a nitrogen atmosphere. -1 The temperature was increased to 900 °C and held for 3 h to obtain a black powder. The catalyst was named CuN4-NC.

[0040] The catalysts synthesized in the above examples were characterized as follows: The synthesized electrocatalyst CuN4 / Fe2N6-NC was observed using scanning electron microscopy, transmission electron microscopy, and aberration-corrected transmission electron microscopy. Scanning electron microscopy images (…) Figure 2 The transmission electron microscope image shows a typical dodecahedral morphology. Figure 3 It shows its distinct hollow carbon structure. Aberration-corrected transmission electron microscopy image ( Figure 4 The presence of distinct bright spots indicates that Fe / Cu atoms are dispersed in the carbon structure as single atoms. High-angle annular dark-field transmission electron microscopy image and corresponding elemental map ( Figure 5 The uniform distribution of C, N, Cu, and Fe elements was confirmed. XRD patterns of CuN4 / Fe2N6-NC, Fe2N6-NC, and CuN4-NC catalysts are shown. Figure 6 The data shows only two distinct carbon peaks, with no indication of the presence of Fe or Cu phases, indirectly confirming that Fe and Cu may exist in single-atom form. Raman spectra of CuN4 / Fe2N6-NC, Fe2N6-NC, and CuN4-NC catalysts ( Figure 7 D represents the defect degree, and G represents the graphitization degree. Their ratio illustrates the relative situation of defects and graphitization. Specifically, for CuN4 / Fe2N6-NC, I... D / I G The highest value indicates that the introduction of copper is beneficial to defect formation, and the increase in defect carbon helps expose reactive sites, thus strongly promoting subsequent electrochemical reactions. Electrochemical testing: In this invention, the oxygen reduction reaction (ORR) test method is as follows: ORR testing is performed using a Chenhua 760e electrochemical workstation and a rotating disk electrode. 2 mg of the electrocatalyst prepared in Example 1 is weighed and dispersed in a mixed solution containing 100 mL of deionized water, 100 mL of ethanol, and 10 μL of 5 wt% Nafion perfluorosulfonic acid resin. The dispersion is sonicated for 40 min to obtain catalyst ink. 2 μL of this ink is dropped onto the surface of the rotating disk electrode and dried at room temperature to obtain the catalyst electrode (catalyst loading is 0.27 mg / cm³). -2 The electrode was used as the working electrode, the electrolyte was an oxygen-saturated 0.1 M KOH solution, the counter electrode was a carbon rod, and the reference electrode was a saturated calomel electrode. LSV testing was performed at 1600 rpm, and the platinum-carbon catalyst (Pt / C) used was 20% Pt / C from JM Company. The linear voltammetry graph for ORR at 1600 rpm is shown below. Figure 8 As shown, the half-wave potential of CuN4 / Fe2N6-NC is 0.92 V, that of Fe2N6-NC is 0.89 V, that of CuN4-NC is 0.87 V, and that of Pt / C is 0.86 V, indicating that the prepared CuN4 / Fe2N6-NC catalyst has high catalytic activity for the oxygen reduction reaction.

[0041] In this invention, the stability of the electrocatalyst in an oxygen-saturated 0.1 MkOH solution was assessed using accelerated aging tests. The accelerated aging test method involved continuous scanning cyclic voltammetry at 100 mV / s in KOH solution. -1 Accelerated aging tests were performed for 2000-10000 cycles within a potential range of 0.6-1.1V. The results are as follows: Figure 9 As shown, after 10,000 cycles, the half-wave potential and current density of the catalyst CuN4 / Fe2N6-NC remained almost unchanged, while the current density of Pt / C decreased by 4.3% and the half-wave potential decreased by 6 mV after 2,000 cycles, indicating that the catalyst CuN4 / Fe2N6-NC has good catalytic stability.

[0042] In this invention, the electrocatalytic carbon dioxide reduction test method is as follows: 5 mg of the catalyst prepared in Example 1 is dispersed in a solution containing 250 mL of ethanol and 250 mL of deionized water, and 25 μL of 5wt% Nafion perfluorosulfonic acid resin solution is added. After sonication for 1 h, catalyst ink is obtained and coated onto a 2×1 cm plate. 2 The coating area is 1×1cm on the hydrophobic carbon paper. 2 (Catalyst loading: 0.95 mg cm⁻¹) -2The carbon paper was dried in an oven at 60 °C for 12 h. It was then clamped onto a Pt electrode holder as an electrode, with a carbon rod as the counter electrode and an Ag / AgCl electrode as the reference electrode. Electrocatalytic carbon dioxide reduction was tested in an H-type electrolytic cell filled with a 0.5 M KHCO3 solution saturated with carbon dioxide at a specific voltage. The cathode gas was analyzed online using a gas chromatograph (Shimadzu GC-2014C). All tests were conducted at room temperature and pressure. The catalyst's CO Faradaic efficiency is as follows: Figure 10 As shown, CuN4 / Fe2N6-NC achieves a FECO conversion rate of 90.2% at -0.7 V, the highest among a series of materials. The current density diagram corresponding to CO production by the catalyst is shown below. Figure 11 As shown, the current density of CuN4 / Fe2N6-NC is the highest among a series of materials, indicating that CuN4 / Fe2N6-NC material has the highest catalytic activity for converting CO2 to CO. The CO2 electrocatalytic reduction stability test graph is shown below. Figure 12 As shown, during the 10-hour stability test, the CO Faraday efficiency remained above 85%, and the current density remained almost unchanged.

[0043] In this invention, the zinc-air battery is tested using a self-made alkali-resistant plastic mold (length: 5 cm, width: 5 cm). 5 mg of the catalyst prepared in Example 1 is dispersed in a solution containing 250 mL of ethanol and 250 mL of deionized water, and 25 μL of a 5wt% Nafion perfluorosulfonic acid resin solution is added. The mixture is sonicated for 1 h to obtain a uniform catalyst ink. All the catalyst ink is coated in batches onto the central ring (radius: 1 cm) of carbon paper (length: 6 cm, width: 3 cm) and dried in an oven at 60 °C for 12 h.

[0044] The method for preparing the ink for the control sample Pt / C + ruthenium dioxide (RuO2) is as follows: 2.5 mg Pt / C and 2.5 mg RuO2 were dispersed in a solution containing 250 mL ethanol and 250 mL deionized water, and 25 μL of 5wt% Nafion perfluorosulfonic acid resin solution was added. The mixture was sonicated for 1 h to obtain a uniform catalyst ink. Then, all the catalyst inks were coated in batches onto the central ring (radius 1 cm) of carbon paper (6 cm long and 3 cm wide) and dried in an oven at 60 ℃ for 12 h.

[0045] A self-made zinc-air battery device was assembled using zinc foil (6 cm long, 3 cm wide, and 0.5 mm thick) as the anode, carbon paper-supported catalyst as the air cathode, and 6.0 M KOH as the electrolyte, and subsequent tests were conducted. The charge-discharge polarization curves of the zinc-air battery were measured using LSV curves on a CHI760E electrochemical workstation, and the power density was calculated. In the LAND testing system, 3.0 mA·cm⁻¹ -2 The charge-discharge cycle stability of the battery was tested at a specific current density. The open-circuit voltage of the assembled zinc-air battery was tested using a multimeter. Figure 13 As shown, its open-circuit voltage is 1.494 V. The assembled zinc-air battery is then used to charge the mobile phone, as follows: Figure 14 As shown, this confirms the potential application capability of this battery in energy storage devices. The power density diagram of the catalyst is shown below. Figure 15 As shown, the power density is 203.3 mW / cm². 2 The power density diagram of Pt / C+RuO2 is shown below. Figure 16 As shown, its power density is 121.8 mW / cm². 2 This indicates that the prepared CuN4 / Fe2N6-NC catalyst outperforms currently available commercial catalysts. Its charge-discharge cycle stability is as follows: Figure 17 As shown, the stabilization time is 300 h.

[0046] In summary, this invention discloses a method for preparing a bifunctional electrocatalyst for oxygen reduction and carbon dioxide reduction, and its application. The method for preparing the bifunctional electrocatalyst for oxygen reduction and carbon dioxide reduction of this invention includes the following steps: (1) using 2-methylimidazole, zinc nitrate hexahydrate, copper phthalocyanine, dinonylcarbonyl iron, and methanol as raw materials, after stirring at room temperature, the resulting product is centrifuged, washed, and dried to obtain a catalyst precursor Fe2(CO)9@CuPc-ZIF-8; (2) calcining the catalyst precursor Fe2(CO)9@CuPc-ZIF-8 obtained in step 1 at high temperature in an inert atmosphere to obtain CuN4 / Fe2N6-NC, which exhibits high catalytic activity for both oxygen reduction and carbon dioxide reduction reactions. This method has low preparation cost, simple process, and good reproducibility; the oxygen reduction performance of this catalyst in alkaline media exceeds that of Pt-based catalysts, possessing higher half-wave potential and stability; simultaneously, it also exhibits high Faradaic efficiency and current density in the electrocatalytic carbon dioxide reduction reaction.

[0047] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A method for preparing an oxygen reduction and carbon dioxide reduction electrocatalyst, characterized in that, include: The first solution was obtained by dispersing dinonylcarbonyl iron and zinc nitrate hexahydrate in a methanol solution. Copper phthalocyanine and 2-methylimidazole were dispersed in a methanol solution to obtain a second solution; The first solution and the second solution are mixed to obtain a mixture; The mixture was centrifuged and dried to obtain a catalyst precursor; The catalyst precursor is heat-treated in an inert atmosphere to obtain the oxygen reduction and carbon dioxide reduction electrocatalysts. The heat treatment temperature is 800~1000 ℃; The mass ratio of the dinonylcarbonyl iron to the copper phthalocyanine is 1:1.4~1.

8.

2. The method for preparing the oxygen reduction and carbon dioxide reduction electrocatalyst according to claim 1, characterized in that, The mass ratio of the dinonylcarbonyl iron to the zinc nitrate hexahydrate is 1:100~120.

3. The method for preparing the oxygen reduction and carbon dioxide reduction electrocatalyst according to claim 1, characterized in that, The volume of the methanol solution is 20-40 mL.

4. The method for preparing the oxygen reduction and carbon dioxide reduction electrocatalyst according to claim 1, characterized in that, The catalyst precursor is heat-treated in an inert atmosphere to obtain the oxygen reduction and carbon dioxide reduction electrocatalyst, comprising: The catalyst precursor was ground and then transferred to a ceramic boat. The ceramic boat containing the catalyst precursor was placed in a tube furnace and heated at 2-6 °C for 1 minute under a nitrogen atmosphere. -1 The temperature was increased to 800~1000 °C at a heating rate to obtain an electrocatalyst for oxygen reduction and carbon dioxide reduction.

5. The method for preparing the oxygen reduction and carbon dioxide reduction electrocatalyst according to claim 1, characterized in that, The mass ratio of 2-methylimidazole to copper phthalocyanine is 104~124:

1.

6. The method for preparing the oxygen reduction and carbon dioxide reduction electrocatalyst according to claim 1, characterized in that, The mass ratio of 2-methylimidazole to dinonylcarbonyl iron is 160~180:

1.

7. An electrocatalyst for oxygen reduction and carbon dioxide reduction, characterized in that, The oxygen reduction and carbon dioxide reduction electrocatalysts are prepared using any one of the preparation methods described in claims 1 to 6.

8. The application of the oxygen reduction and carbon dioxide reduction electrocatalyst of claim 7 in the catalytic reaction of carbon dioxide.

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