Preparation method of copper oxide / scandium oxide composite nanoelectrocatalyst and application of copper oxide / scandium oxide composite nanoelectrocatalyst in electrocatalytic carbon monoxide reduction

Abstract

This invention belongs to the field of energy catalysis technology, specifically a method for preparing a copper oxide / scandium oxide composite nano-electrocatalyst and its application in the electrocatalytic reduction of carbon monoxide. A copper source and a scandium source are mixed with a citric acid solution to obtain a clear solution; the solution is stirred and heated to obtain a sol; the sol is gradually evaporated and heated to obtain a gel precursor; the gel precursor is calcined in air to obtain the copper oxide / scandium oxide composite nano-electrocatalyst. This invention, through the introduction of the rare-earth metal scandium oxide, exhibits high acetic acid selectivity and stability in the electrocatalytic reduction of carbon monoxide. In a conventional gas diffusion three-electrode flow cell system, this catalyst can achieve a maximum acetic acid Faradaic efficiency of 83.7%; this catalyst can achieve high acetic acid Faradaic efficiency at 100 cm⁻¹. 2 In the membrane electrode assembly, it can operate continuously and stably for 2400 hours with a total current of 15A, while maintaining an acetic acid faradaic efficiency of over 80%.

Description

Technical Field

[0001] This invention belongs to the field of energy catalysis technology, specifically relating to a method for preparing a copper oxide / scandium oxide composite nanocatalyst and its application in the electrocatalytic reduction of carbon monoxide. Background Technology

[0002] The research on the electrocatalytic reduction of carbon monoxide to produce acetic acid is of great significance in the fields of energy conversion and chemical synthesis. This technology can not only provide a new pathway for the resource utilization of carbon dioxide, but also offer a more sustainable alternative for the production of acetic acid. The electrocatalytic synthesis of acetic acid involves multiple intermediate products (such as CO, ethylene, and methane), and improving the selectivity of acetic acid is a key issue. Especially in the electrocatalytic process, a balance must often be struck between the production of acetic acid and the formation of other products. Existing catalysts often suffer from poor selectivity, leading to the formation of byproducts, which not only reduces the yield of acetic acid but may also result in resource waste and inefficiency. Electrocatalytic reactions are usually carried out under conditions of high current density and strong corrosiveness, requiring catalysts with high stability. However, most catalysts are prone to degradation, deactivation, or corrosion under these harsh conditions. The stability of the catalyst directly affects the long-term operating efficiency and economy of the electrocatalytic process, especially in practical industrial applications, where catalyst stability becomes a significant challenge.

[0003] Scandium oxide can form good interfaces with various metals (such as palladium, platinum, nickel, and ruthenium). When used as a support, scandium oxide enhances the dispersibility of metal catalysts and improves the size distribution of metal particles, thereby increasing catalyst activity. Furthermore, the synergistic effect between scandium oxide and metals may further improve the catalyst's reactivity. Meanwhile, scandium oxide exhibits strong corrosion resistance in both acidic and alkaline environments. This allows it to maintain good stability under extreme reaction conditions, especially in strong acid, strong alkali, or high-oxygen environments. This corrosion resistance enables scandium oxide to be used for extended periods in highly corrosive reaction systems, enhancing catalyst lifespan and reaction stability.

[0004] In view of this, it is necessary to provide a method for preparing copper oxide / scandium oxide composite nano-electrocatalysts to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing copper oxide / scandium oxide composite nano-electrocatalyst and its application in the electrocatalytic reduction of carbon monoxide, thereby improving the selectivity and stability of the electrocatalytic reduction of carbon monoxide to acetic acid.

[0006] To achieve the above objectives, the present invention provides a method for preparing a copper oxide / scandium oxide composite nanocatalyst, comprising the following steps: S1. Mix the copper source and scandium source with citric acid solution to obtain a clear solution; S2. Stir the clarified solution and heat it to obtain a mixed sol; S3. The mixed sol is gradually evaporated under heating conditions to obtain a gel precursor; S4. The gel precursor is calcined in air to obtain a copper oxide / scandium oxide composite nano-electrocatalyst.

[0007] Furthermore, in step S1, the molar ratio of the copper source to the scandium source is 1:(10-100), preferably 1:(20-80). A molar ratio of 1:20 for the copper source to the scandium source exhibits the highest selectivity for acetic acid. Copper salts and scandium salts are preferred as the copper source and scandium source, with copper nitrate trihydrate and anhydrous scandium nitrate being more effective.

[0008] Furthermore, the solvent for the citric acid solution is anhydrous ethanol, and the concentration of citric acid is 0.02-0.06 g / mL; The total mass of the copper source and scandium source to the citric acid solution has a mass-to-volume ratio of 0.022 g to 0.024 g: 1 mL.

[0009] Furthermore, in step S2, the heating is carried out at 100-150°C for 1-5 hours.

[0010] Furthermore, in step S3, the heating is carried out at 180-220°C for 1-5 hours.

[0011] Furthermore, the calcination temperature is 750-850℃, the time is 6-12 h, and the heating rate is 5-10℃ / min.

[0012] The present invention also provides a copper oxide / scandium oxide composite nanocatalyst, which is obtained by the preparation method described above.

[0013] This invention also provides the application of a copper oxide / scandium oxide composite nanocatalyst in the electrocatalytic reduction reaction of carbon monoxide.

[0014] Further, the method includes: preparing the copper oxide / scandium oxide composite nano-electrocatalyst into a dispersion, then spraying it onto a gas diffusion electrode, and then assembling it into a three-electrode gas diffusion electrolytic cell or a membrane electrode electrolytic cell, and introducing carbon monoxide to carry out the electrocatalytic reaction.

[0015] Furthermore, the amount of copper oxide / scandium oxide composite nano-electrocatalyst supported on the gas diffusion electrode is 0.5-2 mg / cm³. 2 The dispersion also contains Nafion solution.

[0016] Furthermore, the products of the electrocatalytic reaction include one or more of acetic acid, ethanol, and ethylene, and the mass content of acetic acid is greater than 60%.

[0017] In summary, compared with the prior art, the above-described technical solutions conceived by this invention mainly possess the following technical advantages: 1. This invention constructs a copper oxide composite nanocatalyst supported on rare earth metal scandium oxide using the sol-gel method through citric acid coordination. This enhances the interaction strength between the support and the active component, improves the adsorption behavior of carbon monoxide reactants, and tightly binds copper oxide and scandium oxide nanoparticles. The strong interaction between CuO and Sc2O3 not only enhances the electrocatalyst's adsorption capacity for CO but also promotes electron transfer and the stability of reaction intermediates, thereby significantly improving the catalyst's activity and stability. Ultimately, this results in a catalyst exhibiting superior catalytic activity during the electrocatalytic reduction of carbon monoxide.

[0018] 2. The copper oxide / scandium oxide composite nano-electrocatalyst provided by this invention can significantly improve the selectivity and stability of the electrocatalytic reduction of carbon monoxide to acetic acid. In a gas diffusion three-electrode flow cell, the electrocatalyst can achieve a maximum acetic acid Faradaic efficiency of 83.7%. This catalyst can withstand 100 cm⁻¹... 2 In the membrane electrode assembly, it can operate continuously and stably for 2400 hours with a total current of 15A while maintaining a high acetic acid faradaic efficiency of over 80%, resulting in a longer service life and higher economic benefits in practical applications.

[0019] 3. The raw materials for this invention are widely available, the preparation method is simple, and it can efficiently and stably convert carbon monoxide into acetic acid, thus having broad commercial prospects. Attached Figure Description

[0020] Figure 1 This is a synthetic route diagram of the copper oxide / scandium oxide composite nanocatalyst in Example 1; Figure 2 This is the XRD pattern of the copper oxide / scandium oxide composite nanocatalyst prepared in Example 1. In the figure, 2θ refers to the diffraction angle. Figure 3 This is a transmission electron microscope image of the copper oxide / scandium oxide composite nanocatalyst prepared in Example 1; Figure 4 This is an elemental distribution image of the copper oxide / scandium oxide composite nanocatalyst prepared in Example 1. Red represents scandium, green represents oxygen, and yellow represents copper (scale bar is 200 nm). Figure 5 This is a synchrotron radiation diagram of the copper oxide / scandium oxide composite nanocatalyst prepared in Example 1; Figure 6This is a Faraday efficiency distribution diagram of the products obtained by electrocatalyzing the reduction of carbon monoxide in a three-electrode gas diffusion flow cell using the copper oxide / scandium oxide composite nanocatalyst prepared in Example 1. Figure 7 This is a diagram showing the Faraday efficiency distribution and current-potential correspondence of the products obtained by electrocatalyzing the reduction of carbon monoxide in a membrane electrode flow cell using the copper oxide / scandium oxide composite nanocatalyst prepared in Example 1. Figure 8 This is a stability diagram of the copper oxide / scandium oxide composite nanocatalyst prepared in Example 1, obtained by electrocatalyzing the reduction of carbon monoxide in a membrane electrode flow cell. Figure 9 This is a comparison chart of the performance of the copper oxide / scandium oxide composite nano-electrocatalyst prepared in Example 1 in the electrocatalytic reduction of carbon monoxide in a membrane electrode flow cell with the performance of other copper-based electrocatalyst materials. Figure 10 This is a Faraday efficiency distribution diagram of the products obtained by electrocatalyzing the reduction of carbon monoxide in a three-electrode gas diffusion flow cell using the copper oxide / scandium oxide composite nano-electrocatalyst prepared in Example 3. Figure 11 This is a Faraday efficiency distribution diagram of the products obtained by electrocatalyzing the reduction of carbon monoxide in a three-electrode gas diffusion flow cell using the copper oxide / scandium oxide composite nanocatalyst prepared in Example 4. Figure 12 This is a Faraday efficiency distribution diagram of the products obtained by electrocatalyzing the reduction of carbon monoxide in a three-electrode gas diffusion flow cell using the copper oxide / scandium oxide composite nanocatalyst prepared in Example 5. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0022] Example 1 A method for preparing copper oxide / scandium oxide composite nano-electrocatalyst, wherein copper nitrate trihydrate and anhydrous scandium nitrate are used as copper source and scandium source, respectively, and copper metal ions of different contents are introduced to modify CuO-Sc2O3 nanoparticles. Figure 1 The specific steps are as follows: 1) Dissolve 0.8 g of citric acid (CA) in 20 mL of anhydrous ethanol solution with stirring; stir thoroughly until a clear solution is obtained; 2) Weigh 24 mg of copper nitrate trihydrate (241.6 g / mol) and 0.46 g of anhydrous scandium nitrate (230.97 g / mol), respectively. Then add the copper nitrate and scandium nitrate to the clear solution obtained in step 1), stir thoroughly and heat at 150°C until a mixed sol is obtained. 3) Transfer the solution obtained in step 2) to a forced-air drying oven and gradually evaporate it at a temperature of 200 °C for 3 hours to obtain the gel precursor; 4) Place the reactants obtained in step 3) in air and heat them from room temperature to 800℃ at a heating rate of 10℃ / min. Calcinate the precursor material for 10h and allow it to cool naturally to room temperature to obtain rare earth oxide-supported CuO-Sc2O3 nanoparticles, which are high acetic acid-selective copper oxide / rare earth scandium oxide composite materials.

[0023] The structure of the CuO-Sc2O3 composite nanoparticles prepared by the above method was determined by XRD pattern obtained using X-ray diffraction. Figure 2 As shown, the CuO-Sc2O3 nanoparticles synthesized in this invention are pure phases, exhibiting separate CuO and Sc2O3 phases without any other impurities.

[0024] like Figure 3 Transmission electron microscopy images show that nanoscale CuO-Sc2O3 particles were successfully prepared, with a size of less than 100 nm and relatively uniform, and the copper oxide particles and scandium oxide particles were tightly bonded together.

[0025] like Figure 4 The elemental distribution images show that the CuO-Sc2O3 composite nanoparticles exhibit a uniform distribution of Sc, Cu, and O elements.

[0026] like Figure 5 As shown, synchrotron radiation spectroscopy tests indicate that the CuO-Sc2O3 composite nanoparticles synthesized in this invention exhibit Cu-O bonds, proving that the true active site is Cu in an oxidized state.

[0027] Example 2 The present invention provides a method for using the above-mentioned catalyst in electrocatalytic carbon monoxide reduction testing, and the specific steps are as follows: 1) The CuO-Sc2O3 nanoparticle electrocatalyst prepared in Example 1 was dispersed in a solvent, and Nafion solution was added. The dispersion was then uniformly adjusted under ultrasonic conditions. The catalyst was then sprayed layer by layer onto a gas diffusion electrode using a spraying method and dried. The catalyst loading was controlled at 1 mg / cm³. 2 , serving as the cathode for electrocatalytic reactions; 2) In a three-electrode gas diffusion electrolysis cell, carbon monoxide gas is introduced so that the carbon monoxide comes into contact with the side of the electrode that is not loaded with electrocatalyst, and the potassium hydroxide electrolyte comes into contact with the side of the electrode that is loaded with electrocatalyst. 3) Apply a negative voltage to the electrodes in the electrolytic cell assembled in step 2) and perform performance tests in the potential ranges of -0.6, -0.7, -0.8, -0.9, -1.0, -1.1, and -1.2 volts respectively.

[0028] 4) At 100 cm 2 In a membrane electrode electrolytic cell, humidified carbon monoxide gas is introduced into the cathode side to bring potassium hydroxide electrolyte into contact with the anode side, thus assembling a two-electrode membrane electrode system. 5) Apply a current of 1 to 50 amperes to the electrodes in the membrane electrode assembly in step 4) and perform performance tests sequentially.

[0029] like Figure 6 As shown, the copper oxide / scandium oxide composite nano-electrocatalyst achieved a Faraday efficiency of up to 83.7% in the electrocatalytic reduction of carbon monoxide to acetic acid in a three-electrode gas diffusion flow cell, indicating good selectivity for acetic acid.

[0030] like Figure 7 As shown, the distribution of the Faradaic efficiency of the products obtained by the electrocatalytic reduction of carbon monoxide by the copper oxide / scandium oxide composite nanocatalyst in the membrane electrode flow cell and the current-potential correspondence diagram show that the acetic acid Faradaic efficiency is 83.09% at 15 amperes.

[0031] like Figure 8 As shown, at 100 cm 2 Electrocatalytic carbon monoxide reduction in the membrane electrode flow cell exhibited stability for 2400 h (total current of 15 amperes).

[0032] like Figure 9 As shown, the catalysts of the present invention have significantly higher acetic acid Faraday efficiency and stability compared with those of the prior art.

[0033] Example 3 A method for preparing copper oxide / scandium oxide composite nano-electrocatalyst, wherein copper nitrate trihydrate and anhydrous scandium nitrate are used as copper source and scandium source, respectively, and copper metal ions of different contents are introduced to modify CuO-Sc2O3 nanoparticles. Figure 1 The specific steps are as follows: 1) Dissolve 0.8 g of citric acid (CA) in 20 mL of anhydrous ethanol solution with stirring; stir thoroughly until a clear solution is obtained; 2) Weigh 6 mg of copper nitrate trihydrate and 0.46 g of anhydrous scandium nitrate, then add copper nitrate and scandium nitrate to the clear solution obtained in step 1), stir thoroughly and heat at 150 °C until a mixed sol is obtained; 3) Transfer the solution obtained in step 2) to a forced-air drying oven and gradually evaporate it at a temperature of 200 °C for 3 hours to obtain the gel precursor; 4) Place the reactants obtained in step 3) in air and heat them from room temperature to 800℃ at a heating rate of 10℃ / min. Calcinate the precursor material for 10h and allow it to cool naturally to room temperature to obtain rare earth oxide-supported CuO-Sc2O3 nanoparticles, which are copper oxide / scandium oxide composite nano-electrocatalyst materials.

[0034] like Figure 10 As shown, the copper oxide / scandium oxide composite nanocatalyst achieved a maximum Faraday efficiency of 72.6% in the electrocatalytic reduction of carbon monoxide to acetic acid in a three-electrode gas diffusion flow cell.

[0035] Example 4 A method for preparing copper oxide / scandium oxide composite nano-electrocatalyst, wherein copper nitrate trihydrate and anhydrous scandium nitrate are used as copper source and scandium source, respectively, and copper metal ions of different contents are introduced to modify CuO-Sc2O3 nanoparticles. Figure 1 The specific steps are as follows: 1) Dissolve 0.8 g of citric acid (CA) in 20 mL of anhydrous ethanol solution with stirring; stir thoroughly until a clear solution is obtained; 2) Weigh 12 mg of copper nitrate trihydrate and 0.46 g of anhydrous scandium nitrate, then add copper nitrate and scandium nitrate to the clear solution obtained in step 1), stir thoroughly and heat at 150 °C until a mixed sol is obtained; 3) Transfer the solution obtained in step 2) to a forced-air drying oven and gradually evaporate it at a temperature of 200 °C for 3 hours to obtain the gel precursor; 4) Place the reactants obtained in step 3) in air and heat them from room temperature to 800℃ at a heating rate of 10℃ / min. Calcinate the precursor material for 10h and allow it to cool naturally to room temperature to obtain rare earth oxide-supported CuO-Sc2O3 nanoparticles, which are copper oxide / scandium oxide composite nano-electrocatalyst materials.

[0036] like Figure 11 As shown, the copper oxide / scandium oxide composite nanocatalyst achieved a maximum Faraday efficiency of 75.7% in the electrocatalytic reduction of carbon monoxide to acetic acid in a three-electrode gas diffusion flow cell.

[0037] Example 5 A method for preparing copper oxide / scandium oxide composite nano-electrocatalyst, wherein copper nitrate trihydrate and anhydrous scandium nitrate are used as copper source and scandium source, respectively, and copper metal ions of different contents are introduced to modify CuO-Sc2O3 nanoparticles. Figure 1 The specific steps are as follows: 1) Dissolve 0.8 g of citric acid (CA) in 20 mL of anhydrous ethanol solution with stirring; stir thoroughly until a clear solution is obtained; 2) Weigh 48 mg of copper nitrate trihydrate and 0.46 g of anhydrous scandium nitrate, then add copper nitrate and scandium nitrate to the clear solution obtained in step 1), stir thoroughly and heat at 150 °C until a mixed sol is obtained; 3) Transfer the solution obtained in step 2) to a forced-air drying oven and gradually evaporate it at a temperature of 200 °C for 3 hours to obtain the gel precursor; 4) Place the reactants obtained in step 3) in air and heat them from room temperature to 800℃ at a heating rate of 10℃ / min. Calcinate the precursor material for 10h and allow it to cool naturally to room temperature to obtain rare earth oxide-supported CuO-Sc2O3 nanoparticles, which are copper oxide / scandium oxide composite nano-electrocatalyst materials.

[0038] like Figure 12 As shown, the copper oxide / scandium oxide composite nanocatalyst achieved a maximum Faraday efficiency of 67.7% in the electrocatalytic reduction of carbon monoxide to acetic acid in a three-electrode gas diffusion flow cell.

[0039] In summary, this invention constructs a rare-earth metal scandium oxide-supported copper oxide composite nanocatalyst using the sol-gel method. This enhances the interaction strength between the support and the active component, overcoming the shortcomings of existing electrocatalysts in terms of activity and stability. It also improves the adsorption behavior of carbon monoxide molecules, thereby increasing the selectivity and stability of the electrocatalytic reduction of carbon monoxide to acetic acid. This catalyst can achieve [results] at 100 cm⁻¹. 2 The membrane electrode assembly operated continuously and stably for 2400 hours with a total current of 15A, while maintaining good acetic acid Faraday efficiency.

[0040] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a copper oxide / scandium oxide composite nanocatalyst, characterized in that, Includes the following steps: S1. Mix the copper source and scandium source with citric acid solution to obtain a clear solution; S2. Stir and heat the clarified solution to obtain a mixed sol; S3. The mixed sol is gradually evaporated under heating conditions to obtain a gel precursor; S4. The gel precursor is calcined in air to obtain a copper oxide / scandium oxide composite nano-electrocatalyst.

2. The preparation method of the copper oxide / scandium oxide composite nano-electrocatalyst according to claim 1, characterized in that, In step S1, the molar ratio of the copper source to the scandium source is 1:(10-100).

3. The preparation method of the copper oxide / scandium oxide composite nano-electrocatalyst according to claim 1, characterized in that, The solvent for the citric acid solution is anhydrous ethanol, and the concentration of citric acid is 0.02-0.06 g / mL; The total mass of the copper source and scandium source to the citric acid solution has a mass-to-volume ratio of 0.022 g to 0.024 g: 1 mL.

4. The preparation method of the copper oxide / scandium oxide composite nano-electrocatalyst according to claim 1, characterized in that, In step S2, the heating is carried out at 100-150°C for 1-5 hours.

5. The preparation method of the copper oxide / scandium oxide composite nano-electrocatalyst according to claim 1, characterized in that, In step S3, the heating is carried out at 180-220°C for 1-5 hours.

6. The method for preparing the copper oxide / scandium oxide composite nano-electrocatalyst according to claim 1, characterized in that, In step S4, the calcination temperature is 750-850℃, the time is 6-12 h, and the heating rate is 5-10℃ / min.

7. A copper oxide / scandium oxide composite nano-electrocatalyst, characterized in that, It is obtained by the preparation method according to any one of claims 1-6.

8. The application of the copper oxide / scandium oxide composite nanocatalyst according to claim 7 in the electrocatalytic reduction reaction of carbon monoxide.

9. The application according to claim 8, characterized in that, include: The copper oxide / scandium oxide composite nano-electrocatalyst was prepared into a dispersion, then sprayed onto a gas diffusion electrode to assemble a three-electrode gas diffusion electrolytic cell or a membrane electrode electrolytic cell, and carbon monoxide was introduced to carry out the electrocatalytic reaction.

10. The application according to claim 9, characterized in that, The amount of copper oxide / scandium oxide composite nanocatalyst supported on the gas diffusion electrode is 0.5-2 mg / cm³. 2 The dispersion also contains Nafion solution; The products of the electrocatalytic reaction include one or more of acetic acid, ethanol, and ethylene, and the mass content of acetic acid is greater than 60%.

Images