Preparation method and application of copper borate electrocatalyst

Abstract

The invention relates to the technical field of electrocatalysts, in particular to a preparation method and application of a cupric borate electrocatalyst.The preparation method comprises the steps that a sodium tetraborate solution is dissolved in water to form a single uniform solution, and a solution A is prepared; copper salt is weighed and dissolved in deionized water to form a single uniform solution, and a solution B is prepared; slowly dropwise adding the solution B into the solution A to form a blue solution C; the solution C is heated and subjected to heat preservation, a reactant is obtained after the reaction is finished and cooled, the reactant is washed and dried, and the copper borate electrocatalyst is obtained; reducing CO2 with different concentrations by using a copper borate electrocatalyst; according to the method, different copper sources are adopted to react with sodium tetraborate, the synthesis temperature and time of the reaction are controlled to obtain copper borate, and borate promotes adsorption of reaction intermediates by adjusting transfer of electrons, so that the capability of electrocatalyzing reduction of CO2 with different concentrations is improved.

Description

Technical Field

[0001] The invention relates to the technical field of electrocatalysts, and in particular to a preparation method and application of a copper borate electrocatalyst. Background Art

[0002] Electrocatalytic CO 2 Reduction is a catalytic process driven by renewable energy. It has mild reaction conditions, controllable catalytic process, and its products can be used as fuel and chemical raw materials, and it is possible to put it into practical application on a large scale. 2 Expensive gas process, low concentration CO 2 Direct conversion is an important method.

[0003] Among various electrocatalysts, copper-based catalysts are a promising candidate for obtaining C 2 The electrocatalyst of the product is in the electrocatalytic CO 2 Reduction has been extensively studied.

[0004] However, the application of traditional copper-based catalysts is limited by their low current density, low product selectivity and low activity. 2 Practical applications in the field of reduction. Summary of the invention

[0005] The purpose of the present invention is to provide a preparation method and application of copper borate electrocatalyst, which solves the problem that the traditional copper-based catalyst has low current density, low product selectivity and low activity in application, which limits the application of copper-based catalyst in electrocatalytic CO 2 Problems of practical application in the field of reduction.

[0006] To achieve the above object, the present invention provides a copper borate nanosheet structure catalyst, wherein the length of the nanosheet is 100 to 300 nm and the width is 40 to 50 nm.

[0007] The present invention also provides a method for preparing a copper borate electrocatalyst and application thereof, comprising the following steps:

[0008] Solution A is prepared by dissolving sodium tetraborate solution in water to form a single homogeneous solution;

[0009] Weigh copper salt and dissolve it in deionized water to form a single uniform solution to prepare solution B;

[0010] Slowly adding the solution B to the solution A to form a blue solution C;

[0011] The solution C is heated and kept warm, and after the reaction is completed, it is cooled to obtain a reactant, and the reactant is washed and dried to obtain a copper borate electrocatalyst;

[0012] The copper borate electrocatalyst was used to reduce CO at different concentrations. 2 .

[0013] Wherein, in “dissolving the sodium tetraborate solution in water to form a single uniform solution to obtain solution A”, the method further comprises:

[0014] The sodium tetraborate solution has a sodium tetraborate concentration of 1 to 10 g / L.

[0015] Wherein, in “weighing copper salt and dissolving it in deionized water to form a single uniform solution to prepare solution B”, the method further comprises:

[0016] The copper salt is CuSO 4 , CuCl 2 、Cu(NO 3 ) 2 、Cu(CH 3 COO 2 One of the above, wherein the concentration of the copper salt is 10 to 500 g / L.

[0017] Wherein, in “slowly dropping the solution B into the solution A to form a blue solution C”, the method further comprises:

[0018] The dropping speed is controlled at 1-3 mL / min, the heating temperature is controlled at 25-200° C., and the reaction time is controlled at 1-10 h.

[0019] Among them, in "Using the copper borate electrocatalyst to reduce CO at different concentrations 2 ”, the method further comprises:

[0020] The copper borate electrocatalyst is dispersed in an aqueous solution containing isopropanol, and a perfluorosulfonic acid resin solution is added and uniformly mixed by ultrasonication to obtain a liquid A;

[0021] Applying the liquid A on a hydrophobic carbon paper and drying it in vacuum;

[0022] The vacuum-dried carbon paper was used as the working electrode with a loading of 0.5-1.5 mg / cm 2 , using a flow cell electrocatalytic CO 2 reduction.

[0023] Among them, in "using vacuum dried carbon paper as the working electrode, the loading amount is 0.5-1.5 mg / cm 2 , using a flow cell electrocatalytic CO 2 In "restore", the method further comprises:

[0024] The diluting gas is one of N2 and Ar.

[0025] Among them, in "using vacuum dried carbon paper as the working electrode, the loading amount is 0.5-1.5 mg / cm 2 , using a flow cell electrocatalytic CO 2 In "restore", the method further comprises:

[0026] As diluent gas N 2 and Ar and CO 2 The dilution concentration is 5% to 100% CO 2 .

[0027] The copper borate electrocatalyst prepared by the present invention is used to reduce CO at different concentrations 2 .

[0028] Specifically: copper borate electrocatalyst Cu(BO 2 ) 2 The working electrode was drop-coated on hydrophobic carbon paper, the solid Ag / AgCl (3M) electrode was used as the reference electrode, the Pt sheet was used as the counter electrode, 1M KOH was used as the electrolyte, the cathode and the anode were separated by an ion exchange membrane, and the flow-cell was passed through a three-electrode system. The flowmeter was used to control the N 2 and CO 2 The flow rate is thus reduced to dilute CO 2 The role of electrocatalysis of different concentrations of CO 2 Reduced to multi-carbon products.

[0029] The beneficial effects of the present invention are:

[0030] 1. The present invention uses a simple oil bath method to heat the reaction solution and controls the reaction temperature to prepare Cu(BO 2 ) 2 The reaction conditions are mild, the raw materials are readily available and low in cost, and the preparation process is simple and environmentally friendly.

[0031] 2. In the material of the present invention, inorganic non-metallic ions (BO 2- ) modification of copper ions is beneficial to change the valence band state density of the metal, thereby making the copper ions 2 The reduction process has a strong adsorption capacity for the *CO intermediate, exposing more effective active sites, which is conducive to the occurrence of CC coupling reaction, thereby enhancing the adsorption of C 2 Product selectivity.

[0032] 3. The material of the present invention is effective in electrocatalysis of low concentration CO 2 The reduction process showed good C 2 Selectivity, to further realize industrial electrocatalytic CO 2 It provides an effective solution to the economic and environmental problems caused by restoration. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below.

[0034] Figure 1 The Cu(BO) prepared in Example 1 at different reaction temperatures 2 ) 2 XRD spectra of the materials.

[0035] Figure 2 This is a TEM image of the material prepared in Example 1 at a reaction temperature of 65°C.

[0036] Figure 3 The Cu(BO) prepared in Example 1 at a reaction temperature of 65°C 2 ) 2 In pure CO 2 Electrocatalytic reduction performance under 3.0 conditions.

[0037] Figure 4 The Cu(BO) prepared in Example 1 at a reaction temperature of 65°C 2 ) 2 In different CO 2 CO concentration 2 Reduction product C 2 Product performance comparison chart.

[0038] Figure 5 The Cu(BO) prepared in Example 1 at a reaction temperature of 65°C 2 ) 2 In different CO 2 Comparison of current density under concentration conditions.

[0039] Figure 6 The present invention is a flow chart of the method for preparing the copper borate electrocatalyst.

[0040] Figure 7 The copper borate electrocatalyst of the present invention reduces CO at different concentrations 2 Flowchart of the method. DETAILED DESCRIPTION

[0041] Embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, but should not be construed as limiting the present invention.

[0042] A method for preparing a copper borate electrocatalyst comprises the following steps:

[0043] S101: dissolving a sodium tetraborate solution in water to form a single uniform solution to prepare a solution A;

[0044] S102: Weigh copper salt and dissolve it in deionized water to form a single uniform solution to prepare solution B;

[0045] S103: slowly adding the solution B dropwise into the solution A to form a blue solution C;

[0046] S104: heating the solution C and keeping it warm, cooling it after the reaction is completed to obtain a reactant, washing and drying the reactant to obtain a copper borate electrocatalyst;

[0047] S105: Using the copper borate electrocatalyst to reduce CO at different concentrations 2 .

[0048] First embodiment:

[0049] Weigh 2.0 g of sodium tetraborate decahydrate and dissolve it in 250 mL of deionized water to form solution A, and stir to dissolve. At room temperature (25°C), dissolve 5.0 g of copper sulfate pentahydrate in 10 mL of deionized water and dissolve it by ultrasonic to form solution B. Slowly add copper sulfate B solution dropwise to sodium tetraborate solution A and stir to form solution C. The color of solution C changes to blue and solid precipitates. Heat solution C to 65°C and maintain for 7 hours, wash and dry to obtain a blue-green solid powder (Cu(BO 2 ) 2 ).

[0050] Second embodiment:

[0051] Weigh 2.0 g of sodium tetraborate decahydrate and dissolve it in 250 mL of deionized water to form solution A, and stir to dissolve. At room temperature, dissolve 3.2 g of copper nitrate trihydrate in 10 mL of deionized water and ultrasonically dissolve to form solution B. Slowly add copper nitrate solution B dropwise to sodium borate solution A and stir to form solution C. Solution C turns blue with solid precipitation. Heat to 100°C and maintain for 5 hours, wash and dry to obtain a blue-green solid powder.

[0052] Third embodiment:

[0053] Weigh 1.5 g of sodium tetraborate decahydrate and dissolve it in 200 mL of deionized water to form solution A. Dissolve 2.5 g of cupric chloride dihydrate in 10 mL of deionized water at room temperature to form solution B. Slowly add cupric chloride solution B dropwise to sodium tetraborate solution A and stir to form solution C. Solution C changes color to blue with solid precipitation. Maintain at room temperature (25°C) for 7 hours, wash and dry to obtain a blue-green solid powder.

[0054] Figure 1The X-ray diffraction diagram of the material obtained in Example 1 shows that when the reaction temperature is 25, 65 and 100°C, the diffraction peaks of the sample are similar to those of Cu(BO 2 ) 2 (No.01-472), indicating that Cu(BO 2 ) 2 Material.

[0055] Figure 2 This is the TEM image in Example 1. It can be observed that at 65°C, the material morphology obtained is nanosheet-like with a diameter of 40 to 50 nm.

[0056] Fourth embodiment:

[0057] Application of a copper borate electrocatalyst: 4 mg of Cu(BO 2 ) 2 Disperse in an aqueous solution containing isopropanol, add 10 μL of perfluorosulfonic acid resin solution (Nafion) and mix evenly by ultrasonication. Take 250 μL of liquid (liquid A) and apply it on a 1*1 cm 2 The working electrode was prepared by vacuum drying on hydrophobic carbon paper. 2 During the reduction reaction, the total flow rate of the reaction gas was set to 20 or 30 sccm, and the CO 2 and N 2 The flow rates of 20:0, 15:5, 10:10, and 5:15 were defined as 100% CO 2 , 75% CO 2 , 50% CO 2 and 25% CO 2 But its performance is not limited to this ratio.

[0058] Figures 3 to 5 are respectively Cu(BO 2 ) 2 In different CO 2 Electrocatalytic CO 2 The restored Faraday efficiency diagram shows that the main C 2 Products include ethylene and ethanol, in CO 2 When the concentration is 75%, the highest C 2 The Faraday efficiency can reach 65.00%.

[0059] What is disclosed above is only one or more preferred embodiments of the present application, and cannot be used to limit the scope of rights of the present application. Ordinary technicians in this field can understand that all or part of the processes of implementing the above embodiments and equivalent changes made according to the claims of the present application are still within the scope covered by the present application.

Claims

1. A method for preparing a copper borate electrocatalyst, characterized in that: The following steps are involved: Solution A is prepared by dissolving sodium tetraborate solution in water to form a single homogeneous solution; Weigh copper salt and dissolve it in deionized water to form a single uniform solution to prepare solution B; Slowly adding the solution B to the solution A to form a blue solution C; The solution C is heated and kept warm, and after the reaction is completed, it is cooled to obtain a reactant, and the reactant is washed and dried to obtain a copper borate electrocatalyst; The copper borate electrocatalyst was used to reduce CO2 at different concentrations.

2. The method for preparing the copper borate electrocatalyst according to claim 1, characterized in that: In "dissolving sodium tetraborate solution in water to form a single uniform solution to obtain solution A", the method further comprises: The sodium tetraborate solution has a sodium tetraborate concentration of 1 to 10 g / L.

3. The method for preparing the copper borate electrocatalyst according to claim 2, characterized in that: In "weighing copper salt and dissolving it in deionized water to form a single uniform solution to prepare solution B", the method further includes: The copper salt is one of CuSO4, CuCl2, Cu(NO3)2, and Cu(CH3COO)2, wherein the concentration of the copper salt is 10 to 500 g / L.

4. The method for preparing the copper borate electrocatalyst according to claim 3, characterized in that: In "slowly dropping the solution B into the solution A to form a blue solution C", the method further comprises: The dropping speed is controlled at 1-3 mL / min.

5. The method for preparing the copper borate electrocatalyst according to claim 4, characterized in that: In "heating and keeping the solution C warm, cooling after the reaction is completed to obtain a reactant, washing and drying the reactant to obtain a copper borate electrocatalyst", the method further includes: The heating temperature is controlled at 25-200°C and the reaction time is 1-10 hours.

6. The method for preparing the copper borate electrocatalyst according to claim 5, characterized in that: In "Reducing CO2 of different concentrations using the copper borate electrocatalyst", the method further includes: The copper borate electrocatalyst is dispersed in an aqueous solution containing isopropanol, and a perfluorosulfonic acid resin solution is added and uniformly mixed by ultrasonication to obtain a liquid A; Applying the liquid A on a hydrophobic carbon paper and drying it in vacuum; The vacuum-dried carbon paper was used as the working electrode with a loading of 0.5-1.5 mg / cm 2 , using a flow-type reaction cell for electrocatalytic CO2 reduction.

7. The method for preparing the copper borate electrocatalyst according to claim 6, characterized in that: The vacuum-dried carbon paper was used as the working electrode, and the loading amount was 0.5-1.5 mg / cm 2 , wherein the method further comprises: The diluting gas is one of N2 and Ar.

8. The method for preparing the copper borate electrocatalyst according to claim 7, characterized in that: The vacuum-dried carbon paper was used as the working electrode, and the loading amount was 0.5-1.5 mg / cm 2 , wherein the method further comprises: The dilution concentration of N2 and Ar with CO2 as diluent gases is 5% to 100% CO2.

9. The copper borate electrocatalyst prepared by the preparation method according to any one of claims 1 to 8, characterized in that: Applied to reduce CO2 of different concentrations.

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