阅读说明：本技术 一种铋铜双金属催化剂的制备方法及应用 (Preparation method and application of bismuth-copper bimetallic catalyst ) 是由 张霞 毛艳丽 焦学然 康海彦 宋忠贤 延旭 张传宗 王明辉 闫晓乐 谷得明 于 2021-10-25 设计创作，主要内容包括：本发明公开一种铋铜双金属催化剂的制备方法,属于二氧化碳电化学还原催化剂制备及应用技术领域,铋盐和铜盐通过溶液化学还原方法合成铋铜双金属催化剂。本发明为BiCu双金属催化剂,由溶液化学还原方法合成,通过有效调控催化剂合成条件,获得BiCu双金属催化剂,可以极大提高二氧化碳还原的选择性,降低CO-(2)还原的过电势,提高能量效率,同时有效地抑制二氧化碳还原过程中的竞争性析氢副反应,提高了甲酸盐的选择性,有效提高了CO-(2)的利用率和转化率。(The invention discloses a preparation method of a bismuth-copper bimetallic catalyst, belonging to the technical field of preparation and application of carbon dioxide electrochemical reduction catalysts. The BiCu bimetallic catalyst is synthesized by a solution chemical reduction method, and is obtained by effectively regulating and controlling the synthesis conditions of the catalyst, so that the selectivity of carbon dioxide reduction can be greatly improved, and CO is reduced 2 Reduced perPotential, energy efficiency is improved, competitive hydrogen evolution side reaction in the reduction process of carbon dioxide is effectively inhibited, selectivity of formate is improved, and CO is effectively improved 2 Utilization and conversion.)

1. The preparation method of the bismuth-copper bimetallic catalyst is characterized in that bismuth salt and copper salt are synthesized into the bismuth-copper bimetallic catalyst by a solution chemical reduction method.

2. The method of preparing a bismuth copper bimetallic catalyst of claim 1, comprising the steps of: 1) dissolving bismuth salt and copper salt in an organic solvent, adding polyvinylpyrrolidone, and mixing to obtain a catalyst precursor solution, wherein the ratio of the mass of polyvinylpyrrolidone to the sum of the mass of metal ion substances in bismuth salt and copper salt is (1-5): 1-10);

2) dissolving a sodium borohydride solution in an organic solvent to obtain a reduction solution;

3) and (3) adding the reduction solution obtained in the step 2) into the catalyst precursor solution obtained in the step 1) for chemical reaction, then carrying out centrifugal separation on the obtained suspension, washing, centrifuging and drying in vacuum to obtain the bismuth-copper bimetallic catalyst, wherein the ratio of the amount of the sodium borohydride in the sodium borohydride solution to the sum of the amounts of the bismuth salt and the metal ion substances in the copper salt is (3-8): 1.

3. The method of claim 2, wherein in step 1), the molar ratio of bismuth salt to copper salt is (1-3) to (0-1).

4. The method for preparing the bismuth-copper bimetallic catalyst of claim 3, wherein in steps 1) and 2), the organic solvent is N, N-dimethylformamide; the bismuth salt is bismuth nitrate pentahydrate, and the copper salt is copper nitrate trihydrate.

5. The method for preparing the bismuth-copper bimetallic catalyst of claim 4, wherein in the step 3), the chemical reaction is carried out under the control of the conditions that the reaction temperature is 0-25 ℃ and the reaction time is 5-120 min.

6. The method for preparing the bismuth-copper bimetallic catalyst of claim 5, wherein in the step 3), the obtained solid is washed by acetone, absolute ethyl alcohol and deionized water in sequence; the concentration of the sodium borohydride solution was 1M.

7. The preparation method of the bismuth-copper bimetallic catalyst of claim 6, wherein in the step 3), the drying is carried out under vacuum at 50-70 ℃ for 6-8 h.

8. The application of the bismuth-copper bimetallic catalyst prepared by the preparation method of any one of claims 1 to 7 is characterized in that the bismuth-copper bimetallic catalyst is applied to carbon dioxide electrochemical reduction.

9. The application of the bismuth-copper bimetallic catalyst as claimed in claim 8, wherein the bismuth-copper bimetallic catalyst is loaded on a working electrode adopted in the electrochemical reduction of carbon dioxide, and the preparation method comprises the following steps: 1) dispersing a bismuth-copper bimetallic catalyst into isopropanol to obtain catalyst slurry, adding a Nafion solution, and mixing to obtain a mixed solution;

2) and (3) coating the mixed solution obtained in the step 1) on a working electrode body, and drying.

10. The use of a bismuth copper bimetallic catalyst as in claim 9 wherein the working electrode body is carbon paper.

Technical Field

The invention belongs to the technical field of preparation and application of a carbon dioxide electrochemical reduction catalyst.

Background

Since industrialization, carbon dioxide (CO) has been consumed due to fossil energy consumption₂) The emission amount is continuously increased, so that various environmental problems such as global temperature rise, glacier thawing, sea level rise and the like are caused, and the environment which human beings rely on to live faces unprecedented threats and challenges. Thus, CO reduction₂Emission, the search for and development of green energy technology, and the realization of "carbon neutralization" have become a major global concern worldwide.

CO₂The environmental problems caused are outstanding and typical, but CO₂Rather than "waste", it is an abundant, inexpensive, and potentially useful C1 feedstock that can be converted to carbon-based fuels or chemicals by chemical methods, photocatalysis, electrocatalysis, and like techniques [ Dalton trans, 39, 3347-3357 (2010)]. However, CO₂The gas is a gas with very stable chemical properties, the molecules are in a linear and centrosymmetric structure (O = C = O), and the C = O double bond can be opened only under the special environments of high temperature, high pressure and the like and under the condition of catalyst activation by inputting energy. The electrochemical reduction technology utilizes electric energy generated by renewable energy sources such as solar energy, wind energy and the like to drive reduction reaction to convert CO into CO₂ Directly converted into high value-added chemicals and low-carbon fuels (such as formic acid, carbon monoxide, methanol and other hydrocarbons), and the reaction process is controllable (by changing the electrolytic strip)Parts, such as electrode and electrolyte, selectively control the generation of products), compact electrochemical system structure and easy scale-up [ chem. Soc. Rev., 43 (2014) 631-]. Thus, the electrochemical reduction technique is to carry out CO₂One of the effective means for energy conversion and utilization realizes CO₂The converted 'carbon neutral' cycle reduces the emission of fossil energy carbon, realizes the storage of intermittent electric energy in high-energy density substances, and has an optimistic application prospect [ Joule, 2(2018)825-]。

Bismuth, an environmentally friendly and economical metal, is an ideal catalyst choice [ J. Am. chem. Soc., 136 (2014) 8361-]. Copper is another potential catalytic metal with unique properties for the production of carbon monoxide, formic acid and various hydrocarbons such as methane, ethanol and ethylene [ Advanced materials, 32 (2020) e1908398, Chinese J Chem, 37 (2019) 497-500-]. However, at present, the Cu catalyst still has a plurality of challenges, such as low Energy efficiency, poor selectivity of target products and the like [ Nano Energy 53 (2018) 27-36]. Synthesizing binary or multicomponent catalyst, regulating the geometric structure and electronic structure of local environment, and raising the activity, selectivity and stability of catalyst by means of synergistic effect of several components₂Efficient pathways for electrocatalytic performance [ J. Am. chem. Soc. 139 (2017) 4290-4293, adv. Energy mater.8 (2018) ] 1802427]。

Disclosure of Invention

The invention aims to provide a preparation method of a bismuth-copper bimetallic catalyst, and simultaneously provides an application of the bismuth-copper bimetallic catalyst, which is another aim of the invention.

Based on the purpose, the invention adopts the following technical scheme:

a bismuth-copper bimetallic catalyst is prepared from bismuth salt and copper salt through solution chemical reduction.

A preparation method of a bismuth-copper bimetallic catalyst comprises the following steps: 1) dissolving bismuth salt and copper salt in an organic solvent, adding polyvinylpyrrolidone, and mixing to obtain a catalyst precursor solution, wherein the ratio of the mass of polyvinylpyrrolidone to the sum of the mass of metal ion substances in bismuth salt and copper salt is (1-5): 1-10);

2) dissolving a sodium borohydride solution in an organic solvent to obtain a reduction solution;

3) and (3) adding the reduction solution obtained in the step 2) into the catalyst precursor solution obtained in the step 1) for chemical reaction, then carrying out centrifugal separation on the obtained suspension, and then washing, centrifuging and vacuum-drying the obtained solid to obtain the bismuth-copper bimetallic catalyst, wherein the ratio of the amount of the sodium borohydride in the sodium borohydride solution to the sum of the amounts of the bismuth salt and the metal ion substances in the copper salt is (3-8): 1.

In the step 1), the molar ratio of the bismuth salt to the copper salt is (1-3) to (0-1).

In the steps 1) and 2), the organic solvent is N, N-dimethylformamide; the bismuth salt is bismuth nitrate pentahydrate, and the copper salt is copper nitrate trihydrate.

In the step 3), the chemical reaction is carried out under the control condition that the reaction temperature is 0-25 ℃ and the reaction time is 5-120 min.

In the step 3), the solid is sequentially washed for 2 times by acetone, absolute ethyl alcohol and deionized water respectively; the concentration of the sodium borohydride solution was 1M.

In the step 3), vacuum drying is carried out for 6-8 h at the temperature of 50-70 ℃.

The bismuth-copper bimetallic catalyst is applied to electrochemical reduction of carbon dioxide.

The application of the bismuth-copper bimetallic catalyst and the preparation method of the bismuth-copper bimetallic catalyst loaded on the working electrode in the electrochemical reduction of carbon dioxide comprise the following steps: 1) dispersing a bismuth-copper bimetallic catalyst into isopropanol to obtain catalyst slurry, adding a Nafion solution, and mixing to obtain a mixed solution;

2) and (3) coating the mixed solution obtained in the step 1) on a working electrode body, and drying.

The bismuth-copper bimetallic catalyst is applied, and the working electrode body is carbon paper.

Compared with the prior art, the invention has the following beneficial effects:

the invention is a BiCu bimetallic catalyst, which is synthesized by a solution chemical reduction method, obtains BiCu bimetallic catalysis by effectively regulating and controlling the synthesis conditions of the catalyst, reduces the overpotential, improves the energy efficiency,

compared with the prior art, the invention has the beneficial effects that:

(1) the BiCu bimetallic catalyst is synthesized by a solution chemical reduction method, and is obtained by effectively regulating and controlling the synthesis conditions of the catalyst, so that the selectivity of carbon dioxide reduction can be greatly improved, and CO is reduced₂The overpotential of the reduction improves the energy efficiency, simultaneously effectively inhibits the competitive hydrogen evolution side reaction in the carbon dioxide reduction process, improves the selectivity of formate, and effectively improves CO₂Utilization and conversion of;

(2) the invention is a BiCu bimetallic nanoparticle catalyst, the particle size of the catalyst is 5-10 nm, the exposed area of an active site is increased, and the yield of a conversion product is improved;

(3) the preparation method disclosed by the invention is simple, convenient to operate, mild in reaction conditions, high in yield, strong in controllability, and easy for large-scale production, and has good application prospects in the fields of carbon dioxide electrochemical reduction, carbon dioxide photoelectric reduction, carbon dioxide photocatalytic reduction and the like.

Drawings

In order to more clearly illustrate the technical solution of the present invention, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

FIG. 1 shows Bi in example 1₂Cu₁TEM of transmission electron microscopy of bimetallic catalysts;

FIG. 2 shows Bi in example 1₂Cu₁TEM (transmission electron microscope) image of high magnification of the bimetallic catalyst;

FIG. 3 shows Bi in examples 1 to 3_xCu_yBimetallic catalyst in CO₂Saturated 0.5M KHCO₃Linear scan graph of (1);

FIG. 4 is a drawing showingIn examples 4 to 5, Bi_xCu_yBimetallic catalyst in CO₂Saturated 0.5M KHCO₃Linear scan graph of (1);

FIG. 5 shows the catalyst in CO in examples 1 and 4₂Saturated 0.5M KHCO₃in-1.45V electrolysis for 1 hour, the faradaic efficiency chart of formate is generated.

Detailed Description

The technical solution of the present invention will be described in detail below in order to make the objects, technical solutions and advantages of the present invention clearer, but the following embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the examples given herein without any inventive step, are within the scope of the present invention.

A bismuth-copper bimetallic catalyst is prepared from bismuth salt and copper salt through solution chemical reduction.

Example 1

A preparation method of a bismuth-copper bimetallic catalyst comprises the following steps: 1) dissolving 0.333mmol of bismuth nitrate pentahydrate and 0.167mmol of copper nitrate trihydrate in 50 ml of N, N-dimethylformamide, sealing, magnetically stirring for 15min, adding 0.056 g (0.5 mmol) of polyvinylpyrrolidone (K30), and magnetically stirring for 15min to obtain a catalyst precursor solution;

2) 2.5 ml of a 1M sodium borohydride solution (sodium borohydride: 2.5 mmol) is dissolved in 10 ml of N, N-dimethylformamide and is stirred evenly to obtain a reducing solution;

3) dropwise adding the reducing solution obtained in the step 2) into the catalyst precursor solution obtained in the step 1), carrying out chemical reaction for 2 hours at 25 ℃, carrying out centrifugal separation on the obtained suspension, sequentially washing the solids for 2 times by using acetone, absolute ethyl alcohol and deionized water respectively, carrying out centrifugal separation, placing the solids in a vacuum drying oven at 60 ℃, and carrying out vacuum drying for 7 hours to obtain the bismuth-copper bimetallic catalyst, wherein the particle size of the bismuth-copper bimetallic catalyst is 5-10 nm, and the TEM image of the prepared catalyst is shown in FIG. 1 and the TEM image of a high-magnification TEM image is shown in FIG. 2.

Example 2

A preparation method of a bismuth-copper bimetallic catalyst comprises the following steps: 1) dissolving 0.375mmol bismuth nitrate pentahydrate and 0.125mmol copper nitrate trihydrate in 50 ml N, N-dimethylformamide, sealing, magnetically stirring for 15min, adding 0.056 g (0.5 mmol) of polyvinylpyrrolidone (K30), and magnetically stirring for 15min to obtain a catalyst precursor solution;

2) 2.5 ml of a 1M sodium borohydride solution (sodium borohydride: 2.5 mmol) is dissolved in 10 ml of N, N-dimethylformamide and is stirred evenly to obtain a reducing solution;

3) and (3) dropwise adding the reduction solution obtained in the step 2) into the catalyst precursor solution obtained in the step 1), carrying out chemical reaction for 2 hours at 25 ℃, then carrying out centrifugal separation on the obtained suspension, sequentially washing the solids for 2 times by using acetone, absolute ethyl alcohol and deionized water respectively, carrying out centrifugal separation, placing the solids in a vacuum drying oven at 60 ℃, and carrying out vacuum drying for 7 hours to obtain the bismuth-copper bimetallic catalyst.

Example 3

A preparation method of a bismuth-copper bimetallic catalyst comprises the following steps: 1) dissolving 0.25mmol of bismuth nitrate pentahydrate and 0.25mmol of copper nitrate trihydrate in 50 ml of N, N-dimethylformamide, sealing, magnetically stirring for 15min, adding 0.056 g (0.5 mmol) of polyvinylpyrrolidone (K30), and magnetically stirring for 15min to obtain a catalyst precursor solution;

2) 2.5 ml of a 1M sodium borohydride solution (sodium borohydride: 2.5 mmol) is dissolved in 10 ml of N, N-dimethylformamide and is stirred evenly to obtain a reducing solution;

3) and (3) dropwise adding the reduction solution obtained in the step 2) into the catalyst precursor solution obtained in the step 1), carrying out chemical reaction for 2 hours at 25 ℃, then carrying out centrifugal separation on the obtained suspension, sequentially washing the solids for 2 times by using acetone, absolute ethyl alcohol and deionized water respectively, carrying out centrifugal separation, placing the solids in a vacuum drying oven at 60 ℃, and carrying out vacuum drying for 7 hours to obtain the bismuth-copper bimetallic catalyst.

Example 4

A preparation method of a bismuth-copper bimetallic catalyst comprises the following steps: 1) dissolving 0.5mmol of bismuth nitrate pentahydrate in 50 ml of N, N-dimethylformamide, sealing, magnetically stirring for 15min, adding 0.056 g (0.5 mmol) of polyvinylpyrrolidone (K30), and magnetically stirring for 15min to obtain a catalyst precursor solution;

2) 2.5 ml of a 1M sodium borohydride solution (sodium borohydride: 2.5 mmol) is dissolved in 10 ml of N, N-dimethylformamide and is stirred evenly to obtain a reducing solution;

3) and (3) dropwise adding the reduction solution obtained in the step 2) into the catalyst precursor solution obtained in the step 1), carrying out chemical reaction for 2 hours at 25 ℃, carrying out centrifugal separation on the obtained suspension, sequentially washing the solids for 2 times by using acetone, absolute ethyl alcohol and deionized water respectively, carrying out centrifugal separation, placing the solids in a vacuum drying oven at 60 ℃, and carrying out vacuum drying for 7 hours to obtain the bismuth metal catalyst.

Example 5

A preparation method of a bismuth-copper bimetallic catalyst comprises the following steps: 1) dissolving 0.333mmol of bismuth nitrate pentahydrate and 0.167mmol of copper nitrate trihydrate in 50 ml of N, N-dimethylformamide, sealing, magnetically stirring for 15min, adding 0.028 g (0.25 mmol) of polyvinylpyrrolidone (K30), and magnetically stirring for 15min to obtain a catalyst precursor solution;

2) 2.5 ml of a 1M sodium borohydride solution (sodium borohydride: 2.5 mmol) is dissolved in 10 ml of N, N-dimethylformamide and is stirred evenly to obtain a reducing solution;

3) and (3) dropwise adding the reduction solution obtained in the step 2) into the catalyst precursor solution obtained in the step 1), carrying out chemical reaction for 2 hours at 25 ℃, then carrying out centrifugal separation on the obtained suspension, sequentially washing the solids for 2 times by using acetone, absolute ethyl alcohol and deionized water respectively, carrying out centrifugal separation, placing the solids in a vacuum drying oven at 60 ℃, and carrying out vacuum drying for 7 hours to obtain the bismuth-copper bimetallic catalyst.

Example 6 application Performance testing

The bismuth-copper bimetallic catalysts prepared in the embodiments 1 to 5 are applied to carbon dioxide electrochemical reduction, and the working electrode adopted in the carbon dioxide electrochemical reduction is loaded with the bismuth-copper bimetallic catalyst, and the preparation method comprises the following steps: 1) dispersing 7.5 mg of bismuth-copper bimetallic catalyst into 0.5 ml of isopropanol to obtain catalyst slurry, then adding 50 mg of 5% Nafion solution, and uniformly dispersing by ultrasonic to obtain a mixed solution;

2) will be provided withStep 1) the mixed solution was applied to a working electrode body (1X 2 cm)²Carbon paper), placing the electrode on a vacuum drying oven, drying for 1h at the temperature of 60 ℃ to obtain a working electrode loaded with bismuth-copper bimetallic catalyst, wherein the catalyst loading capacity is 3 mg cm^-2The saturated calomel electrode is a reference electrode, and the platinum sheet is an auxiliary electrode.

The linear scan curve (LSV) of the catalyst was determined with an electrochemical workstation. At 0.5M KHCO₃The LSV curve of each example catalyst was determined by passing nitrogen through the solution for 30 min and then carbon dioxide through the solution for 30 min. The results of the experiments of examples 1 to 3 are shown in FIG. 3, and the results of the experiments of examples 4 to 5 are shown in FIG. 4.

Then, electrolysis was carried out at-1.45V for 1 hour, and the Faraday efficiency for formate production was measured. The test results of examples 1 and 4 are shown in fig. 5.

Wherein, example 1 is Bi in FIG. 3₂Cu₁Example 2 shows Bi in FIG. 3₃Cu₁Example 3 shows Bi in FIG. 3₁Cu₁Example 4 is Bi in FIG. 4, and example 5 is Bi in FIG. 4₂Cu₁ ^/。

As can be seen from FIG. 3, Bi of example 1 was observed at-1.7V₂Cu₁The current density of (A) was-15.1 mA cm^-2Bi of example 2₃Cu₁The current density of (A) was-13.8 mA cm^-2Bi of example 3₁Cu₁The current density of (A) was-10.8 mA cm^-2Example 2 Bi₃Cu₁And 3 Bi₁Cu₁Current density lower than Bi in example 1₂Cu₁Current density of (1), and Bi of example 1₂Cu₁Is higher than that of example 2 Bi₃Cu₁And 3 Bi₁Cu₁Correction, Bi of example 1 will be explained₂Cu₁To CO₂The catalytic reduction performance of (2) is superior to that of examples 2 and 3.

As can be seen from FIG. 4, the current density of Bi of example 4 was 14.8 mA cm at-1.7V^-2Example 5Bi₂Cu₁ ^/Has a current density of 11.2 mA cm^-2Examples 4 and 5Current density lower than Bi in example 1₂Cu₁Current density of (1), and Bi of example 1₂Cu₁The peak potential of the alloy is higher than that of the Bi of example 4 and that of the Bi of example 5₂Cu₁ ^/And (6) correcting.

As can be seen from FIG. 5, at-1.45V, example 1 Bi₂Cu₁The Faraday efficiency for formic acid is higher than that of example 4 Bi, which shows that Bi₂Cu₁To CO₂The catalytic reduction performance of the catalyst is better than that of Bi.

The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.