Copper-zirconium bimetallic oxide nano-composite catalyst as well as preparation and application thereof

Abstract

The invention relates to the technical field of catalysts, in particular to a copper-zirconium bimetallic oxide nano-composite catalyst as well as preparation and application thereof. The preparation method comprises the following steps: dissolving a precursor salt of copper and zirconium hydroxide, uniformly mixing, and adding an ammonia water solution to obtain a copper-zirconium precursor solution; and carrying out post-treatment on the copper-zirconium precursor solution, and then carrying out roasting treatment to obtain the copper-zirconium bimetallic oxide nano composite catalyst. The preparation method of the copper-zirconium bimetallic oxide nano-composite catalyst has the advantages that the process is simple, the reaction condition is mild, the prepared copper-zirconium bimetallic oxide nano-composite catalyst is good in copper dispersity, and the product has the advantages of strong adsorption to * CO, high conductivity and the like; when the prepared copper-zirconium double-metal oxide nano composite catalyst is further used for preparing methane through electrocatalysis CO2 reduction, the catalyst can effectively inhibit hydrogen evolution side reaction, is high in stability and has high selectivity and excellent stability on methane.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of catalysts, in particular to a copper-zirconium bimetallic oxide nanocomposite catalyst and a preparation and application thereof. BACKGROUND

[0002] In today's society, the overconsumption of fossil energy has led to a sharp increase in carbon dioxide emissions, which has triggered a series of serious environmental problems. At the same time, as a non-renewable resource, fossil fuels are gradually running out. In the face of dual challenges of energy and environment, it has become an inevitable trend to convert CO2 into chemicals.

[0003] Among the many products with high added value, methane stands out as a clean and green energy. The carbon, hydrogen and oxygen elements generated in the combustion process can be recycled, and it can also replace traditional petroleum processes, with very high economic value. Therefore, methane is considered as an attractive target product of CO2 conversion. Among various CO2 conversion technologies, electrocatalytic reduction of carbon dioxide has unique advantages. This reaction can convert CO2 into methane and other products with high added value under the driving of renewable clean energy. Moreover, it has the advantages of mild reaction conditions and easy control of reaction process, and therefore has received extensive attention.

[0004] In the field of catalysts for electrocatalytic reduction of CO2 to prepare methane, copper (Cu) -based catalysts can reduce the high activation energy barrier in the reaction process and convert CO2 into active intermediates. Copper (Cu) has weak adsorption ability for hydrogen (H) and moderate adsorption ability for carbon monoxide (CO), and has become the most potential effective catalyst component in the reaction of electrocatalytic reduction of CO2 to generate methane. In particular, CuO has been proven to exhibit excellent catalytic activity in electrocatalytic reduction of CO2. However, there are still some shortcomings in existing copper-based catalysts, such as serious hydrogen evolution reaction, multiple product types and poor stability, which to some extent limit its application and development. Therefore, it is possible to introduce a second phase of metal oxide to improve the selectivity of reduction products by constructing a metal oxide interface.

[0005] Currently in the field of carbon dioxide electro-reduction reaction (CO2RR) catalyst research, single metal catalysts such as copper (Cu), gold (Au), silver (Ag), zinc (Zn), palladium (Pd), lead (Pb) and the like have received more attention. However, these single metal catalysts have certain limitations in practical application, and their product selectivity and Faraday conversion efficiency still have a lot of room for improvement. In contrast, non-single metal catalysts can significantly improve the catalytic activity of CO2 reduction and effectively improve the product selectivity due to their unique structure and performance advantages. For example: patent CN106180747A discloses a palladium-copper binary alloy nanomaterial that can efficiently convert CO2 into formic acid and natural gas, and the combined conversion efficiency of formic acid and methane can be up to 70% or more. However, the preparation process of this catalyst uses palladium noble metal, which is expensive and not suitable for industrial application, and the product has limited single selectivity. Patent CN120041861A discloses a preparation method of a copper-based catalyst for electrocatalytic CO2 reduction to prepare CH4, which uses silica nanospheres as a carrier. The catalyst is composed of an active component and a carrier, and the active component is Cu. However, the preparation process is relatively complicated, and the Faraday efficiency of methane is relatively low.

[0006] Therefore, finding a more suitable method for electrocatalytic CO2 to solve the above problems has become one of the topics of concern by many leading researchers in the academic community. SUMMARY

[0007] In order to solve the above problems, the purpose of the present application is to provide a copper-zirconium bimetallic oxide nanocomposite catalyst and its preparation and application. The preparation method of the copper-zirconium bimetallic oxide nanocomposite catalyst in the present application has the advantages of simple process, mild reaction conditions, good copper dispersion of the prepared copper-zirconium bimetallic oxide nanocomposite catalyst, strong adsorption of products to CO and high conductivity. When the copper-zirconium bimetallic oxide nanocomposite catalyst prepared by the present application is further used for electrocatalytic CO2 reduction to prepare methane, the catalyst can effectively inhibit the hydrogen evolution side reaction, has high stability, and has high selectivity and excellent stability to methane.

[0008] The purpose of the present application can be achieved by the following technical solutions:

[0009] The first purpose of the present application is to provide a preparation method of a copper-zirconium bimetallic oxide nanocomposite catalyst, comprising the following steps:

[0010] (S1) dissolving and mixing copper precursor salt and zirconium hydroxide and adjusting the pH to obtain a copper-zirconium precursor solution;

[0011] (S2) the copper-zirconium precursor solution prepared in step (S1) is post-treated and then subjected to calcination treatment to obtain a copper-zirconium bimetallic oxide nanocomposite catalyst.

[0012] In one embodiment of the present application, in step (S1), the precursor salt of copper is selected from one or more of copper chloride, copper nitrate trihydrate, copper carbonate basic or copper acetate.

[0013] In one embodiment of the present application, in step (S1), the mass ratio of the precursor salt of copper to zirconium hydroxide is 0.01-0.5:1.

[0014] In one embodiment of the present application, in step (S1), during the mixing process, the temperature is room temperature and the time is 0.5-1 h.

[0015] In one embodiment of the present application, in step (S1), the pH of the copper-zirconium precursor solution is adjusted to 9-11 using an aqueous ammonia solution.

[0016] In one embodiment of the present application, in step (S2), the post-treatment is sequentially subjecting the copper-zirconium precursor solution to standing, washing and drying treatment.

[0017] In one embodiment of the present application, during the standing process, the temperature is room temperature and the time is 0.5-1.5 h.

[0018] During the washing process, the copper-zirconium precursor solution is washed with ethanol and deionized water several times, respectively.

[0019] During the drying process, the temperature is 60-80℃ and the time is 10-14 h under vacuum.

[0020] In one embodiment of the present application, in step (S2), during the calcination treatment, the temperature is 200-600℃ and the time is 2-6 h.

[0021] The second object of the present application is to provide a copper-zirconium bimetallic oxide nanocomposite catalyst, which is prepared by the above method.

[0022] The third object of the present application is to provide an application of the copper-zirconium bimetallic oxide nanocomposite catalyst in electrocatalytic CO2 reduction to produce methane.

[0023] The Cu / ZrO2 interface in the copper-zirconium bimetallic oxide nanocomposite catalyst prepared by the method can enhance the adsorption stability of the CO intermediate, thereby promoting the protonation of the CO intermediate, inhibiting C-C coupling, and improving the selectivity of electrocatalytic reduction of CO2 to methane. The method of the application obtains highly dispersed ultra-small copper nanoclusters loaded on nano-zirconia by deposition precipitation, enhances the adsorption stability of the CO intermediate, thereby promoting the protonation of the CO intermediate, inhibiting C-C coupling, improving the selectivity of electrocatalytic reduction of CO2 to methane, and improving the ability of the above-mentioned copper-zirconium bimetallic composite to activate carbon dioxide, thereby realizing high selectivity and high activity of electrocatalytic reduction of carbon dioxide to methane, and providing a new way for efficient conversion of carbon dioxide. At present, copper-based catalysts have been proved to be able to electrocatalytically reduce CO2 to various hydrocarbons, so copper-based catalysts have been widely studied. However, the traditional copper-based catalysts still have problems such as low activity and selectivity for specific products, poor stability and the like. The copper-zirconium bimetallic composite catalyst provided by the application is further used for electrocatalytic reduction of CO2 to methane, realizing 78% selectivity of methane and excellent stability of 12h.

[0024] Compared with the prior art, the application has the following beneficial effects:

[0025] (1) The application provides a preparation method of a copper-zirconium bimetallic oxide nanocomposite catalyst aiming at the problems of serious hydrogen evolution reaction of copper-based catalysts, unsatisfactory current density, poor stability and wide product distribution. The interface of copper and zirconia in the copper-zirconium bimetallic oxide nanocomposite catalyst can enhance the activity of electrocatalytic reduction of CO2 and improve the selectivity to methane. Nano-zirconia usually has small nanometer size and large specific surface area. Small particle size means more active sites exposed on the surface, which is beneficial to the adsorption of reactant molecules and the progress of reaction. The large specific surface area increases the contact area with the reactants and improves the reaction efficiency.

[0026] (2) The copper-zirconium bimetallic oxide nanocomposite catalyst can enhance the ability of zirconium to provide electrons to Cu, make the valence state of Cu and the valence state of O more stable, and improve the stability of the catalyst in alkaline electrolyte by introducing transition metals into the zirconia lattice to form transition metal-doped zirconia and adsorbing the transition metal-doped zirconia on copper oxide to form a heterostructure.

[0027] (3) The application uses nanoscale monoclinic zirconia as a carrier, which has high surface basicity and excellent CO2 adsorption capacity, can increase the coverage of Cu 0 on the surface of the catalyst, and monoclinic zirconia can enhance the adsorption of the CO intermediate, thereby promoting the protonation of the CO intermediate, inhibiting C-C coupling, and improving the selectivity of electrocatalytic reduction of CO2 to methane. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 Total current density and Faraday efficiency (FE) of the copper-zirconium bimetallic oxide nanocomposite catalyst prepared in Example 1 at different potentials;

[0029] Figure 2 Linear sweep voltammetry (LSV) of the copper-zirconium bimetallic oxide nanocomposite catalyst prepared in Example 1;

[0030] Figure 3 Total current density and Faraday efficiency (FE) of the copper-zirconium bimetallic oxide nanocomposite catalyst prepared in Examples 1-5 at a voltage of -1.9 V vs. RHE;

[0031] Figure 4 Total current density and Faraday efficiency (FE) of the catalyst prepared in Example 1, Example 7, and Example 8 at a voltage of -1.9 V vs. RHE;

[0032] Figure 5 Total current density and Faraday efficiency (FE) of the catalyst prepared in Example 1, Comparative Example 1, and Comparative Example 2 at a voltage of -1.9 V vs. RHE. DETAILED DESCRIPTION

[0033] The present application will be described in detail below with reference to the accompanying drawings and specific examples.

[0034] In the following examples, the reagents used are commercially available unless otherwise specified, and the detection means and methods used are conventional detection means and methods in the art.

[0035] Example 1

[0036] This example provides a copper-zirconium bimetallic oxide nanocomposite catalyst, which is prepared by the following method:

[0037] (S1) 0.1 g of Cu(NO3)2·3H2O was dissolved in 10 mL of deionized water, and after stirring until uniform, 1 g of zirconium hydroxide was added, followed by the addition of 3 mL of 0.5 M NH3·3H2O, and the pH was adjusted to 10. The mixture was stirred for 0.5 h to obtain a blue solution: a copper-zirconium precursor solution;

[0038] (S2) The copper-zirconium precursor solution prepared in (S1) was allowed to stand for 1 h, and the product was washed with ethanol and water three times each. After the washing was completed, the product was dried in a vacuum drying oven at 80°C for 12 h, and then calcined at 350°C for 3 h to obtain a copper-zirconium bimetallic oxide nanocomposite catalyst (labeled as "M3").

[0039] The total current density and Faraday efficiency (FE) of the copper-zirconium bimetallic oxide nanocomposite catalyst prepared in this example at different potentials are shown in Figure 1 The linear sweep voltammetry curve (LSV) is shown in Figure 2 The total current density and Faraday efficiency (FE) at a voltage of -1.9 V versus RHE are shown in Figures 3-5

[0040] Example 2

[0041] This example provides a copper-zirconium bimetallic oxide nanocomposite catalyst, which is prepared by the following method:

[0042] (S1) 0.01 g of Cu(NO3)2·3H2O was dissolved in 10 mL of deionized water, and after stirring uniformly, 1 g of zirconium hydroxide was added, 3 mL of 0.5 M NH3·3H2O was added, the pH was adjusted to 10, and stirring was performed for 0.5 h to obtain a blue solution: copper-zirconium precursor solution;

[0043] (S2) The copper-zirconium precursor solution prepared in (S1) was allowed to stand for 1 h, the product was washed with ethanol and water three times respectively, after the end of washing, it was dried in a vacuum drying oven at 80°C for 12 h, and after the end of drying, it was calcined at 350°C for 3 h to obtain a copper-zirconium bimetallic oxide nanocomposite catalyst (labeled as "M1").

[0044] The total current density and Faraday efficiency (FE) of the copper-zirconium bimetallic oxide nanocomposite catalyst prepared in this example at a voltage of -1.9 V versus RHE are shown in Figure 3

[0045] Example 3

[0046] This example provides a copper-zirconium bimetallic oxide nanocomposite catalyst, which is prepared by the following method:

[0047] (S1) 0.05 g of Cu(NO3)2·3H2O was dissolved in 10 mL of deionized water, and after stirring uniformly, 1 g of zirconium hydroxide was added, 3 mL of 0.5 M NH3·3H2O was added, the pH was adjusted to 10, and stirring was performed for 0.5 h to obtain a blue solution: copper-zirconium precursor solution;

[0048] (S2) The copper-zirconium precursor solution prepared in (S1) was allowed to stand for 1 h, the product was washed with ethanol and water three times respectively, after the end of washing, it was dried in a vacuum drying oven at 80°C for 12 h, and after the end of drying, it was calcined at 350°C for 3 h to obtain a copper-zirconium bimetallic oxide nanocomposite catalyst (labeled as "M2").

[0049] ​​The total current density and Faraday efficiency (FE) of the copper-zirconium bimetallic oxide nanocomposite catalyst prepared in this example at a voltage of -1.9 V vs RHE are shown in Table 1. Figure 3

[0050] Example 4

[0051] This example provides a copper-zirconium bimetallic oxide nanocomposite catalyst, which is prepared by the following method:

[0052] (S1) 0.3 g of Cu(NO3)2·3H2O was dissolved in 10 mL of deionized water, and after stirring uniformly, 1 g of zirconium hydroxide was added, 3 mL of 0.5 M NH3·3H2O was added, the pH was adjusted to 10, and stirring was performed for 0.5 h to obtain a blue solution: copper-zirconium precursor solution;

[0053] (S2) The copper-zirconium precursor solution prepared in (S1) was allowed to stand for 1 h, the product was washed with ethanol and water three times, respectively, after the end of washing, it was dried in a vacuum drying oven at 80°C for 12 h, and after the end of drying, it was calcined at 350°C for 3 h to obtain a copper-zirconium bimetallic oxide nanocomposite catalyst (labeled as “M4”).

[0054] The total current density and Faraday efficiency (FE) of the copper-zirconium bimetallic oxide nanocomposite catalyst prepared in this example at a voltage of -1.9 V vs RHE are shown in Table 1. Figure 3

[0055] Example 5

[0056] This example provides a copper-zirconium bimetallic oxide nanocomposite catalyst, which is prepared by the following method:

[0057] (S1) 0.5 g of Cu(NO3)2·3H2O was dissolved in 10 mL of deionized water, and after stirring uniformly, 1 g of zirconium hydroxide was added, 3 mL of 0.5 M NH3·3H2O was added, the pH was adjusted to 10, and stirring was performed for 0.5 h to obtain a blue solution: copper-zirconium precursor solution;

[0058] (S2) The copper-zirconium precursor solution prepared in (S1) was allowed to stand for 1 h, the product was washed with ethanol and water three times, respectively, after the end of washing, it was dried in a vacuum drying oven at 80°C for 12 h, and after the end of drying, it was calcined at 350°C for 3 h to obtain a copper-zirconium bimetallic oxide nanocomposite catalyst (labeled as “M4”).

[0059] The total current density and Faraday efficiency (FE) of the copper-zirconium bimetallic oxide nanocomposite catalyst prepared in this example at a voltage of -1.9 V vs RHE are shown in Table 1. Figure 3 ​​​

[0060] Example 6

[0061] The present example provides a copper-zirconium bimetallic oxide nanocomposite catalyst, which is prepared by the following method:

[0062] (S1) 0.1 g of Cu(NO3)2·3H2O was dissolved in 10 mL of deionized water, and after stirring uniformly, 1 g of zirconium hydroxide was added, 3 mL of 0.5M NH3·3H2O was added, the pH was adjusted to 10, and stirring was performed for 0.5 h to obtain a blue solution: copper-zirconium precursor solution;

[0063] (S2) The copper-zirconium precursor solution prepared in (S1) was allowed to stand for 1 h, the product was washed with ethanol and water three times, respectively, after the end of washing, it was dried in a vacuum drying oven at 80°C for 12 h, and after the end of drying, it was calcined at 250°C for 3 h to obtain a copper-zirconium bimetallic oxide nanocomposite catalyst (labeled as “K1”).

[0064] The total current density and Faraday efficiency (FE) of the copper-zirconium bimetallic oxide nanocomposite catalyst prepared in the present example at a voltage of -1.9 V vs RHE are shown in Table 1. Figure 4

[0065] Example 7

[0066] The present example provides a copper-zirconium bimetallic oxide nanocomposite catalyst, which is prepared by the following method:

[0067] (S1) 0.1 g of Cu(NO3)2·3H2O was dissolved in 10 mL of deionized water, and after stirring uniformly, 1 g of zirconium hydroxide was added, 3 mL of 0.5M NH3·3H2O was added, the pH was adjusted to 10, and stirring was performed for 0.5 h to obtain a blue solution: copper-zirconium precursor solution;

[0068] (S2) The copper-zirconium precursor solution prepared in (S1) was allowed to stand for 1 h, the product was washed with ethanol and water three times, respectively, after the end of washing, it was dried in a vacuum drying oven at 80°C for 12 h, and after the end of drying, it was calcined at 450°C for 3 h to obtain a copper-zirconium bimetallic oxide nanocomposite catalyst (labeled as “N1”).

[0069] The total current density and Faraday efficiency (FE) of the copper-zirconium bimetallic oxide nanocomposite catalyst prepared in the present example at a voltage of -1.9 V vs RHE are shown in Table 1. Figure 4

[0070] Example 8

[0071] The present example provides a copper-zirconium bimetallic oxide nanocomposite catalyst, which is prepared by the following method: ​​

[0072] (S1) 0.1 g of Cu(N03)2-3H20 was dissolved in 10 mL of deionized water, and after stirring uniformly, 1 g of zirconium hydroxide was added, 3 mL of 0.5 M NH3-3H20 was added, the pH was adjusted to 10, and stirring was performed for 0.5 h to obtain a blue solution: a copper-zirconium precursor solution;

[0073] (S2) The copper-zirconium precursor solution prepared in (S1) was allowed to stand for 1 h, the product was washed with ethanol and water three times, respectively, after the end of the washing, drying was performed in a vacuum drying oven at 80°C for 12 h, and after the end of the drying, calcination was performed at 550°C for 3 h to obtain a copper-zirconium bimetallic oxide nanocomposite catalyst (labeled as “P1”).

[0074] The total current density and the Faraday efficiency (FE) of the copper-zirconium bimetallic oxide nanocomposite catalyst prepared in this example at a voltage of -1.9 V vs RHE are shown in Table 1. Figure 4

[0075] Comparative Example 1

[0076] This comparative example provides a copper catalyst, which is prepared by the following method:

[0077] (S1) 0.1 g of Cu(N03)2-3H20 was dissolved in 10 mL of deionized water, and after stirring uniformly, 3 mL of 0.5 M NH3-3H20 was added, the pH was adjusted to 10, and stirring was performed for 0.5 h to obtain a copper precursor solution;

[0078] (S2) The copper precursor solution prepared in (S1) was allowed to stand for 1 h, the product was washed with ethanol and water three times, respectively, after the end of the washing, drying was performed in a vacuum drying oven at 80°C for 12 h, and after the end of the drying, calcination was performed at 550°C for 3 h to obtain a copper catalyst (labeled as “pure copper”).

[0079] The total current density and the Faraday efficiency (FE) of the catalyst prepared in this comparative example at a voltage of -1.9 V vs RHE are shown in Table 1. Figure 5

[0080] Comparative Example 2

[0081] This comparative example provides a zirconium catalyst, which is prepared by the following method:

[0082] (S1) 1 g of zirconium hydroxide was added to 10 mL of deionized water, and after stirring uniformly, 3 mL of 0.5 M NH3-3H20 was added, the pH was adjusted to 10, and stirring was performed for 0.5 h to obtain a zirconium precursor solution;

[0083] ​​(S2) The zirconium precursor solution prepared in (S1) was left to stand for 1 h, the product was washed with ethanol and water three times respectively, and after the washing was completed, the product was dried in a vacuum drying oven at 80 °C for 12 h to obtain a zirconium catalyst (labeled as "pure zirconium").

[0084] The total current density and Faraday efficiency (FE) of the zirconium catalyst prepared in the present comparative example at a voltage of -1.9 V vs. RHE are shown in Table 1. Figure 5

[0085] Performance analysis:

[0086] The catalysts prepared in Examples 1-8 and Comparative Examples 1-3 were applied to the electrocatalytic CO2 reduction reaction to produce methane:

[0087] 10 mg of the catalyst prepared in Examples 1-5 and Comparative Examples 1-4 was respectively taken into a 3 mL glass bottle, and 970 μL of ethanol and 30 μL of Nafion solution were added into the glass bottle using a pipette with a range of 1000 μL and 100 μL respectively. Subsequently, the glass bottle was placed in an ultrasonic machine for ultrasonic for 1 h until the catalyst was completely dispersed in the solution (ethanol and Nafion solution); the solution was added dropwise onto a 1.0 x 2.5 cm carbon paper multiple times using a pipette with a range of 10 μL, and was dried in an oven at 60 °C, to finally obtain a working electrode.

[0088] The working electrode coated with the catalyst was installed in a flow-type electrolytic cell for electrochemical activity testing, and the applied potential for the electrochemical activity testing was -1.9 V vs. RHE.

[0089] In the flow electrolytic cell, the reference electrode was a saturated Ag / AgCl electrode, the counter electrode was a nickel foam electrode, and 1 M KOH solution was used as the electrolyte in the cathode and anode chambers. In the test, the flow rate of carbon dioxide was controlled at 20 mL·min -1 by a flow controller, and the proton exchange membrane was H + Nafion® provided a channel for the migration of protons to provide the hydrogen source required for the reduction of CO2 to hydrocarbon products. All electrochemical tests were carried out at room temperature and pressure. The entire reaction was a continuous dynamic process, and the reaction products entered a TCD and FID gas chromatograph (Kechuang GC 9800, China) for sampling and analysis, and the experimental results are shown in Table 1.

[0090] Table 1 Summary of the catalytic performance of each catalyst applied to the electrocatalytic CO2 reduction reaction to produce methane

[0091]

[0092] ​It can be found from Table 1 that the copper-zirconium bimetallic oxide nanocomposite catalyst prepared in Example 1 has the highest selectivity to methane product and can significantly inhibit the hydrogen evolution side reaction.

[0093] Figure 3 Faradaic efficiency tests were conducted on the copper-zirconium bimetallic oxide nanocomposite catalysts prepared in Examples 1-5; the tests were conducted by Figure 3 It can be found that the maximum current density of the copper-zirconium bimetallic oxide nanocomposite catalyst prepared in Example 1 is about 346 mA·cm -2 , and a methane selectivity of 78% is achieved.

[0094] The main difference between Example 1 and Examples 2-5 is the amount of Cu(NO3)2·3H2O used in step (S1). Copper is a key active site for electrocatalytic CO2 reduction reaction, and the amount of copper can significantly affect the number of active sites. Too little amount of copper will result in insufficient active sites, and too much amount of copper will enhance the combination ability with H and cause serious hydrogen evolution reaction.

[0095] Figure 4 Faradaic efficiency tests were conducted on the catalysts prepared in Example 1 and Examples 6-8; the tests were conducted by Figure 4 It can be found that the performance of the copper-zirconium bimetallic oxide nanocomposite catalyst prepared in Example 1 is better than that of the catalysts prepared in Examples 6-8.

[0096] The difference between Example 3 and Examples 6-8 is the annealing temperature. As the temperature rises, the catalyst sintering occurs, reducing the contact area of the active components, and the copper particles of different sizes are generated. Moderate copper particle size significantly improves the selectivity to methane and inhibits the hydrogen evolution reaction. The addition of an appropriate amount of zirconium hydroxide at a certain temperature increases the active sites of copper, enhances the adsorption and activation ability of carbon dioxide, and is beneficial to the hydrogenation of CO intermediate to methane.

[0097] Figure 5 Faradaic efficiency tests were conducted on the catalysts prepared in Example 1 and Comparative Examples 1-3; the tests were conducted by Figure 5 It can be found that the performance of the copper-zirconium bimetallic oxide nanocomposite catalyst prepared in Example 1 is better than that of the catalysts prepared in Comparative Examples 1-3.

[0098] The difference between Example 1 and Comparative Example 1 is that Example 1 is a copper-zirconium bimetallic oxide nanocomposite catalyst, and Comparative Example 1 is a pure copper catalyst. Without using zirconium hydroxide as a carrier, the pure copper catalyst does not produce high selectivity for any carbon-containing product, and a serious hydrogen evolution reaction occurs. After adding an appropriate amount of zirconium hydroxide, the selectivity for methane is significantly improved, and the hydrogen evolution reaction is inhibited. This is because the Zr in the copper-zirconium bimetallic oxide nanocomposite catalyst can prevent CuO particles from aggregating, promote Cu dispersion, enhance CO2 activation, thereby promoting the protonation of CO intermediates, inhibiting C-C coupling, and improving the selectivity of electrocatalytic CO2 reduction to methane.

[0099] The difference between Example 1 and Comparative Example 2 is that Example 1 is a copper-zirconium bimetallic oxide nanocomposite catalyst, and Comparative Example 2 is a pure zirconium catalyst. The pure zirconium hydroxide catalyst has no selectivity for methane, and all hydrogen evolution reactions occur. After compounding copper and zirconium hydroxide, CO formed on the zirconium hydroxide is transferred to the copper site, which is conducive to the hydrogenation reaction and the generation of methane. In general, the copper-zirconium bimetallic oxide nanocomposite catalyst provided by the present application has broad application prospects in the application of electrocatalytic CO2 reduction to methane.

[0100] Example 9

[0101] The present embodiment provides a copper-zirconium bimetallic oxide nanocomposite catalyst, which is prepared by the following method:

[0102] (S1) 0.1 g of copper chloride is dissolved in 10 mL of deionized water, and after stirring uniformly, 1 g of zirconium hydroxide is added, NH3·3H2O is added to adjust the pH to 9, and stirring is performed for 1 h to obtain a blue solution: copper-zirconium precursor solution;

[0103] (S2) The copper-zirconium precursor solution prepared in (S1) is allowed to stand for 0.5 h, the product is washed with ethanol and water three times, respectively, after the end of the washing, the product is dried in a vacuum drying oven at 60°C for 14 h, and after the end of the drying, the product is calcined at 200°C for 6 h to obtain a copper-zirconium bimetallic oxide nanocomposite catalyst.

[0104] Example 10

[0105] The present embodiment provides a copper-zirconium bimetallic oxide nanocomposite catalyst, which is prepared by the following method:

[0106] (S1) 0.1 g of copper carbonate hydroxide is dissolved in 10 mL of deionized water, and after stirring uniformly, 1 g of zirconium hydroxide is added, NH3·3H2O is added to adjust the pH to 11, and stirring is performed for 0.8 h to obtain a blue solution: copper-zirconium precursor solution;

[0107] (S2) The copper-zirconium precursor solution prepared in (S1) was left to stand for 1.5 h, the product was washed with ethanol and water respectively for 3 times, after the washing was finished, the product was dried in a vacuum drying oven at 70°C for 12 h, after the drying was finished, the product was calcined at 600°C for 2 h, and a copper-zirconium bimetallic oxide nanocomposite catalyst was obtained.

[0108] The copper-zirconium bimetallic oxide nanocomposite catalyst prepared in Examples 9-10 has a performance comparable to that of the copper-zirconium bimetallic oxide nanocomposite catalyst prepared in Example 2.

[0109] Comparative Example 3

[0110] The present comparative example provides a copper-zirconium bimetallic oxide nanocomposite catalyst, which is prepared by the following method:

[0111] (S1) 0.1 g of Cu(NO3)2·3H2O was dissolved in 10 mL of deionized water, after being stirred uniformly, 1 g of zirconium oxide was added, 3 mL of 0.5M NH3·3H2O was added, the pH was adjusted to 10, and the stirring was performed for 0.5 h to obtain a blue solution: copper-zirconium precursor solution;

[0112] (S2) The copper-zirconium precursor solution prepared in (S1) was left to stand for 1 h, the product was washed with ethanol and water respectively for 3 times, after the washing was finished, the product was dried in a vacuum drying oven at 80°C for 12 h, after the drying was finished, the product was calcined at 350°C for 3 h, and a copper-zirconium bimetallic oxide nanocomposite catalyst was obtained.

[0113] Compared with the copper-zirconium bimetallic oxide nanocomposite catalyst prepared in Example 1, the copper-zirconium bimetallic oxide nanocomposite catalyst prepared in the present comparative example was found to have a performance far worse than that of the copper-zirconium bimetallic oxide nanocomposite catalyst prepared in Example 1.

[0114] The above description of the comparative examples is for the purpose of enabling and using the invention for those of ordinary skill in the art. Those skilled in the art can easily make various modifications to these examples, and apply the general principles described herein to other examples without having to go through creative labor. Therefore, the present invention is not limited to the above examples, and improvements and modifications made by those skilled in the art without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A method for preparing a copper-zirconium bimetallic oxide nanocomposite catalyst, characterized by, The method comprises the following steps: (S1) dissolving and mixing copper precursor salt and zirconium hydroxide and adjusting pH to obtain copper-zirconium precursor solution; (S2) post-treating and calcining the copper-zirconium precursor solution prepared in step (S1) to obtain copper-zirconium bimetallic oxide nanocomposite catalyst.

2. The method for preparing a copper-zirconium bimetallic oxide nanocomposite catalyst according to claim 1, characterized in that, In step (S1), the copper precursor salt is selected from one or more of copper chloride, copper nitrate trihydrate, basic copper carbonate and copper acetate.

3. The method for preparing a copper-zirconium bimetallic oxide nanocomposite catalyst according to claim 1, characterized in that, In step (S1), the mass ratio of copper precursor salt to zirconium hydroxide is 0.01-0.5:

1.

4. The method for preparing a copper-zirconium bimetallic oxide nanocomposite catalyst according to claim 2, characterized in that, In step (S1), the temperature during mixing is room temperature and the time is 0.5-1 h.

5. The method for preparing a copper-zirconium bimetallic oxide nanocomposite catalyst according to claim 1, characterized in that, In step (S1), the pH of the copper-zirconium precursor solution is adjusted to 9-11 using ammonia solution.

6. The method for preparing a copper-zirconium bimetallic oxide nanocomposite catalyst according to claim 1, characterized in that, In step (S2), the post-treatment comprises sequentially standing, washing and drying the copper-zirconium precursor solution.

7. The method for preparing a copper-zirconium bimetallic oxide nanocomposite catalyst according to claim 6, characterized in that, In the standing process, the temperature is room temperature and the time is 0.5-1.5 h; In the washing process, the copper-zirconium precursor solution is washed with ethanol and deionized water several times respectively; In the drying process, the temperature is 60-80℃ under vacuum and the time is 10-14 h.

8. The method for preparing a copper-zirconium bimetallic oxide nanocomposite catalyst according to claim 1, characterized in that, In step (S2), the calcination temperature is 200-600℃ and the time is 2-6 h.

9. A copper-zirconium bimetallic oxide nanocomposite catalyst characterized by, The copper-zirconium bimetallic oxide nanocomposite catalyst is prepared by the method of any one of claims 1-8.

10. Use of the copper-zirconium bimetallic oxide nanocomposite catalyst of claim 9 in electrocatalytic CO2 reduction to produce methane.

Images