A Cu-ZnO@Al2O3 catalyst and its preparation method and application

Abstract

The present invention discloses a Cu-ZnO@Al2O3 catalyst, its preparation method, and application, belonging to the technical field of catalyst preparation. The present invention utilizes a coprecipitation method and a calcination reduction method to prepare the Cu-ZnO@Al2O3 catalyst. Based on Cu as the active component, Zn and Al oxides are introduced to enable the Cu-ZnO@Al2O3 catalyst to exhibit a relatively large number of L-acid sites, thereby promoting C-O bond cleavage during the electrocatalytic hydrogenation of furfural. Ultimately, relatively excellent catalytic performance is achieved for the highly selective electroreduction of furfural to 2-methylfuran. At a constant voltage reaction of 0.5 V vs. SHE for 1 hour, the selectivity for 2-methylfuran is 95%. This also avoids the rapid deactivation and steep current drop problems associated with elemental Cu as a cathode electrode material.

Description

Technical Field

[0001] The present invention belongs to the technical field of catalyst preparation, and in particular relates to a Cu-ZnO@Al2O3 catalyst and a preparation method and application thereof. Background Art

[0002] Furfural is a key product in the biorefining industry, and value-added products derived from furfural (such as 2-methylfuran) are widely used in the chemical and energy industries. Traditional methods for reducing furfural are hydrodeoxygenation and catalytic hydrogen transfer, but both have some disadvantages, such as the use of high-pressure hydrogen, toxic reducing agents, or the need for high-temperature reaction conditions during the reduction process. Electrochemical hydrogenation provides a sustainable reduction method for reducing furfural to 2-methylfuran. In the electrochemical reduction process, the hydrogen source comes from water or protons in the solution, and renewable energy electricity can be used to convert the water or protons in the solution into adsorbed hydrogen. The adsorbed hydrogen is adsorbed on the electrode surface and further undergoes the furfural hydrogenation reaction under mild reaction conditions. However, due to the competition of side reactions in the electrochemical hydrogenation of furfural, the electrochemical reduction method to obtain 2-methylfuran still has problems such as low activity and Faraday efficiency.

[0003] A series of catalysts have been developed for the electrocatalytic hydrogenation of furfural, such as Cu, Pb, Fe, Pt, Pd, Ti and graphite. Among them, Cu is the most promising because it is non-precious metal and has high selectivity. However, when Cu is used alone as a catalyst, the current decays too quickly, resulting in a low conversion rate Faraday efficiency. In the prior art, a series of CuPd catalysts are used to electrochemically hydrogenate furfural to 2-methylfuran in a 0.1M acetic acid aqueous solution (pH = 2.9). At -0.58V vs RHE, the highest Faraday efficiency (FE) of 2-methylfuran reaches 75%, but the current density at this time is only -4.5mA / cm 2 , the reaction current is too small. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a Cu-ZnO@Al2O3 catalyst and its preparation method and application, so as to solve the technical problem of low selectivity of furfural electroreduction.

[0005] To achieve the above object, the technical solution adopted by the present invention is: to provide a method for preparing a Cu-ZnO@Al2O3 catalyst, comprising the following steps:

[0006] S1. Dissolve copper salt, zinc salt, and aluminum salt in water to obtain a mixed solution, then add the mixed solution to a carbonate solution at 35-45°C, adjust the pH value of the reaction system to 9-10, and finally raise the temperature to 55-85°C and react for 12-24 hours, centrifuge, and obtain a precipitate; the molar ratio of Cu, Zn, and Al ions in the mixed solution is 2-6:1-3:1-3;

[0007] S2. Dry the precipitate at 60-100°C for 12-48 hours, then heat it to 500-900°C and calcine it for 2-8 hours. Finally, reduce the calcined sample in a reducing atmosphere at 500-900°C for 2-6 hours to obtain a Cu-ZnO@Al2O3 catalyst.

[0008] On the basis of the above technical solution, the present invention can also be improved as follows:

[0009] Furthermore, the copper salt is copper nitrate, copper sulfate or copper chloride, the zinc salt is zinc nitrate, zinc sulfate or zinc chloride, and the aluminum salt is aluminum nitrate, aluminum sulfate or aluminum chloride.

[0010] Furthermore, the carbonate solution is a sodium carbonate or potassium carbonate solution.

[0011] Furthermore, the reagent for adjusting the pH value of the reaction system is NaOH or KOH solution.

[0012] Furthermore, the reaction temperature in S1 is 70° C. and the reaction time is 18 h.

[0013] Furthermore, S2 also includes washing the precipitate to neutrality before drying.

[0014] Furthermore, the calcination temperature in S2 is 500° C., and the calcination time is 4 h; the reduction temperature is 500° C., and the reduction time is 2 h.

[0015] Furthermore, the gases used in the reducing atmosphere are H2 and N2.

[0016] Furthermore, the flow rate of H2 is 5-15 mL / min, and the flow rate of N2 is 85-95 mL / min.

[0017] The invention also discloses a Cu-ZnO@Al2O3 catalyst prepared by the preparation method.

[0018] The invention also discloses the application of Cu-ZnO@Al2O3 catalyst in furfural reduction.

[0019] The beneficial effects of the present invention are as follows: the Cu-ZnO@Al2O3 catalyst prepared by the present invention has a large number of L-acid sites, thereby promoting the cleavage of the CO bond during the electrocatalytic hydrogenation of furfural, and ultimately obtaining relatively excellent catalytic performance for the electroreduction of furfural with high selectivity to produce 2-methylfuran. The use of acidic oxides such as Al2O3, ZSM-5 and SiO2 as carriers can improve the selectivity of Cu-ZnO-catalyzed furfural hydrogenation to produce 2-methylfuran. In a 0.5M H2SO4 solution, the catalyst exhibits efficient furfural electroreduction to produce 2-methylfuran. At a constant voltage reaction of -0.5V vs. SHE for 1 hour, the selectivity of 2-methylfuran is 95%. At the same time, the problems of rapid deactivation and steep current drop of elemental Cu as a cathode electrode material are avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is the XRD pattern of Cu;

[0021] Figure 2 is the XRD pattern of ZnO;

[0022] Figure 3 is the XRD pattern of Cu-ZnO;

[0023] Figure 4 This is the XRD pattern of Cu-ZnO@Al2O3.

[0024] Figure 5 This is the high-resolution XPS spectrum of Zn in Cu-ZnO@Al2O3;

[0025] Figure 6 This is the high-resolution XPS spectrum of Cu in Cu-ZnO@Al2O3;

[0026] Figure 7 This is the high-resolution XPS spectrum of Al in Cu-ZnO@Al2O3;

[0027] Figure 8 The morphological characteristics of Cu-ZnO@Al2O3; Figure (a) is a TEM image at 50nm, Figure (b) is a TEM image at 10nm, Figure (c) is a mapping scan of Cu-ZnO@Al2O3, Figure (d) is a mapping scan of the O element, Figure (e) is a mapping scan of the Al element, Figure (f) is a mapping scan of the Cu element, and Figure (g) is a mapping scan of the Zn element;

[0028] Figure 9 The effect of aluminum nitrate concentration on the furfural conversion and 2-methylfuran Faraday efficiency of Cu-ZnO@Al2O3 catalyst;

[0029] Figure 10 The effect of aluminum nitrate concentration on the selectivity of furfural reduction products over Cu-ZnO@Al2O3 catalyst;

[0030] Figure 11 XRD patterns of Cu-ZnO@Al2O3 catalysts prepared at different zinc nitrate concentrations;

[0031] Figure 12 Effect of zinc nitrate concentration on furfural conversion and 2-methylfuran Faraday efficiency over Cu-ZnO@Al2O3 catalyst;

[0032] Figure 13 The effect of zinc nitrate concentration on the selectivity of furfural reduction products over Cu-ZnO@Al2O3 catalyst;

[0033] Figure 14 NH3-TPD spectra of Cu and Cu-ZnO@Al2O3 catalysts;

[0034] Figure 15 The product selectivity of materials prepared based on different acidic oxides;

[0035] Figure 16 LSV curves of Cu-ZnO@Al2O3 and Cu and Zn metal sheets before and after adding furfural;

[0036] Figure 17 The product selectivity of Cu-ZnO@Al2O3 and Cu and Zn metal sheets;

[0037] Figure 18 It curve of the constant voltage reaction between Cu-ZnO@Al2O3 and Cu metal sheet;

[0038] Figure 19 LSV curves of Cu-ZnO@Al2O3 and Cu, ZnO and Al2O3 powders before and after adding furfural;

[0039] Figure 20 The product selectivity of Cu-ZnO@Al2O3 and Cu, ZnO and Al2O3 powders. DETAILED DESCRIPTION

[0040] The specific embodiments of the present invention are described below to facilitate understanding of the present invention by those skilled in the art. In the examples, where specific conditions are not specified, the experiments were carried out under conventional conditions or conditions recommended by the manufacturer. Reagents or instruments used where the manufacturer is not specified are conventional products that can be purchased commercially. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. It is obvious to those skilled in the art that various modifications are within the spirit and scope of the present invention as defined and determined by the appended claims, and all inventions and creations utilizing the present invention are protected.

[0041] Example 1

[0042] A method for preparing a Cu-ZnO@Al2O3 catalyst comprises the following steps:

[0043] S1. Dissolve 12.1245 g of Cu(NO3)2·3H2O, 7.43725 g of Zn(NO3)2·6H2O and 9.37825 g of Al(NO3)3·9H2O in 100 mL of water to obtain a mixture (0.5 M Cu(NO3)2·3H2O, 0.25 M Zn(NO3)2·6H2O and 0.25 M Al(NO3)3·9H2O). Then, add the mixture to a 100 mL sodium carbonate solution with a concentration of 0.125 M at 40°C to make Cu(NO3)2·3H2O. 2+ 、Zn 2+ 、Al 3+ It was converted into carbonate precipitate, and the pH value of the reaction system was adjusted to 9.5 with a 1M NaOH solution to form a layered structure. Finally, the temperature was raised to 70°C and reacted for 18 hours, and centrifuged to obtain a precipitate.

[0044] S2. The precipitate was washed with ethanol and deionized water until neutral, and then the precipitate was dried at 80°C for 30 hours, then heated to 500°C and calcined for 4 hours. Finally, the calcined sample was placed in a reducing atmosphere (a mixed atmosphere of H2 and N2, with a flow rate of H2 of 10 mL / min and a flow rate of N2 of 90 mL / min) and reduced at 500°C for 2 hours to obtain a Cu-ZnO@Al2O3 catalyst.

[0045] Example 2

[0046] A method for preparing a Cu-ZnO@Al2O3 catalyst comprises the following steps:

[0047] S1. Dissolve 12g CuSO4·3H2O, 7g ZnSO4·6H2O and 9g Al2(SO4)3·9H2O in 100mL water to obtain a mixture. Then add the mixture into 100mL sodium carbonate solution with a concentration of 0.125M at 35℃. 2 + 、Zn 2+ 、Al 3+ The solution was converted into carbonate precipitate, and the pH value of the reaction system was adjusted to 10 with 1M NaOH solution to form a layered structure. The solution was then heated to 55°C and reacted for 24 hours. The solution was centrifuged to obtain a precipitate.

[0048] S2. The precipitate was washed with ethanol and deionized water until neutral, and then the precipitate was dried at 100°C for 12 hours, then heated to 700°C and calcined for 8 hours. Finally, the calcined sample was placed in a reducing atmosphere (a mixed atmosphere of H2 and N2, with a flow rate of H2 of 5 mL / min and a flow rate of N2 of 95 mL / min) and reduced at 700°C for 4 hours to obtain a Cu-ZnO@Al2O3 catalyst.

[0049] Example 3

[0050] A method for preparing a Cu-ZnO@Al2O3 catalyst comprises the following steps:

[0051] S1. Dissolve 13g CuCl2·3H2O, 7g ZnCl2·6H2O and 9g AlCl3·9H2O in 100mL water to obtain a mixture. Then add the mixture to a 0.125M potassium carbonate solution in a volume of 100mL at 45℃ to make CuCl2·3H2O and ZnCl2·6H2O. 2+ 、Zn 2+ 、Al 3+ It was converted into carbonate precipitate, and the pH value of the reaction system was adjusted to 9 with a 1M KOH solution to form a layered structure. Finally, the temperature was raised to 85°C and reacted for 12 hours, and centrifuged to obtain a precipitate.

[0052] S2. The precipitate was washed with ethanol and deionized water until neutral, and then the precipitate was dried at 60°C for 48 hours, then heated to 900°C and calcined for 2 hours. Finally, the calcined sample was placed in a reducing atmosphere (a mixed atmosphere of H2 and N2, with a flow rate of H2 of 15 mL / min and a flow rate of N2 of 85 mL / min) and reduced at 900°C for 2 hours to obtain a Cu-ZnO@Al2O3 catalyst.

[0053] Comparative Example 1

[0054] The difference between this comparative example and Example 1 is that Zn(NO3)2·6H2O and Al(NO3)3·9H2O in step S1 are omitted, and the remaining components are the same as the preparation method and Example 1 to prepare a Cu catalyst.

[0055] Comparative Example 2

[0056] The difference between this comparative example and Example 1 is that Cu(NO3)2·3H2O and Al(NO3)3·9H2O in step S1 are omitted, and the remaining components are the same as the preparation method and Example 1 to prepare a ZnO catalyst.

[0057] Comparative Example 3

[0058] The difference between this comparative example and Example 1 is that Al(NO3)3·9H2O in step S1 is omitted, and the remaining components are the same as the preparation method and Example 1 to prepare a Cu-ZnO catalyst.

[0059] Experimental Example 1 Structural Characterization

[0060] 1.XRD test

[0061] The catalyst samples prepared in Example 1 and Comparative Examples 1-3 were subjected to XRD testing to analyze the component information and crystal structure of the catalysts. The results are as follows: Figure 1-Figure 4 shown.

[0062] like Figure 1 As shown in Figure 4, the XRD diffraction peaks at 43.3°, 50.4°, 74.1°, and 89.9° correspond to the (1 1 1), (2 0 0), (2 2 0), and (3 1 1) crystal planes of elemental Cu, respectively (PDF#4-836). Figure 4 As shown in the figure, the diffraction peaks at positions such as 31.7°, 34.4°, 36.2°, and 47.5° correspond to the (1 0 0), (0 0 2), (1 0 1), and (1 0 2) crystal planes of ZnO and the diffraction peaks of Al2O3, respectively. Comparison with the standard card (PDF#10-0425) reveals that the Al2O3 present in the catalyst prepared in Example 1 is γ phase. This shows that Cu in Cu-ZnO@Al2O3 exists in the form of a single substance, while Zn and Al exist in the form of oxides.

[0063] 2.XPS test

[0064] XPS tests were performed to investigate the elemental composition and chemical state of the Cu-ZnO@Al2O3 catalyst surface. Figure 5 ) It can be seen that the peaks at 1044.8eV and 1022.1eV are closely related to the Zn 2+ Related, combined with the XRD spectrum of Cu-ZnO@Al2O3 ( Figure 4 ) can indicate that during the preparation process, Zn oxide is not reduced because it has not reached its reduction temperature, so zinc exists in the form of ZnO. Figure 6 This is the XPS spectrum of Cu element. In addition to the characteristic peak of CuO, there are two significant Cu 2p peaks in the Cu 2p spectrum. 2+ Satellite peaks may be caused by oxidation of Cu surface during the test. Figure 7 ) It can be seen that the form of Al is Al 3+ This is also because the reduction temperature during the preparation process did not reach the reduction temperature of Al2O3 (900℃).

[0065] 3.TEM test

[0066] The surface structure and morphology of Cu-ZnO@Al2O3 catalyst were characterized by transmission electron microscopy (TEM). Figure 8 As shown. Figure 8 (a) It can be seen that the Cu-ZnO@Al2O3 catalyst exhibits a nanosheet structure; Figure 8 (b) shows lattice fringes with spacing of 0.288 nm and 0.278 nm, which correspond to the ZnO (1 1 0) crystal plane and the Al2O3 (22 2) crystal plane, respectively.

[0067] The element distribution of Cu-ZnO@Al2O3 catalyst was further studied by mapping scan, such as Figure 8 (c)- Figure 8 As shown in (g), the elements are distributed relatively evenly.

[0068] Experimental Example 2 Optimization of catalyst preparation conditions

[0069] The following experiments were performed using the preparation process of Example 1 as an example:

[0070] 1. Aluminum nitrate concentration

[0071] With other conditions unchanged, the concentration of aluminum nitrate was changed (0.125M, 0.25M, 0.375M and 0.5M) to prepare a series of Cu-ZnO@Al2O3 catalysts with different aluminum contents. Figure 9 and Figure 10 As shown in the figure, as the amount of added Al2O3 increases, the furfural conversion, 2-methylfuran selectivity, and Faradaic efficiency all increase first and then decrease, reaching their maximum values at an aluminum nitrate concentration of 0.25 M. This is because Al2O3 has poor conductivity. When Al2O3 is too much, the conductivity of the catalyst deteriorates, affecting the conversion of furfural and the formation of 2-methylfuran.

[0072] 2. Concentration of zinc nitrate

[0073] The effect of ZnO on the reduction activity of furfural was investigated by introducing different amounts of ZnO. The introduction of ZnO can increase the L-acid concentration of Al2O3. At the same time, the presence of Zn will inhibit the sintering of metal particles and act as a dispersant for other metal substances. Under the condition that other conditions remain unchanged, the concentration of zinc nitrate is changed (0M, 0.125M, 0.25M, 0.5M and 1M) to prepare a series of Cu-ZnO@Al2O3 catalysts with different ZnO contents. The results are shown in Figure 2. Figure 11 As shown in the figure, with the increase of zinc nitrate concentration, the peak intensity of ZnO becomes higher and higher, and the crystallinity becomes higher and higher, that is, the proportion of zinc oxide in the catalyst increases. Figure 12 and Figure 13 It shows that the optimal concentration of zinc nitrate is 0.25M. When the concentration is too high, the furfural conversion rate drops sharply. This is because the addition of too much ZnO reduces the number of active sites and the conductivity of the catalyst, thereby reducing the reduction current of furfural.

[0074] Experimental Example 3 Catalyst Activity Analysis

[0075] In order to explore the mechanism of ZnO and Al2O3 on the performance improvement of Cu-ZnO@Al2O3 catalyst, this experiment conducted NH3-TPD test on Cu-ZnO@Al2O3 material. Figure 14 As shown in the figure, it is obvious that the Cu powder alone is not acidic, but after adding ZnO and Al2O3, the Cu-ZnO@Al2O3 material shows strong acidity.

[0076] Using commercial Al2O3, ZSM-5 (silicon aluminum molecular sieve) and SiO2 three acidic oxide powders as substrates, the aluminum salt in Example 1 was replaced with different acidic oxide powders to prepare Cu-ZnO / Al2O3, Cu-ZnO / ZSM-5, and Cu-ZnO / SiO2 catalysts. The catalyst was used as the cathode and constant voltage electrolysis was performed at -0.5V vs. SHE voltage. The product distribution results are shown as follows: Figure 15 As shown in the figure, although the catalytic activity of the three catalysts prepared with different substrates (Cu-ZnO / Al2O3, Cu-ZnO / ZSM-5, and Cu-ZnO / SiO2) is not as good as that of the Cu-ZnO@Al2O3 catalyst prepared in Example 1, the selectivity of 2-methylfuran is significantly improved in the catalysts with the addition of the three acidic substrates of Al2O3, ZSM-5, and SiO2 compared to the Cu-ZnO catalyst without the addition of the acidic oxide. This shows that increasing the acidity of the catalyst helps to improve the selectivity of 2-methylfuran.

[0077] Experimental Example 4 Furfural electroreduction performance test

[0078] The furfural reduction performance was tested using a three-electrode system (working electrode, counter electrode, and reference electrode) in an H-type electrolytic cell with a proton membrane separating the anode and cathode. The working electrode was the sample to be tested, with an electrode working area of 1 cm × 1 cm, the counter electrode was a dimensionally stable anode DSA with an area of 2 cm × 2 cm, and the reference electrode was Ag / AgCl. The anode and cathode were both 30 mL, 0.5 M H2SO4 electrolyte solution, the concentration of furfural, the organic matter in the cathode reaction, is 20mM. With the standard hydrogen electrode (SHE) as a reference, all experiments were carried out at 40°C, CV tests were performed at 100mv / s, and LSV tests were performed at 5mv / s. The H-type electrolyzer was connected to a Mengke washing bottle filled with 30mL acetonitrile as a 2-methylfuran collector, and the exhaust gas treatment device was connected after the collector. N2 was used as a purge gas throughout the reaction. The target product 2-methylfuran was collected by the collector, and after adding the internal standard, it was detected by gas chromatography, while the raw material furfural and the by-product furfuryl alcohol were detected by high performance liquid chromatography.

[0079] The furfural reduction activity of Zn, Cu electrode sheets, blank carbon paper and Cu-ZnO@Al2O3 catalyst was compared. In the electrolyte without furfural, the cathodic polarization curve was attributed to the hydrogen evolution reaction. Figure 16 As shown in the figure, as the electrode potential moves toward the negative direction, the HER activity advantage of the Cu metal sheet becomes increasingly apparent compared to that of Cu-ZnO@Al2O3. When 20 mM furfural is added to the electrolyte, the electroreduction material on the cathode of all materials shifts toward the positive direction, indicating that the furfural reduction reaction on all electrode materials is faster than the hydrogen evolution reaction. Although the hydrogen evolution activity of Cu is generally better than that of the Cu-ZnO@Al2O3 catalyst over the entire test voltage range, after the addition of furfural, the Cu-ZnO@Al2O3 cathode shows a significant increase in current density within the same scanning potential range, indicating a greater improvement in furfural reduction activity. In addition, the furfural reduction activity of Cu-ZnO@Al2O3 is better than that of the Cu metal sheet in the range of -0.2 to -0.5 V vs. SHE.

[0080] The performance of furfural conversion, selectivity and Faraday efficiency when Cu-ZnO@Al2O3 and Cu and Zn metal sheets were used as cathode electrodes was investigated by reacting at a constant potential of -0.5V vs SHE for 1h. Figure 17 As shown in the figure, furfural is converted to 2-methylfuran with the highest selectivity (95%). Although the highest selectivity of Cu metal sheet can reach over 90%, the current decay is still too fast on the Cu metal sheet. The current stability of Cu-ZnO@Al2O3 catalyst is significantly improved ( Figure 18 ), avoiding the problem of rapid deactivation and steep current drop of single-element Cu as cathode electrode material.

[0081] By comparing the furfural electroreduction performance of catalysts with different compositions, the results are as follows: Figure 19 and Figure 20 As shown. Figure 19 It was observed that when no organic matter was added, the hydrogen evolution activity of Cu / CP was higher than that of Cu-ZnO@Al2O3 catalyst. However, after adding 20mM furfural, the current density of Cu-ZnO@Al2O3 was higher than that of Cu / CP in the voltage range of -0.2 to 0.5V vs SHE. Figure 20 It can be seen that the selectivity of the product 2-methylfuran after constant potential electrolysis is Cu

Claims

1. Application of a Cu-ZnO@Al2O3 catalyst in the electrocatalytic reduction of furfural, characterized in that: The preparation steps of the Cu-ZnO@Al2O3 catalyst include: S1. Dissolving a copper salt, a zinc salt, and an aluminum salt in water to obtain a mixed solution, then adding the mixed solution to a carbonate solution at 35-45° C., adjusting the pH value of the reaction system to 9-10, and finally heating to 55-85° C. for reaction for 12-24 hours, centrifuging, and obtaining a precipitate; the molar ratio of Cu, Zn, and Al ions in the mixed solution is 2-6:1-3:1-3; and the reagent for adjusting the pH value of the reaction system is a NaOH or KOH solution; S2. Dry the precipitate at 60-100°C for 12-48 hours, then heat it to 500-900°C and calcine it for 2-8 hours. Finally, reduce the calcined sample in a reducing atmosphere at 500-900°C for 2-6 hours to obtain a Cu-ZnO@Al2O3 catalyst.

2. The use of the Cu-ZnO@Al2O3 catalyst in the electrocatalytic reduction of furfural according to claim 1, characterized in that: The copper salt is copper nitrate, copper sulfate or copper chloride, the zinc salt is zinc nitrate, zinc sulfate or zinc chloride, and the aluminum salt is aluminum nitrate, aluminum sulfate or aluminum chloride.

3. The use of the Cu-ZnO@Al2O3 catalyst in the electrocatalytic reduction of furfural according to claim 1, characterized in that: The reaction temperature in S1 is 70° C. and the reaction time is 18 h.

4. The use of the Cu-ZnO@Al2O3 catalyst in the electrocatalytic reduction of furfural according to claim 1, characterized in that: The step S2 also includes washing the precipitate to a neutral state before drying.

5. The use of the Cu-ZnO@Al2O3 catalyst in the electrocatalytic reduction of furfural according to claim 1, characterized in that: In the S2, the calcination temperature is 500° C. and the calcination time is 4 h; the reduction temperature is 500° C. and the reduction time is 2 h.

6. Use of the Cu-ZnO@Al2O3 catalyst in the electrocatalytic reduction of furfural according to claim 1, characterized in that: The gases used in the reducing atmosphere are H2 and N2.

7. Use of the Cu-ZnO@Al2O3 catalyst in the electrocatalytic reduction of furfural according to claim 6, characterized in that: The flow rate of H2 is 5-15 mL / min, and the flow rate of N2 is 85-95 mL / min.

Images