Surface amorphized metal oxide nanoparticle catalysts, methods of making and use

Abstract

The present disclosure provides a surface amorphous metal oxide nanoparticle catalyst, a preparation method and an application, and belongs to the field of nanometer catalyst preparation, wherein the surface amorphous metal oxide nanoparticle catalyst comprises: a crystalline metal oxide nanoparticle core; and an amorphous metal oxide nanometer layer; wherein the crystalline metal oxide nanoparticle core is wrapped by the amorphous metal oxide nanometer layer.

Description

TECHNICAL FIELD

[0001] The present disclosure belongs to the field of nanometer and sub-nanometer material preparation, and particularly relates to a surface-amorphized metal oxide nanoparticle catalyst, a preparation method and application. BACKGROUND

[0002] In recent years, due to the increasing emission of carbon dioxide (CO2), the conversion and utilization of carbon dioxide has become the focus of researchers, in which electrochemical CO2 reduction provides a sustainable way for the storage of intermittent renewable energy, and the main products are carbon monoxide (CO), formic acid (HCOOH), ethanol (C2H5OH), ethylene (C2H4), acetic acid (CH3COOH), isopropyl alcohol (C3H8OH) and the like. Among them, the related carbon dioxide electro-reduction catalysts such as Ag, Zn mainly obtain CO products, and the related catalysts such as Sn, Bi, In mainly obtain HCOOH products. As for multi-carbon products, only copper-based materials can obtain multi-carbon products such as ethanol and ethylene at a high current density. Although multi-carbon products have high energy density and economic value, in the process of electrochemical production of multi-carbon products by using carbon dioxide, the formation of C-C bond is involved, accompanied by the transfer of multiple electrons and protons, and at a large current density, the competitive reaction of hydrogen evolution is easy to occur, which affects the production of multi-carbon products. SUMMARY

[0003] Therefore, in order to solve the above technical problems, the present disclosure provides a surface-amorphized metal oxide nanoparticle catalyst, a preparation method and application, so as to at least partially solve the above technical problems.

[0004] In order to solve the above technical problems, the technical solutions provided are as follows:

[0005] As a first aspect of the present disclosure, a surface-amorphized metal oxide nanoparticle catalyst is provided, comprising:

[0006] a crystalline metal oxide nanoparticle core; and

[0007] an amorphous metal oxide nanolayer;

[0008] The crystalline metal oxide nanoparticle core is wrapped by the amorphous metal oxide nanolayer.

[0009] In one embodiment, the thickness of the amorphous metal oxide nanolayer is 1-10 nm, and the surface has coordination unsaturated defects;

[0010] The particle size of the crystalline metal oxide nanoparticle core is 50-500 nm.

[0011] In one of the embodiments, the metal oxide is a single metal oxide, a binary metal oxide, or a ternary metal oxide, or a combination thereof,

[0012] wherein the metal in the single metal oxide is selected from any one of Fe, Co, Ni, Cu, Zn, Mn, Ag, In, Sn, Ir, Pb, Bi; or

[0013] the binary metal in the binary metal oxide is any one combination of FeCo, FeNi, CuCo, CuZn, CuSn, CuPb, InSn, SnBi; or

[0014] the ternary metal in the ternary metal oxide is any one combination of CuZnMn, CuZnSn.

[0015] In one of the embodiments, the molar ratio of the two metals in the binary metal oxide is 5:1-1:5;

[0016] the molar ratio of the three metals in the ternary metal oxide is 5:1:1-5:5:1 or 1:5:1-1:1:5.

[0017] As a second aspect of the disclosure, a method for preparing a surface-amorphous metal oxide nanoparticle catalyst is provided, comprising:

[0018] mixing the metal salt precursor with the salt template by ball milling to obtain a uniformly dispersed mixture precursor;

[0019] placing the mixture precursor in a reactor, and performing calcination under a mixed atmosphere of argon and oxygen at a first preset temperature to obtain the surface-amorphous metal oxide nanoparticle catalyst.

[0020] In one of the embodiments, the metal salt precursor comprises at least one of:

[0021] iron salt, cobalt salt, nickel salt, copper salt, zinc salt, manganese salt, silver salt, indium salt, tin salt, iridium salt, lead salt, bismuth salt;

[0022] The salt template is potassium salt, and the potassium salt comprises any one of:

[0023] potassium bicarbonate, potassium nitrate, potassium bromide, potassium carbonate.

[0024] In one of the embodiments, the metal salt precursor comprises at least one of:

[0025] iron acetylacetone, iron nitrate nine water, cobalt acetylacetone, cobalt nitrate six water, nickel acetylacetone, nickel nitrate six water, copper hydroxide, copper nitrate three water, copper acetylacetone, zinc acetylacetone, manganese acetylacetone, silver acetylacetone, indium acetylacetone, tin acetylacetone, iridium acetylacetone, lead acetylacetone, bismuth nitrate five water;

[0026] The molar ratio of the metal salt precursor to the potassium salt template is 5:1 to 25:1.

[0027] In one embodiment, the parameters for ball milling the metal salt precursor and the salt template include:

[0028] The mixing ball mill speed is 200-1000 rpm;

[0029] The mixing and milling time includes 2-20 hours.

[0030] In one embodiment, the oxygen content in the argon and oxygen mixture is 5-50%, and the flow rate of the mixture is 10-150 sccm.

[0031] The parameters for calcination at the first preset temperature include:

[0032] The first preset temperature range includes: 280-700℃;

[0033] The heating rate for calcination ranges from 2 to 20 °C / min;

[0034] The calcination time includes 1-5 hours.

[0035] As a third aspect of this disclosure, the application of surface-amorphous metal oxide nanoparticle catalysts includes:

[0036] A surface-amorphized metal oxide nanoparticle catalyst was applied to the electrochemical reduction of carbon dioxide to prepare multi-carbon products.

[0037] Among them, multi-carbon products include any one of the following:

[0038] Ethylene, ethanol, acetic acid, isopropanol.

[0039] Based on the above technical solution, the surface amorphous metal oxide nanoparticle catalyst, its preparation method, and its application provided in this disclosure have at least one of the following beneficial effects:

[0040] (1) According to the embodiments of this disclosure, an amorphous metal oxide nanolayer is coated on the outer surface of the core of crystalline metal oxide nanoparticles. The higher specific surface area and more active sites on the surface of the amorphous metal oxide nanolayer facilitate the adsorption of reactive molecules, thereby enhancing its activity. In addition, due to the coordination unsaturation defect on the surface of the amorphous metal oxide layer, it can significantly inhibit the hydrogen evolution reaction in the electroreduction of carbon dioxide compared to ordinary crystalline metal oxides, thereby effectively improving the activity of the catalyst in the electroreduction of carbon dioxide and increasing the yield of multi-carbon products.

[0041] (2) The preparation method of the surface amorphous metal oxide nanoparticle catalyst provided by the present disclosure can form an amorphous metal oxide nano-layer on the surface of the crystalline metal oxide nanoparticle by mixing the salt template with the metal salt precursor through ball milling to obtain uniformly dispersed mixed precursors, and then calcining under a mixed atmosphere of oxygen and argon. The particle size of the crystalline metal oxide nanoparticle can be effectively controlled by controlling the ball milling time, and the crystalline metal oxide nanoparticle with smaller particle size is helpful to the formation of the surface amorphous metal oxide nano-layer. The thickness and amorphous degree of the surface amorphous metal oxide nano-layer can be controlled by controlling the oxygen content in the mixed gas during the calcination process, the calcination time, the heating rate, and the like. In addition, the method provided by the present disclosure is suitable for various metals and has strong universality.

[0042] (3) The synthesis method provided by the present disclosure is relatively simple, and the surface morphology and amorphous degree of the catalyst can be effectively controlled by controlling the ball milling mixing of the metal salt precursor and the salt template and the parameters of the high-temperature oxidation reaction, thereby providing a basis for the batch production of the catalyst. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 is a transmission electron microscope image of the surface amorphous copper oxide nanoparticle catalyst in Example 1 of the present disclosure;

[0044] Figure 2A is a high-resolution transmission electron microscope image of the surface amorphous copper oxide nanoparticle catalyst in Example 1 of the present disclosure;

[0045] Figure 2B is a scanning transmission electron microscope image of the surface amorphous copper oxide nanoparticle catalyst;

[0046] Figure 3 is a transmission electron microscope image of the crystalline copper oxide nanoparticle catalyst in Comparative Example 1 of the present disclosure;

[0047] Figure 4 is an X-ray diffraction spectrum of the surface amorphous copper oxide nanoparticle catalyst in Example 1 of the present disclosure and the crystalline copper oxide nanoparticle catalyst in Comparative Example 1 of the present disclosure;

[0048] Figure 5A is a linear scanning curve of the surface amorphous copper oxide nanoparticle catalyst in Example 1 of the present disclosure and the crystalline copper oxide nanoparticle catalyst in Comparative Example 1 of the present disclosure;

[0049] Figure 5B is a graph of the relationship between the current density and the Faraday efficiency of the surface amorphous copper oxide nanoparticle catalyst in Example 1 of the present disclosure;

[0050] Figure 6AFIG. 1 is a transmission electron microscope (TEM) image of the surface-amorphized copper oxide nanoparticle catalyst after the carbon dioxide electro-reduction reaction according to Embodiment 1 of the present disclosure;

[0051] Figure 6B FIG. 1 is a transmission electron microscope (TEM) image of the surface-amorphized copper oxide nanoparticle catalyst after the carbon dioxide electro-reduction reaction according to Embodiment 1 of the present disclosure;

[0052] Figure 7 FIG. 2 is a graph of the current density and Faraday efficiency of the surface-amorphized zinc oxide nanoparticle catalyst according to Embodiment 2 of the present disclosure;

[0053] Figure 8 FIG. 3 is a transmission electron microscope (TEM) image of the surface-amorphized zinc oxide nanoparticle catalyst according to Embodiment 5 of the present disclosure;

[0054] Figure 9A FIG. 4 is a linear sweep curve of the surface-amorphized zinc oxide nanoparticle catalyst according to Embodiment 5 of the present disclosure and the crystallized zinc oxide nanoparticle catalyst according to Comparative Example 4 of the present disclosure;

[0055] Figure 9B FIG. 5 is a graph of the current density and Faraday efficiency of the surface-amorphized zinc oxide nanoparticle catalyst according to Embodiment 5 of the present disclosure. DETAILED DESCRIPTION

[0056] In order to make the objects, technical solutions, and advantages of the present disclosure clearer, the present disclosure will be further described in detail below with specific embodiments.

[0057] In the embodiments of the present disclosure, the term "surface-amorphized" refers to the surface of a crystalline metal oxide being disordered and exhibiting a coordination unsaturation state by the action of a salt template agent.

[0058] In view of the low activity and the limitation on the selection of metal materials of the existing crystalline metal oxide in the process of carbon dioxide electrochemical reduction, and the problem that the high-efficiency reduction of carbon dioxide is accompanied by a strong hydrogen evolution side reaction under a large current density, the present disclosure proposes a surface-amorphized metal oxide nanoparticle catalyst. The surface-amorphized metal oxide nanoparticle catalyst can significantly inhibit the hydrogen evolution reaction in the carbon dioxide electro-reduction reaction while adsorbing the reaction molecules, due to the larger specific surface area, more active sites, and the presence of coordination unsaturation defects on the surface of the amorphous metal oxide nanolayer. Therefore, the surface-amorphized metal oxide nanoparticle catalyst has higher catalytic activity than the crystalline metal oxide catalyst in the carbon dioxide electro-reduction reaction.

[0059] Based on this, as a first aspect of the present disclosure, a surface amorphous metal oxide nanoparticle catalyst is provided, comprising: a crystalline metal oxide nanoparticle core; and an amorphous metal oxide nanolayer; wherein the crystalline metal oxide nanoparticle core is wrapped by the amorphous metal oxide nanolayer.

[0060] According to an embodiment of the present disclosure, the thickness of the amorphous metal oxide nanolayer is 1-10 nm, and the surface of the amorphous metal oxide nanolayer has coordination unsaturated defects; wherein the thickness of the amorphous metal oxide nanolayer can be selected as 1, 2, 5, 10 nm, etc., and more preferably 2-5 nm. Within this thickness range, the amorphous metal oxide nanolayer has a higher degree of amorphization, which can effectively retain a higher specific surface area and more active sites of the amorphous metal oxide, which is helpful for the adsorption of reaction molecules, thereby improving the carbon dioxide electroreduction activity; at the same time, the coordination unsaturated defects on the surface of the amorphous metal oxide nanolayer can effectively inhibit the hydrogen evolution reaction in the carbon dioxide electroreduction process, thereby maintaining a higher carbon dioxide electroreduction activity, wherein the coordination unsaturated defects can be coordination unsaturated of metal, or crystal planes formed by different grain boundaries.

[0061] According to an embodiment of the present disclosure, the particle size of the crystalline metal oxide nanoparticle core is 50-500 nm, wherein the particle size can be selected as 50 nm, 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, etc., and more preferably 100-200 nm.

[0062] In an embodiment of the present disclosure, the crystalline metal oxide nanoparticle core with a smaller particle size is helpful for forming an amorphous layer on the outer surface of the core, and is also helpful for the surface amorphous metal oxide nanoparticle catalyst to contact with reaction molecules.

[0063] According to an embodiment of the present disclosure, the metal oxide is a single metal oxide, a binary metal oxide, or a ternary metal oxide, or a combination thereof.

[0064] According to an embodiment of the present disclosure, the metal in the single metal oxide is selected from any one of Fe, Co, Ni, Cu, Zn, Mn, Ag, In, Sn, Ir, Pb, and Bi; the binary metal in the binary metal oxide is any one of FeCo, FeNi, CuCo, CuZn, CuSn, CuPb, InSn, and SnBi; and the ternary metal in the ternary metal oxide is any one of CuZnMn and CuZnSn.

[0065] According to an embodiment of the present disclosure, the molar ratio of the two metals in the binary metal oxide is 5:1-1:5; and the molar ratio of the three metals in the ternary metal oxide is 5:1:1-5:5:1 or 1:5:1-1:1:5.

[0066] In the embodiments of the present disclosure, the metal capable of reducing carbon dioxide is selected to prepare the surface-amorphous metal oxide nanoparticle catalyst, and by controlling the molar ratio of the metals in the binary metal oxide or ternary metal oxide, the prepared catalyst has high activity and selectivity in the process of reducing carbon dioxide, so as to generate different main products to meet the actual needs.

[0067] As a second aspect of the present disclosure, a method for preparing a surface-amorphous metal oxide nanoparticle catalyst is provided, comprising: mixing and ball-milling a metal salt precursor with a salt template to obtain a uniformly dispersed mixture precursor; placing the mixture precursor in a reactor, and performing calcination under a mixed atmosphere of argon and oxygen at a first preset temperature to obtain the surface-amorphous metal oxide nanoparticle catalyst.

[0068] Specifically, the metal salt precursor is mixed and ball-milled with the salt template to obtain a uniformly dispersed mixture precursor. Then, the mixture is placed in a reactor and subjected to calcination treatment at a first preset temperature, a heating rate and a mixed atmosphere to obtain a catalyst powder. Finally, the obtained catalyst powder is washed, centrifuged to obtain a supernatant, and dried to obtain the surface-amorphous metal oxide nanoparticle catalyst. The main mechanism of forming the catalyst is that the metal salt precursor and the salt template become a molten state when heated to a certain temperature, and the metal salt precursor becomes a crystalline metal oxide nanoparticle in the high-temperature calcination process of the molten salt template, and the molten salt makes the surface of the crystalline metal oxide become an amorphous metal oxide nanoparticle layer.

[0069] In the embodiments of the present disclosure, by effectively regulating the ball-milling mixing and high-temperature oxidation of the metal salt precursor and the salt template, a surface-amorphous metal oxide nanoparticle catalyst can be obtained.

[0070] According to the embodiments of the present disclosure, the metal salt precursor comprises at least one of the following:

[0071] Iron salt, cobalt salt, nickel salt, copper salt, zinc salt, manganese salt, silver salt, indium salt, tin salt, iridium salt, lead salt, bismuth salt.

[0072] Further, the metal salt precursor comprises at least one of the following:

[0073] acetylacetone iron (Fe(acac)3), iron nitrate nonahydrate (Fe(NO3)3·9H2O), acetylacetone cobalt (Co(acac)2), cobalt nitrate hexahydrate (Co(NO3)2·6H2O), acetylacetone nickel (Ni(acac)2), nickel nitrate hexahydrate (Ni(NO3)2·6H2O), copper hydroxide (Cu(OH)2), copper nitrate trihydrate (Cu(NO3)2·3H2O), acetylacetone copper (Cu(acac)2), acetylacetone zinc (Zn(acac)2), acetylacetone manganese (Mn(acac)2), acetylacetone silver (Ag(acac)), acetylacetone indium (In(acac)3), acetylacetone tin (Sn(acac)2), acetylacetone iridium (Ir(acac)3), acetylacetone lead (Fe(acac)3), bismuth nitrate pentahydrate (Bi(NO3)3·5H2O).

[0074] According to an embodiment of the present disclosure, the salt template is a potassium salt, and the potassium salt comprises any one of the following:

[0075] potassium bicarbonate, potassium nitrate, potassium bromide, potassium carbonate.

[0076] According to an embodiment of the present disclosure, the molar ratio of the metal salt precursor and the salt template is 5:1-25:1, which can be 5:1, 10:1, 15:1, 20:1, 25:1, etc. By controlling the molar ratio of the metal salt precursor and the salt template, the degree of amorphization can be effectively controlled, and thus the thickness of the amorphous metal oxide nanolayer can be controlled. When the molar ratio of the metal salt precursor and the salt template exceeds the range of 25:1, the amorphous metal oxide nanolayer formed can be too thick, which reduces the activity of the catalyst in the application of carbon dioxide electro-reduction. If the molar ratio of the metal salt precursor and the salt template is too low (less than 5:1), the amorphous metal oxide nanolayer cannot be effectively formed.

[0077] According to an embodiment of the present disclosure, the metal salt precursor and the salt template are mixed and ball milled to obtain a uniformly dispersed mixture precursor. The parameters of the ball milling of the mixture of the metal salt precursor and the salt template include the speed of the ball milling and the time of the ball milling. The speed of the ball milling is 200-1000 rpm, for example, 200, 400, 600, 800, 1000 rpm, etc. The time of the ball milling includes 2-20 h, for example, 2, 4, 6, 8, 10, 15, 20 h, etc., preferably 5-15 h, and more preferably 8-10 h.

[0078] In the embodiments of the present disclosure, the metal salt precursor and the salt template are put into a ball mill tank for ball milling mixing and calcination treatment at room temperature to obtain the surface amorphous metal oxide nanoparticle catalyst. By simple mechanical grinding mixing, the time of ball milling mixing and the speed of ball milling mixing are controlled to effectively adjust the particle size of the crystalline metal oxide, thereby facilitating the control of the particle size of the surface amorphous metal oxide nanoparticle catalyst. For example, at a ball milling mixing speed of 200-1000 rpm and a ball milling mixing time of 2-20 h, a crystalline metal oxide nanoparticle core with a particle size of 50 nm-500 nm can be obtained, and thus a surface amorphous metal oxide nanoparticle catalyst with a smaller particle size can be obtained. However, in the prior art, the amorphous metal oxide is generally prepared by a hot solvent method, which mainly uses a solvent to disperse the metal precursor and the salt template, and then the solvent is dried at a high temperature, and then the amorphous metal oxide is obtained by calcining in air or argon and washing away the salt template. However, this method consumes a large amount of solvent and is accompanied by solvent pollution, which is not conducive to large-scale preparation. Compared with the advantages of the ball milling method, the preparation of the metal mixture precursor by the ball milling method can realize the mass production of the amorphous metal oxide nanoparticle catalyst and reduce the preparation cost.

[0079] According to the embodiments of the present disclosure, the obtained mixed zone precursor is placed in a reactor, and calcination is carried out at a first preset temperature in a mixed atmosphere of argon and oxygen to obtain the surface amorphous metal oxide nanoparticle catalyst.

[0080] The oxygen content in the mixed gas of argon and oxygen is 5-50%, preferably 10-25%, and the flow rate of the mixed gas is 10-150 sccm. By controlling the oxygen content in the mixed gas, the thickness of the amorphous metal oxide layer can be effectively controlled. When the oxygen content is too high or too low, the amorphous metal oxide nanolayer cannot be normally formed, which affects the activity of the catalyst in the catalytic reduction reaction of carbon dioxide. Further, the oxygen content in the mixed gas is preferably 10-25%.

[0081] The temperature of the mixture precursor calcination at the first preset temperature includes 280-700℃, preferably 300-600℃, and more preferably 400-500℃. A lower calcination temperature is conducive to the formation of the amorphous metal oxide nanolayer; however, a too low calcination temperature (lower than 280℃) can easily lead to incomplete oxidation of the mixture precursor, resulting in the complete conversion of the metal into amorphous metal oxide and the inability to control the formation of crystalline metal oxide; a too high calcination temperature (higher than 700℃) can easily lead to a too fast oxidation rate, resulting in the complete conversion of the metal into crystalline metal oxide and the inability to form the amorphous metal oxide layer on the surface of the crystalline metal oxide, and thus the temperature of the mixture precursor calcination includes 280-700℃.

[0082] The calcination time of the mixture precursor at the first preset temperature of 280-700℃ includes 1-5 h, and preferably 1.5-3 h. The heating rate during calcination includes 2-20 ℃ / min, and a suitable calcination heating rate is conducive to the control of the size of the crystalline metal oxide nanoparticles. When the heating rate during calcination is too fast, the crystalline metal oxide nanoparticles can easily grow and nucleate rapidly in a short time, thereby affecting the formation of the amorphous metal oxide layer on the surface of the crystalline metal oxide and the activity of the catalyst in the catalytic process; when the heating rate during calcination is too slow, the heating time can be prolonged, which can also lead to the formation of larger crystalline metal oxide nanoparticles.

[0083] According to an embodiment of the present disclosure, after the calcination treatment, the powder after calcination is further cleaned. The specific cleaning process can be that the powder obtained by calcination is cleaned with water and ethanol for three times respectively to remove inorganic salts, and then dried in a vacuum drying box, wherein the mass fraction of ethanol used in the cleaning process is 50-99.7%, and the water used is neutral deionized water; the temperature of vacuum drying can be 40-80℃.

[0084] According to an embodiment of the present disclosure, an application of the surface-amorphized metal oxide nanoparticle catalyst is also provided, which includes: applying the surface-amorphized metal oxide nanoparticle catalyst to the electrochemical reduction of carbon dioxide to prepare a multi-carbon product; wherein the multi-carbon product includes any one of the following: ethylene, ethanol, acetic acid, and isopropanol; the surface-amorphized metal oxide nanoparticle catalyst can also be applied to the electrochemical reduction of carbon dioxide to prepare a one-carbon product; wherein the one-carbon product includes any one of the following: carbon monoxide, methane, and formic acid.

[0085] The technical solutions of the present disclosure are further described and explained below by specific embodiments in conjunction with the accompanying drawings. It should be noted that the specific embodiments described below are only illustrative, and the protection scope of the present disclosure is not limited thereto. The chemical drugs and raw materials used in the following embodiments are obtained from the market or self-made by a recognized preparation method.

[0086] Example 1

[0087] The present example 1 provides a method for preparing a surface amorphous copper-based catalyst, the specific steps are as follows:

[0088] 1) : 1.91 mmol Cu(acac)2, 27 mmol KHCO3 were mixed and added into a ball mill tank, and the mixture was ball milled at a speed of 400 rpm for 10 h to obtain a copper-based mixture precursor;

[0089] 2) : The copper-based mixture precursor prepared in 1) was placed in a reaction furnace and calcined under an Ar / O2 mixed atmosphere with a flow rate of 50 sccm and an O2 content of 20%, the heating rate during calcination was 5 ℃ / min, the calcination temperature was 500 ℃, and the calcination time was 2 h, to obtain a brown powder.

[0090] 3) : The brown powder obtained in 2) was placed in a 50 ml centrifuge tube, 40 ml of water was added and ultrasonic treatment was performed for 10 min, then centrifugation was performed at a speed of 11000 rpm for 2 min, and then the powder was washed with water and ethanol for three times respectively and centrifuged under the same conditions. Then, the powder was dried in a vacuum drying oven at 70 ℃ for 12 h to obtain a black powder, which is a surface amorphous copper oxide nanoparticle catalyst, named as a-CuO@c-CuO-ac catalyst 1.

[0091] Using the method in example 1, the average diameter of CuO particles in the obtained surface amorphous copper oxide nanoparticle catalyst is about 100 nm, and the thickness of the surface amorphous copper oxide nanolayer is about 2 nm.

[0092] Figure 1 is a transmission electron microscope (TEM) image of the surface amorphous copper oxide nanoparticle catalyst in example 1 of the present disclosure.

[0093] As shown in Figure 1 , it can be seen from the figure that the particle size of the surface amorphous copper oxide nanoparticle catalyst is about 150 nm.

[0094] Figure 2A is a high-resolution transmission electron microscope (HRTEM) image of the surface amorphous copper oxide nanoparticle catalyst in example 1 of the present disclosure; Figure 2B is a scanning transmission electron microscope (STEM) image of the surface amorphous copper oxide nanoparticle catalyst.

[0095] As can be seen from Figures 2A-2B , there is a layer of amorphous copper oxide nanolayer with a thickness of about 2 nm on the surface of the surface amorphous copper oxide nanoparticle.

[0096] Comparative Example 1

[0097] The preparation method of the crystallized copper oxide nanoparticle catalyst in Comparative Example 1 is the same as that in Example 1, the only difference is that KHCO3 is not added, and Cu(acac)2 is directly calcined under the same conditions to obtain a crystallized copper oxide nanoparticle catalyst, which is named as c-CuO-ac.

[0098] Figure 3 is a transmission electron microscope (TEM) image of the crystallized copper oxide nanoparticle catalyst in Comparative Example 1 of the present disclosure.

[0099] As shown in Figure 3 , it can be seen from the figure that the particle size of the crystallized copper oxide nanoparticle catalyst is about 500 nm.

[0100] Figure 4 is an X-ray diffraction spectrum of the surface amorphous copper oxide nanoparticle catalyst in Example 1 of the present disclosure and the crystallized copper oxide nanoparticle catalyst in Comparative Example 1.

[0101] As shown in Figure 4 , the peak height of the surface amorphous copper oxide nanoparticle catalyst is slightly lower than that of the crystallized copper oxide nanoparticle catalyst, which also indicates the decrease of its crystallinity.

[0102] Figure 5A is a linear sweep curve (LSV) of the surface amorphous copper oxide nanoparticle catalyst in Example 1 of the present disclosure and the crystallized copper oxide nanoparticle catalyst in Comparative Example 1.

[0103] As shown in Figure 5A , under the same voltage, the surface amorphous copper oxide nanoparticle catalyst (Example 1) has a higher current density than the crystallized copper oxide nanoparticle catalyst (Comparative Example 1), which indicates that the surface amorphous copper oxide nanoparticle catalyst has better carbon dioxide electroreduction performance. Among them, Figure 5A The instrument used for testing is an electrochemical workstation produced by Shanghai Chenhua Company, model CHI1140c.

[0104] Figure 5B is a graph of the relationship between current density and faradic efficiency of the surface amorphous copper oxide nanoparticle catalyst in Example 1 of the present disclosure.

[0105] In the flow cell, 1M KOH is used as the anode and cathode electrolyte, the gas diffusion electrode with a flow rate of 40 ml / min is used as the cathode working electrode, the foamed nickel is used as the anode counter electrode, CO2 is passed into the flow cell at a flow rate of 60 ml / min, and the reaction is carried out under the condition of power supply. The faradic efficiency of the carbon dioxide electroreduction catalyzed by the catalysts of Examples and Comparative Example 1 is measured by using the constant current method. As shown in Figure 5B , the highest current density of the surface amorphous copper oxide nanoparticle catalyst (Example 1) is 2 A·cm 2at the same time, the faradaic efficiency of the multi-carbon product (C 2+ is above 80%.

[0106] Figure 6A is a transmission electron microscope (TEM) image of the surface amorphous copper oxide nanoparticle catalyst in Example 1 of the present disclosure after the carbon dioxide electroreduction reaction. Figure 6B is a transmission electron microscope (TEM) image of the crystallized copper oxide nanoparticle catalyst in Comparative Example 1 of the present disclosure after the carbon dioxide electroreduction reaction.

[0107] As shown in FIG. 1, the copper oxide in the catalysts in Example 1 and Comparative Example 1 is reduced to Cu after the carbon dioxide electroreduction reaction, and compared with the crystallized copper oxide particle catalyst in Comparative Example 1, the Cu in Example 1 has higher roughness and surface defects, indicating that it is likely to be a source of higher activity. Figures 6A-6B

[0108] Example 2

[0109] The present Example 2 provides a preparation method of a surface amorphous copper-based catalyst, and the specific steps are as follows:

[0110] 1) : 1.91 mmol Cu(acac)2, 13.5 mmol KHCO3 were mixed and added to a ball mill tank, and ball milling was carried out at a rotation speed of 400 rpm for 10 h to obtain a copper-based mixture precursor;

[0111] 2) : The copper-based mixture precursor prepared in 1) was placed in a reaction furnace and calcined under an Ar / O2 atmosphere with a flow rate of 50 sccm and an O2 content of 20%, the heating rate during calcination was 5 ℃ / min, the calcination temperature was 500 ℃, and the calcination time was 2 h, to obtain a brown powder.

[0112] 3) : The brown powder obtained in 2) was placed in a 50 ml centrifuge tube, 40 ml of water was added and ultrasonic treatment was carried out for 10 min, then centrifugation was carried out at a rotation speed of 11000 rpm for 2 min, and then the powder was washed with water and ethanol for three times respectively and centrifuged under the same conditions, and then dried in a vacuum drying oven at 70 ℃ for 12 h to obtain a black powder, which is a surface amorphous copper oxide nanoparticle catalyst, named as a-CuO@c-CuO-ac catalyst 2.

[0113] Figure 7 is a graph of the relationship between the current density and the faradaic efficiency of the surface amorphous copper oxide nanoparticle catalyst in Example 2 of the present disclosure.

[0114] ​The specific test process is: in a flow cell, 1M KOH is used as the anode and cathode electrolyte, a gas diffusion electrode with a flow rate of 40 ml / min is used as the cathode working electrode, and foamed nickel is used as the anode counter electrode. CO2 is passed into the flow cell at a flow rate of 60 ml / min and reacts under the condition of power supply. The Faraday efficiency of the catalyst of Example 2 for the electroreduction of carbon dioxide is measured by using a constant current method. The measured results are shown in Table 1. Figure 7 As shown in Table 1, when the maximum current density is 0.6 A·cm -2 , the Faraday efficiency of the multi-carbon product (C 2+ ) is more than 70%.

[0115] Example 3

[0116] This Example 3 provides a preparation method of a surface amorphous iron-based catalyst, and the specific steps are as follows:

[0117] 1) : 1.91 mmol Fe(acac)3, 27 mmol KHCO3 are mixed and added into a ball mill tank, and ball milling is carried out at a rotation speed of 200 rpm for 10 h to obtain an iron-based mixture precursor;

[0118] 2) : The iron-based mixture precursor prepared in 1) is placed in a reaction furnace and calcined under an Ar / O2 atmosphere with a flow rate of 20 sccm and an O2 content of 25%, the heating rate during calcination is 10 ℃ / min, the calcination temperature is 300 ℃, and the calcination time is 2 h, to obtain a black powder.

[0119] 3) : The black powder in 2) is placed in a 50 ml centrifuge tube, 40 ml of water is added and ultrasonic treatment is carried out for 10 min, then centrifugation is carried out at a rotation speed of 11000 rpm for 2 min, then the powder is washed with water and ethanol for three times respectively and centrifuged under the same conditions, and then dried in a vacuum drying oven at 70 ℃ for 12 h to obtain a black powder, which is a surface amorphous iron oxide nanoparticle catalyst, named as a-Fe2O3@c-Fe2O3-ac catalyst 3.

[0120] The average diameter of Fe2O3 particles in the surface amorphous iron oxide nanoparticle catalyst obtained by the method in Example 3 is about 200 nm, and the thickness of the surface amorphous iron oxide nanolayer is about 5 nm.

[0121] Comparative Example 2

[0122] The preparation method of the crystallized iron oxide nanoparticle catalyst in Comparative Example 2 is the same as that in Example 3, the only difference is that KHCO3 is not added, and Fe(acac)3 is directly calcined under the same conditions to obtain a crystallized iron oxide nanoparticle catalyst, named as c-Fe2O3-ac.

[0123] Example 4

[0124] The embodiment 4 provides a preparation method of a surface amorphous cobalt-based catalyst, and the specific steps are as follows:

[0125] 1): 2 mmol Co (acac) 2, 27 mmol KHCO 3 were mixed and added into a ball mill tank, and ball milling was carried out at a rotating speed of 600 rpm for 10 h to obtain a cobalt-based mixture precursor;

[0126] 2): the cobalt-based mixture precursor prepared in 1) was placed in a reaction furnace and calcined under an Ar / O 2 atmosphere with a flow rate of 40 sccm and an O 2 content of 10%, the temperature rising rate in the calcination process was 15 ℃ / min, the calcination temperature was 600 ℃, and the calcination time was 2 h, to obtain a black powder.

[0127] 3): the black powder obtained in 2) was placed into a 50 ml centrifuge tube, 40 ml of water was added and ultrasonic treatment was carried out for 10 min, then centrifugation was carried out at a rotating speed of 11000 rpm for 2 min, and then the black powder was obtained by washing with water and ethanol for three times and centrifugation under the same conditions, namely a surface amorphous cobalt oxide nanoparticle catalyst, named as a-CoO@c-CoO-ac catalyst 4.

[0128] The average diameter of the CoO particles in the surface amorphous cobalt oxide nanoparticle catalyst obtained by the method in the embodiment 4 is about 50 nm, and the thickness of the surface amorphous cobalt oxide nanolayer is about 1 nm.

[0129] Comparative example 3

[0130] The preparation method of the crystallized cobalt oxide nanoparticle catalyst in the comparative example 3 is the same as that in the embodiment 4, and the only difference is that no KHCO 3 is added, and the calcination is directly carried out under the same conditions, to obtain a crystallized cobalt oxide nanoparticle catalyst, named as c-CoO-ac.

[0131] Embodiment 5

[0132] The embodiment 5 provides a preparation method of a surface amorphous zinc-based catalyst, and the specific steps are as follows:

[0133] 1): 1.91 mmol Zn (acac) 2, 27 mmol KHCO 3 were mixed and added into a ball mill tank, and ball milling was carried out at a rotating speed of 500 rpm for 10 h to obtain a zinc-based mixture precursor;

[0134] 2): the zinc-based mixture precursor prepared in 1) was placed in a reaction furnace and calcined under an Ar / O 2 atmosphere with a flow rate of 20 sccm and an O 2 content of 25%, the temperature rising rate in the calcination process was 10 ℃ / min, the calcination temperature was 600 ℃, and the calcination time was 2 h, to obtain a white powder.

[0135] 3): The white powder obtained in 2) was placed in a 50 ml centrifuge tube, 40 ml water was added and ultrasonic treatment was performed for 10 min, then centrifugation was performed at a speed of 11000 rpm for 2 min, and then washing was performed with water and ethanol each for three times and centrifugation was performed under the same conditions, and then drying was performed in a vacuum drying oven at 70°C for 12 h to obtain a white powder, which was a surface amorphous zinc oxide nanoparticle catalyst, named as a-ZnO@c-ZnO-ac catalyst 5.

[0136] The average diameter of the ZnO particles in the surface amorphous zinc oxide nanoparticle catalyst obtained in the method of Example 5 was about 150 nm, and the thickness of the surface amorphous zinc oxide nanolayer was about 3 nm.

[0137] Comparative Example 4

[0138] The preparation method of the crystalline zinc oxide nanoparticle catalyst in Comparative Example 4 was the same as that in Example 5, and the only difference was that KHCO3 was not added, and Zn(acac)2 was directly calcined under the same conditions to obtain a crystalline zinc oxide nanoparticle catalyst, named as c-ZnO-ac.

[0139] Figure 8 is a transmission electron microscope (TEM) image of the surface amorphous zinc oxide nanoparticle catalyst in Example 5 of the present disclosure.

[0140] As shown in Figure 8 , it can be seen from the figure that the thickness of the amorphous ZnO nanolayer of the surface amorphous zinc oxide nanoparticle catalyst is about 3 nm.

[0141] Figure 9A is a linear sweep curve (LSV) image of the surface amorphous zinc oxide nanoparticle catalyst in Example 5 of the present disclosure and the crystalline zinc oxide nanoparticle catalyst in Comparative Example 4.

[0142] As shown in Figure 9A , under the same voltage, the surface amorphous zinc oxide nanoparticle catalyst (Example 5) has a higher current density than the crystalline zinc oxide nanoparticle catalyst (Comparative Example 4), indicating that the carbon dioxide electro-reduction performance of the surface amorphous zinc oxide nanoparticle catalyst is better, wherein, Figure 9A The instrument used for testing was an electrochemical workstation produced by Shanghai Chenhua Company, model CHI1140c.

[0143] Figure 9B is a graph of the relationship between the current density and the Faraday efficiency of the surface amorphous zinc oxide nanoparticle catalyst in Example 5 of the present disclosure.

[0144] The specific test process is: in a flow cell, 1 M KOH is used as the anode and cathode electrolyte, a gas diffusion electrode with a flow rate of 40 ml / min is used as the cathode working electrode, foamed nickel is used as the anode counter electrode, CO2 is passed into the flow cell at a flow rate of 60 ml / min, and the reaction is carried out under the condition of power supply. The Faraday efficiency of the catalysts of the examples and Comparative Example 1 for the electroreduction of carbon dioxide is measured by using a constant current method. The measured test results are shown in Table 1. Figure 9B As shown in Table 1, the maximum current density is 1.2 A·cm 2 and the Faraday efficiency of the CO product is more than 99 %.

[0145] Example 6

[0146] This Example 6 provides a preparation method of a surface amorphous silver catalyst, and the specific steps are as follows:

[0147] 1) : 1.91 mmol of Ag(acac) and 44 mmol of KHCO3 are mixed and added into a ball mill tank, and ball milling is carried out at a rotation speed of 400 rpm for 10 h to obtain a silver mixture precursor;

[0148] 2) : The silver mixture precursor prepared in 1) is placed in a reaction furnace and calcined under an Ar / O2 atmosphere with a flow rate of 30 sccm and an O2 content of 40%, the temperature rising rate during calcination is 20 ℃ / min, the calcination temperature is 600 ℃, and the calcination time is 2 h, to obtain a gray powder.

[0149] 3) : The gray powder obtained in 2) is placed into a 50 ml centrifuge tube, 40 ml of water is added and ultrasonic treatment is carried out for 10 min, then centrifugation is carried out at a rotation speed of 11000 rpm for 2 min, and then the powder is washed with water and ethanol each for three times and centrifuged under the same conditions, and then dried in a vacuum drying oven at 70 ℃ for 12 h, to obtain a silver gray luster powder, which is a surface amorphous silver nanoparticle catalyst, and is named as a-Ag@c-Ag-ac catalyst 6.

[0150] The average diameter of the Ag particles in the surface amorphous silver nanoparticle catalyst obtained by the method in Example 6 is about 500 nm, and the thickness of the surface amorphous silver nanolayer is about 10 nm.

[0151] Comparative Example 5

[0152] The preparation method of the crystallized silver oxide nanoparticle catalyst in Comparative Example 5 is the same as that in Example 6, and the only difference is that KHCO3 is not added, and Ag(acac) is directly calcined under the same conditions to obtain a crystallized silver oxide nanoparticle catalyst, which is named as c-Ag-ac.

[0153] Example 7

[0154] The embodiment 7 provides a preparation method of a surface amorphous manganese-based catalyst, and the specific steps are as follows:

[0155] 1): 1.91 mmol of Mn(acac)2 and 27 mmol of KHCO3 are mixed and added into a ball mill tank, and ball milling is performed at a rotating speed of 800 rpm for 10 h to obtain a manganese-based mixture precursor;

[0156] 2): the manganese-based mixture precursor prepared in 1) is placed in a reaction furnace and calcined under an Ar / O2 atmosphere with a flow rate of 30 sccm and an O2 content of 40%, the temperature rising rate in the calcination process is 20 ℃ / min, the calcination temperature is 600 ℃, and the calcination time is 2 h, to obtain a gray powder.

[0157] 3): the gray powder obtained in 2) is placed into a 50 ml centrifuge tube, 40 ml of water is added and ultrasonic treatment is performed for 10 min, then centrifugation is performed at a rotating speed of 11000 rpm for 2 min, and then the powder is washed with water and ethanol for three times respectively and centrifuged under the same conditions, and the powder is dried in a vacuum drying box at 70 ℃ for 12 h, to obtain a black powder, which is a surface amorphous manganese oxide nanoparticle catalyst, and is named as a-MnO@c-MnO-ac catalyst 7.

[0158] The average diameter of the MnO particles in the surface amorphous manganese oxide nanoparticle catalyst prepared by the method in the embodiment 7 is about 80 nm, and the thickness of the surface amorphous manganese oxide nanolayer is about 8 nm.

[0159] Comparative example 6

[0160] The preparation method of the crystallized manganese oxide nanoparticle catalyst in the comparative example 6 is the same as that in the embodiment 7, and the only difference is that KHCO3 is not added, and the crystallized manganese oxide nanoparticle catalyst is obtained by directly calcining Mn(acac)3 under the same conditions, and is named as c-MnO-ac.

[0161] Embodiment 8

[0162] The embodiment 8 provides a preparation method of a surface amorphous indium-based catalyst, and the specific steps are as follows:

[0163] 1): 1.91 mmol of In(acac)3 and 14 mmol of KHCO3 are mixed and added into a ball mill tank, and ball milling is performed at a rotating speed of 400 rpm for 10 h to obtain an indium-based mixture precursor;

[0164] 2): the indium-based mixture precursor prepared in 1) is placed in a reaction furnace and calcined under an Ar / O2 atmosphere with a flow rate of 20 sccm and an O2 content of 25%, the temperature rising rate in the calcination process is 10 ℃ / min, the calcination temperature is 300 ℃, and the calcination time is 2 h, to obtain a light yellow powder.

[0165] 3): The yellowish powder obtained in 2) was placed in a 50 ml centrifuge tube, 40 ml water was added and ultrasonic treatment was performed for 10 min, then centrifugation was performed at a speed of 11000 rpm for 2 min, and then washing was performed with water and ethanol each for three times and centrifugation was performed under the same conditions, and then drying was performed in a vacuum drying oven at 70°C for 12 h, to obtain a yellowish powder, which was a surface amorphous indium oxide nanoparticle catalyst, named as a-In2O3@c-In2O3-ac catalyst 8.

[0166] The average diameter of the In2O3 particles in the surface amorphous indium oxide nanoparticle catalyst prepared by the method in Example 8 was about 200 nm, and the thickness of the surface amorphous indium oxide nanolayer was about 6 nm.

[0167] Comparative Example 7

[0168] The preparation method of the crystalline indium oxide nanoparticle catalyst in Comparative Example 7 was the same as that in Example 8, except that KHCO3 was not added, and Cu(acac)2 was directly calcined under the same conditions, to obtain a crystalline indium oxide nanoparticle catalyst, named as c-In2O3-ac.

[0169] Example 9

[0170] This Example 9 provides a preparation method of a surface amorphous tin-based catalyst, and the specific steps are as follows:

[0171] 1): 1.91 mmol Sn(acac)2, 14 mmol KHCO3 were mixed and added into a ball mill tank, and ball milling was performed at a speed of 200 rpm for 10 h, to obtain a tin-based mixture precursor;

[0172] 2): The tin-based mixture precursor prepared in 1) was placed in a reaction furnace, and calcination was performed under an Ar / O2 atmosphere with a flow rate of 20 sccm and an O2 content of 25%, the temperature rising rate during calcination was 10°C / min, the calcination temperature was 300°C, and the calcination time was 2 h, to obtain a white powder.

[0173] 3): The white powder obtained in 2) was placed in a 50 ml centrifuge tube, 40 ml water was added and ultrasonic treatment was performed for 10 min, then centrifugation was performed at a speed of 11000 rpm for 2 min, and then washing was performed with water and ethanol each for three times and centrifugation was performed under the same conditions, and then drying was performed in a vacuum drying oven at 70°C for 12 h, to obtain a white powder, which was a surface amorphous tin oxide nanoparticle catalyst, named as a-SnO2@c-SnO2-NO3 catalyst 9.

[0174] The Sn02particles in the surface amorphous tin oxide nanoparticle catalyst prepared by the method in Example 9 have an average diameter of about 300 nm, and the surface amorphous tin oxide nanolayer has a thickness of about 8 nm.

[0175] Comparative Example 8

[0176] The preparation method of the crystallized tin oxide nanoparticle catalyst in Comparative Example 8 is the same as that in Example 9, except that KHCO3 is not added, and Sn(acac)2 is directly calcined under the same conditions to obtain a crystallized tin oxide nanoparticle catalyst, which is named c-Sn02-ac.

[0177] Example 10

[0178] This Example 10 provides a preparation method of a surface amorphous bismuth-based catalyst, and the specific steps are as follows:

[0179] 1) : 1.91 mmol of Bi(NO3)3·5H2O and 44 mmol of KHCO3 were mixed and added to a ball mill tank, and ball milling was performed at a rotation speed of 400 rpm for 10 h to obtain a bismuth-based mixture precursor;

[0180] 2) : The bismuth-based mixture precursor prepared in 1) was placed in a reaction furnace and calcined under an Ar / O2 atmosphere with a flow rate of 30 sccm and an O2 content of 40%, the temperature rising rate during calcination was 20℃ / min, the calcination temperature was 600℃, and the calcination time was 2 h, to obtain a light yellow powder.

[0181] 3) : The light yellow powder obtained in 2) was placed in a 50 ml centrifuge tube, 40 ml of water was added and ultrasonic treatment was performed for 10 min, then centrifugation was performed at a rotation speed of 11000 rpm for 2 min, and then the powder was washed with water and ethanol each for three times and centrifuged under the same conditions, and then dried in a vacuum drying oven at 70℃ for 12 h to obtain a yellow powder, which is a surface amorphous bismuth oxide nanoparticle catalyst, and is named a-Bi2O3@c-Bi2O3-NO3 catalyst 10.

[0182] The Bi2O3particles in the surface amorphous bismuth oxide nanoparticle catalyst prepared by the method in Example 10 have an average diameter of about 500 nm, and the surface amorphous bismuth oxide nanolayer has a thickness of about 4 nm.

[0183] Comparative Example 9

[0184] The preparation method of the crystallized bismuth oxide nanoparticle catalyst in Comparative Example 9 is the same as that in Example 10, except that KHCO3 is not added, and Bi(NO3)3·5H2O is directly calcined under the same conditions to obtain a crystallized bismuth oxide nanoparticle catalyst, which is named c-Bi2O3-NO3.

[0185] Example 11

[0186] This example 11 provides a method for preparing a surface amorphous copper-zinc-based catalyst, and the specific steps are as follows:

[0187] 1) : 1.91 mmol Cu(acac)2, 1.91 mmol Zn(acac)2 and 44 mmol KHCO3 were mixed and added to a ball mill tank, and ball milling was carried out at a rotation speed of 800 rpm for 10 h to obtain a copper-zinc-based mixture precursor;

[0188] 2) : The copper-zinc-based mixture precursor prepared in 1) was placed in a reaction furnace and calcined under an Ar / O2 atmosphere with a flow rate of 40 sccm and an O2 content of 30%, the temperature rising rate during calcination was 10 ℃ / min, the calcination temperature was 500 ℃, and the calcination time was 2 h, to obtain a gray powder.

[0189] 3) : The gray powder obtained in 2) was placed in a 50 ml centrifuge tube, 40 ml of water was added and ultrasonic treatment was carried out for 10 min, then centrifugation was carried out at a rotation speed of 11000 rpm for 2 min, and then the powder was washed with water and ethanol for three times respectively and centrifuged under the same conditions, and then dried in a vacuum drying oven at 70 ℃ for 12 h, to obtain a black powder, which was a surface amorphous copper oxide / zinc oxide heteronanoparticle catalyst, named as a-CuO / ZnO@c-CuO / ZnO-ac catalyst 11.

[0190] The average diameter of CuO / ZnO particles in the amorphous copper oxide / zinc oxide heteronanoparticle catalyst prepared by the method in example 11 was about 100 nm, and the thickness of the surface amorphous copper oxide / zinc oxide heteronanoparticle layer was about 2 nm.

[0191] Comparative Example 10

[0192] The preparation method of the crystalline copper oxide / zinc oxide heteronanoparticle catalyst in comparative example 10 was the same as that in example 11, the only difference was that KHCO3 was not added, and Cu(acac)2 was directly calcined under the same conditions, to obtain a crystalline copper oxide / zinc oxide heteronanoparticle catalyst, named as c-CuO / ZnO.

[0193] Example 12

[0194] This example 12 provides a method for preparing a surface amorphous copper-zinc-tin-based catalyst, and the specific steps are as follows:

[0195] 1): 1.91 mmol Cu(acac)2, 1.91 mmol Zn(acac)2, 1.91 mmol Sn(acac)2 and 5 mmol KHCO3 were mixed and added into a ball mill tank, and ball milling was carried out at a rotation speed of 800 rpm for 10 h to obtain a copper-zinc-tin-based mixture precursor;

[0196] 2): The copper-zinc-tin-based mixture precursor prepared in 1) was placed in a reaction furnace and calcined under an Ar / O2 atmosphere with a flow rate of 40 sccm and an O2 content of 30%, the temperature was raised at a rate of 10 ℃ / min during the calcination process, the calcination temperature was 400 ℃, and the calcination time was 2 h, to obtain a black powder.

[0197] 3): The black powder obtained in 2) was placed in a 50 ml centrifuge tube, 40 ml of water was added and ultrasonic treatment was carried out for 10 min, then centrifugation was carried out at a rotation speed of 11000 rpm for 2 min, and then the powder was washed with water and ethanol each for three times and centrifuged under the same conditions, and then dried in a vacuum drying oven at 70 ℃ for 12 h to obtain a black powder, which was a surface amorphous copper / zinc / tin oxide hetero-nanoparticle catalyst, named as a-CuO / ZnO / SnO2@c-CuO / ZnO / SnO2-ac catalyst 12.

[0198] The average diameter of the CuO / ZnO / SnO2 particles in the surface amorphous copper / zinc / tin oxide hetero-nanoparticle catalyst prepared by the method in Example 12 was about 100 nm, and the thickness of the surface amorphous copper / zinc / tin oxide hetero-nanoparticle layer was about 2 nm.

[0199] Comparative Example 11

[0200] The preparation method of the crystalline copper / zinc / tin oxide hetero-nanoparticle catalyst in Comparative Example 11 was the same as that in Example 12, the only difference was that KHCO3 was not added, and the Cu(acac)2 / Zn(acac)2 / Sn(acac)2 was directly calcined under the same conditions to obtain a crystalline copper / zinc / tin oxide hetero-nanoparticle catalyst, named as c-CuO / ZnO / SnO2.

[0201] The above specific examples further illustrate the purpose, technical solutions and beneficial effects of the present disclosure, and it should be understood that the above examples are only specific embodiments of the present disclosure and are not intended to limit the present disclosure. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present disclosure shall be included in the protection scope of the present disclosure.

Claims

1. A method for preparing a surface amorphous metal oxide nanoparticle catalyst, comprising: ball-milling a metal salt precursor and a salt template to obtain a uniformly dispersed mixture precursor; placing the mixture precursor in a reactor, and performing calcination under a mixed atmosphere of argon and oxygen at a first preset temperature to obtain a surface amorphous metal oxide nanoparticle catalyst; wherein the surface amorphous metal oxide nanoparticle catalyst comprises: a crystalline metal oxide nanoparticle core, and an amorphous metal oxide nanolayer; the crystalline metal oxide nanoparticle core is wrapped by the amorphous metal oxide nanolayer; wherein the molar ratio of the metal salt precursor to the salt template is 5:1-25:1; the oxygen content in the mixed gas of argon and oxygen is 5-50%, and the flow rate of the mixed gas is 10-150 sccm; the first preset temperature range comprises 280-700℃; wherein the thickness of the amorphous metal oxide nanolayer is 1-10 nm, and there are coordination unsaturated defects on the surface; the particle size of the crystalline metal oxide nanoparticle core is 50-500 nm; the metal salt precursor comprises at least one of: iron salt, cobalt salt, nickel salt, copper salt, zinc salt, manganese salt, silver salt, indium salt, tin salt, iridium salt, lead salt, bismuth salt; the salt template is potassium salt.

2. The method of claim 1, wherein, the metal oxide is a single metal oxide, a binary metal oxide or a ternary metal oxide, or a combination thereof, wherein the metal in the single metal oxide is selected from any one of Fe, Co, Ni, Cu, Zn, Mn, Ag, In, Sn, Ir, Pb, Bi; the binary metal in the binary metal oxide is any one of FeCo, FeNi, CuCo, CuZn, CuSn, CuPb, InSn, SnBi; the ternary metal in the ternary metal oxide is any one of CuZnMn, CuZnSn.

3. The method of claim 2, wherein, the molar ratio of the two metals in the binary metal oxide is 5:1-1:5; the molar ratio of the three metals in the ternary metal oxide is 5:1:1-5:5:1 or 1:5:1-1:1:

5.

4. The method of claim 1, wherein, the potassium salt comprises any one of: potassium bicarbonate, potassium nitrate, potassium bromide, potassium carbonate.

5. The method of claim 1, wherein, the metal salt precursor comprises at least one of: iron acetylacetonate, iron nitrate nonahydrate, cobalt acetylacetonate, cobalt nitrate hexahydrate, nickel acetylacetonate, nickel nitrate hexahydrate, copper hydroxide, copper nitrate trihydrate, copper acetylacetonate, zinc acetylacetonate, manganese acetylacetonate, silver acetylacetonate, indium acetylacetonate, tin acetylacetonate, iridium acetylacetonate, lead acetylacetonate, bismuth nitrate pentahydrate.

6. The method of claim 5, wherein, the parameters for ball-milling the mixture of the metal salt precursor and the salt template comprise: the speed of the ball-milling is 200-1000 rpm; the time of the ball-milling comprises 2-20 h.

7. The method of claim 1, wherein the parameters for performing calcination at the first preset temperature comprise: the heating rate of the calcination comprises 2-20 ℃ / min; the time of the calcination comprises 1-5 h.

8. Use of the surface amorphized metal oxide nanoparticle catalyst prepared by the method of any one of claims 1-7, comprising: applying the surface amorphized metal oxide nanoparticle catalyst to electrochemical reduction of carbon dioxide to produce a multi-carbon product; wherein the multi-carbon product comprises any one of: ethylene, ethanol, acetic acid, isopropanol.

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