Hydrotalcite-derived copper-based nano-catalyst for preparing methanol through CO / CO2 hydrogenation as well as preparation method and application of hydrotalcite-derived copper-based nano-catalyst

Abstract

The invention provides a hydrotalcite-derived copper-based nano-catalyst as well as a preparation method and application thereof. The hydrotalcite-derived copper-based nano-catalyst provided by the invention can effectively improve the yield of methanol in a CO and / or CO2 hydrogenation reaction process and keep excellent activity and selectivity of the catalyst. According to the present invention, the characteristic that the active metal component prepared after the structure topology transformation is highly dispersed and still maintains the intercalation structure is utilized by using the characteristic that the metal element composition ratio of the hydrotalcite is adjustable and the parameters of the structure topology transformation process are controllable, such that the microstructure regulation of Cu in the Cu-based nano-catalyst is achieved. The Cu-based nano-catalyst prepared by the method is good in Cu dispersity, the geometric structure and electronic characteristics of a metal-carrier interface can be regulated and controlled, and when the Cu-based nano-catalyst is used for CO / CO2 hydrogenation reaction, the Cu-based nano-catalyst shows excellent catalytic reaction performance and can be popularized and applied to various heterogeneous catalytic reaction fields such as hydrogenation and dehydrogenation.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogenation catalysts, and relates to a hydrotalcite-derived copper-based nanocatalyst and a preparation method and application thereof, and in particular to a hydrotalcite-derived copper-based nanocatalyst for CO / CO2 hydrogenation to methanol and a preparation method and application thereof. Background Art

[0002] With the development and utilization of fossil energy such as coal, oil, and natural gas, the concentration of carbon dioxide in the atmosphere continues to rise, causing increasingly serious climate problems such as global warming and sea level rise, as well as environmental pollution. Combined with the current needs and background of environmental protection, the hydrogenation of the main greenhouse gas CO2 into high-value chemicals such as methanol can not only alleviate the increasingly serious environmental problems, but also make CO2 a resource and energy utilization to reduce people's dependence on fossil fuels. It is a carbon resource utilization route with development prospects. Among the many catalytic conversion pathways, using CO / CO2 as a carbon source to react with hydrogen to produce high-value-added chemicals can effectively reduce carbon emissions and other problems, and can also obtain usable energy and resources. Methanol, as one of the products of the reaction, is not only widely used as one of the most important chemical raw materials in the chemical, pesticide, pharmaceutical, building materials, automotive and other industries; it can also be used as fuel, fuel additives to increase octane number, and energy storage materials. It is a clean energy with good development prospects. Therefore, using hydrogen sources such as "green hydrogen" to catalytically hydrogenate CO / CO2 into methanol at a certain temperature and pressure is a CCUS technology with both industrial application and academic research value.

[0003] At present, one of the keys to the thermal catalytic hydrogenation of CO / CO2 to methanol is the development of high-performance hydrogenation catalysts. The main active components include non-precious metal catalysts represented by Cu and Co and precious metal catalysts represented by Pd and Rh. Among them, Cu-based catalysts have excellent H2 dissociation activation ability and relatively mild hydrogenation ability, and can also avoid the formation of byproducts such as CH4 by complete hydrogenation. At the same time, they are cheap and easy to obtain. From the perspective of reaction thermodynamics, since the CO / CO2 hydrogenation to methanol reaction is an exothermic reaction with a reduced number of molecules, it is suitable to be carried out at lower temperatures and high pressures. However, CO2 is an inert molecule and is difficult to activate at low temperatures. Therefore, the low-temperature single-pass CO2 conversion rate of Cu-based catalysts is low, and side reactions are prone to occur at high temperatures. In addition to methanol, some water is generated as the main product during the reaction. Together with the high temperature, this causes the Cu active components in the Cu-based catalyst to undergo hydrothermal sintering, migrate and agglomerate into large-sized particles, which seriously affects its performance.

[0004] Therefore, how to improve the activity, selectivity and stability of catalysts and overcome the above-mentioned defects has become one of the focuses of attention of many forward-looking researchers in the industry. Summary of the invention

[0005] In view of this, the technical problem to be solved by the present invention is to provide a hydrotalcite-derived copper-based nanocatalyst and its preparation method and application, in particular, a hydrotalcite-derived copper-based nanocatalyst for CO / CO2 (CO and / or CO2) hydrogenation to methanol. The hydrotalcite-derived copper-based nanocatalyst provided by the present invention has good Cu dispersibility, improves the hydrogenation active sites on the Cu surface, and the geometric structure and electronic properties of the metal-carrier interface in the catalyst are controllable, has strong metal-carrier interaction, and has high catalytic performance when used for CO / CO2 hydrogenation reaction, and is more conducive to industrial production and popularization and application.

[0006] The present invention provides a hydrotalcite-derived copper-based nanocatalyst, wherein the hydrotalcite-derived copper-based nanocatalyst is obtained by subjecting a multi-metal hydroxide precursor having a hydrotalcite intercalation structure to a structural topological transformation treatment;

[0007] The metal includes Cu, Zn and Al;

[0008] The hydrotalcite-derived copper-based nanocatalyst has a nano-level layered structure.

[0009] Preferably, in the copper-based catalyst, the molar ratio of Cu to Zn is (0.1-10): (0.1-10);

[0010] In the copper-based catalyst, the molar ratio of the total molar number of Cu+Zn to Al is (1-6):1;

[0011] The hydrotalcite-derived copper-based nanocatalyst is a hydrogenation reaction catalyst.

[0012] Preferably, in the layered structure, the three metal cations of Cu, Zn and Al have an atomic-level arrangement structure in the cation layer;

[0013] The hydrotalcite-derived copper-based nanocatalyst includes zinc hydroxide, zinc oxide, aluminum hydroxide, aluminum oxide, copper oxide and metallic copper;

[0014] In the layered structure, the thickness of a single layer is 1 to 10 nm;

[0015] On the layered structure, the dispersion of metal Cu is 10% to 90%;

[0016] The hydrotalcite-derived copper-based nanocatalyst is a catalyst for preparing methanol by hydrogenating CO / CO2.

[0017] The present invention provides a method for preparing a hydrotalcite-derived copper-based nanocatalyst, comprising the following steps:

[0018] 1) mixing a copper source, a zinc source, an aluminum source and a solvent to obtain a mixed solution;

[0019] 2) adding a precipitant, and preparing the catalyst by a pH method, a colloid mill method, a urea-acetone method, and a hydrothermal synthesis method, washing with a mixed solution of water and ethanol, and drying to obtain a catalyst precursor of a layered double metal hydroxide;

[0020] The precipitant is a hydroxide-containing alkaline compound, a carbonate, a bicarbonate, a mixed alkaline solution of a hydroxide-containing alkaline compound and a carbonate and / or bicarbonate, or urea;

[0021] 3) The catalyst precursor obtained in the above step is subjected to a structural topological transformation treatment to obtain a hydrotalcite-derived copper-based nanocatalyst.

[0022] Preferably, the zinc source includes one or more of zinc nitrate hexahydrate, zinc acetate and zinc chloride;

[0023] The aluminum source includes one or more of aluminum nitrate nonahydrate, aluminum chloride hexahydrate, anhydrous aluminum chloride and aluminum oxide;

[0024] The copper source includes one or more of copper nitrate trihydrate, copper chloride and copper acetate;

[0025] The hydroxide-containing alkaline compound includes sodium hydroxide and / or potassium hydroxide;

[0026] The carbonate includes sodium carbonate and / or potassium carbonate;

[0027] The carbonate includes sodium bicarbonate and / or potassium bicarbonate.

[0028] Preferably, the molar ratio of the copper source to the zinc source, calculated on the basis of the moles of copper and zinc, is (0.1-10): (0.1-10);

[0029] The molar ratio of the hydroxide-containing alkaline compound to the carbonate is (0.1-5):(0.1-5);

[0030] The molar ratio of the hydroxide-containing alkaline compound to the bicarbonate is (0.1-5):(0.1-5);

[0031] The molar ratio of the urea to the metal ion is (2-28):1;

[0032] The volume ratio of the mixed solution of water and ethanol is (0-1):(0-1).

[0033] Preferably, the specific process of the pH method comprises the following steps:

[0034] 11) mixing a copper source, a zinc source, an aluminum source and water to obtain a mixed salt solution;

[0035] Mixing a hydroxide-containing alkaline compound, a carbonate and water to obtain a mixed alkaline solution;

[0036] 12) controlling the pH value, mixing the mixed salt solution and the mixed alkali solution obtained in the above step again, and then crystallizing them to obtain a catalyst precursor of a layered double metal hydroxide;

[0037] The specific process of the colloid mill method comprises the following steps:

[0038] 11') mixing a copper source, a zinc source, an aluminum source and water to obtain a mixed salt solution;

[0039] Mixing a hydroxide-containing alkaline compound, a carbonate and water to obtain a mixed alkaline solution;

[0040] 12') Controlling the pH value, mixing the mixed salt solution and the mixed alkali solution obtained in the above steps through a colloid mill and then crystallizing to obtain a catalyst precursor of a layered double metal hydroxide.

[0041] Preferably, the specific process of the urea-acetone method comprises the following steps:

[0042] 1a) mixing a copper source, a zinc source, an aluminum source, urea and water to obtain a mixed solution;

[0043] 1b) crystallizing the mixed solution obtained in the above step to separate the solid phase, and then mixing the solid phase with the ethanol solution of acetone again, and washing with the ethanol solution of acetone to obtain a catalyst precursor of a layered double metal hydroxide;

[0044] The specific process of the hydrothermal synthesis method comprises the following steps:

[0045] 1A) mixing a copper source, a zinc source, aluminum oxide and water to obtain a mixed solution;

[0046] Mixing urea and water to obtain a urea solution;

[0047] 1B) The mixed solution obtained in the above step and the urea solution are mixed again for hydrothermal reaction, and then crystallized to obtain a catalyst precursor of a layered double metal hydroxide.

[0048] Preferably, the topological transformation treatment is specifically a reduction treatment under a certain temperature, pressure and atmosphere;

[0049] The heating rate of the topological transformation treatment is 0.1 to 50°C / min;

[0050] The temperature of the topological transformation treatment is 160-1000° C.;

[0051] The topology transformation process takes 0.5 to 48 hours.

[0052] The pressure of the topological transformation treatment is 0.1 to 10 MPa;

[0053] The atmosphere includes reducing gas, a mixed gas of reducing gas and protective gas, air or different atmospheres are processed in sequence.

[0054] The present invention also provides the use of the hydrotalcite-derived copper-based nanocatalyst described in any one of the above technical solutions or the hydrotalcite-derived copper-based nanocatalyst prepared by the preparation method described in any one of the above technical solutions as a catalyst in the CO and / or CO2 hydrogenation reaction to produce methanol.

[0055] The present invention provides a hydrotalcite-derived copper-based nanocatalyst, wherein the hydrotalcite-derived copper-based nanocatalyst is obtained by subjecting a multimetal hydroxide precursor having a hydrotalcite intercalation structure to a structural topological transformation treatment; the metals include Cu, Zn and Al; and the hydrotalcite-derived copper-based nanocatalyst has a nano-level layered structure. Compared with the prior art, the present invention designs a hydrotalcite-derived copper-based nanocatalyst with a specific structure and composition, and its efficient Cu surface hydrogenation active sites and strong metal-carrier interaction can effectively increase the yield of methanol in the CO / CO2 hydrogenation reaction process and keep the catalyst excellently stable.

[0056] The present invention utilizes the adjustable ratio of metal elements in hydrotalcite, and through a specific structural topological transformation process, based on the controllable parameters of the structural topological transformation process, in particular, by regulating the heating rate to achieve control of the structural topological transformation process, the metal in the catalyst is highly dispersed and still maintains the characteristics of the intercalation structure, thereby achieving microstructural regulation of Cu in the Cu-based catalyst. The Cu-based catalyst prepared by the present invention has good Cu dispersion, and the geometric structure and electronic properties of the metal-carrier interface are adjustable. When it is used in the CO / CO2 hydrogenation reaction, it exhibits excellent reaction performance and high catalytic performance, and also has good stability.

[0057] The present invention also provides a preparation method of a corresponding talc-derived copper-based catalyst, which uses copper salt, zinc salt, aluminum salt, etc. as raw materials, an aqueous solution of a hydroxide-containing alkaline compound and a carbonate or urea as a precipitant, and adopts a pH method, a colloid mill method, a urea-acetone method, and a hydrothermal synthesis method using aluminum oxide as an aluminum source to prepare a hydrotalcite-derived copper-based nanocatalyst. The preparation method provided by the present invention has mild conditions, large selectivity, strong operability, and is more suitable for the promotion and application of industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1The SEM images of the hydrotalcite precursor and the hydrotalcite-derived copper-based nanocatalyst prepared by the present invention;

[0059] Figure 2 SEM images of hydrotalcite-derived copper-based nanocatalysts Cu-S5 and Cu-S6 prepared in the present invention;

[0060] Figure 3 The SEM images of the hydrotalcite-derived copper-based nanocatalysts Cu-S1-350 and Cu-S1-600 after the air atmosphere topological transformation treatment provided by the present invention;

[0061] Figure 4 This is a SEM image of the hydrotalcite-derived copper-based nanocatalyst Cu-S1-18% prepared in the present invention;

[0062] Figure 5 Mapping diagram of Cu, Zn and Al elements of the hydrotalcite-derived copper-based nanocatalyst Cu-S1-18% prepared in the present invention;

[0063] Figure 6 XANES and Fourier transformed EXAFS (R-space) spectra of Cu K-edge of Cu-S1-6%, Cu-S1, Cu-S1-18%, Cu foil, Cu2O and CuO. DETAILED DESCRIPTION

[0064] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples, but it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the invention.

[0065] All raw materials of the present invention have no particular limitation on their sources, and can be purchased from the market or prepared according to conventional methods known to those skilled in the art.

[0066] There is no particular limitation on the purity of all raw materials in the present invention. The present invention preferably adopts analytically pure raw materials or raw materials with conventional purity requirements in the field of hydrogenation reaction to produce methanol.

[0067] All raw materials and process steps of the present invention, their brands or abbreviations are conventional brands or abbreviations in the art, and each brand or abbreviation is clear and definite in the field of its related use. Those skilled in the art can purchase them from the market or prepare them by conventional methods, or implement them with corresponding equipment according to the brands, abbreviations and corresponding uses.

[0068] The present invention provides a hydrotalcite-derived copper-based nanocatalyst, wherein the hydrotalcite-derived copper-based nanocatalyst is obtained by subjecting a multi-metal hydroxide precursor having a hydrotalcite intercalation structure to a structural topological transformation treatment;

[0069] The metal includes Cu, Zn and Al;

[0070] The hydrotalcite-derived copper-based nanocatalyst has a nano-level layered structure.

[0071] In the present invention, the hydrotalcite-derived copper-based nanocatalyst preferably has a highly dispersed metal component. Specifically, on the layered structure, the dispersion of metal Cu is preferably 10% to 90%, more preferably 30% to 80%, and more preferably 50% to 70%.

[0072] In the present invention, in the copper-based catalyst, the molar ratio of Cu to Zn is preferably (0.1-10):(0.1-10), more preferably (0.5-8):(0.1-10), more preferably (1-5):(0.1-10), or (0.1-10):(0.5-8), or (0.1-10):(1-5).

[0073] In the present invention, in the copper-based catalyst, the molar ratio of the total molar number of Cu+Zn to Al is preferably (1-6):1, more preferably (2-4):1, and more preferably (3-5):1.

[0074] In the present invention, the hydrotalcite-derived copper-based nanocatalyst is preferably a hydrogenation reaction catalyst.

[0075] In the present invention, in the layered structure, the three metal cations of Cu, Zn and Al preferably have an atomic-level arrangement structure in the cation layer.

[0076] In the present invention, the hydrotalcite-derived copper-based nanocatalyst preferably includes zinc hydroxide, zinc oxide, aluminum hydroxide, aluminum oxide, copper oxide and metallic copper.

[0077] In the present invention, the hydrotalcite-derived copper-based nanocatalyst has a nano-scale layered structure, which can be understood as a nanosheet structure. The diameter of the nanosheet is preferably 100-1000 nm, more preferably 300-800 nm, and more preferably 400-700 nm.

[0078] In the present invention, the hydrotalcite-derived copper-based nanosheets are staggered and stacked to form a nano-flower structure, wherein pores are formed between the staggered and stacked nanosheets.

[0079] In the present invention, the thickness of the monolayer in the layered (sheet) structure is preferably 1 to 10 nm, more preferably 3 to 8 nm, and more preferably 5 to 6 nm. In the present invention, the layer thickness of the nano-scale layered structure of the hydrotalcite-derived copper-based nanocatalyst can be adjusted to a minimum of a monolayer. The sheet thickness can also be 1 to 50 nm.

[0080] In the present invention, the CO / CO2 specifically refers to CO and / or CO2.

[0081] In the present invention, the hydrotalcite-derived copper-based nanocatalyst is preferably a catalyst for CO / CO2 hydrogenation to methanol. Specifically, the CO / CO2 hydrogenation to methanol can be CO hydrogenation to methanol, CO2 hydrogenation to methanol, or CO and CO2 hydrogenation to methanol.

[0082] In the present invention, the hydrotalcite-derived copper-based nanocatalyst can be expressed as a hydrotalcite-derived Cu / ZnO / Al2O3 catalyst.

[0083] The present invention provides a method for preparing a hydrotalcite-derived copper-based nanocatalyst, comprising the following steps:

[0084] 1) mixing a copper source, a zinc source, an aluminum source and a solvent to obtain a mixed solution;

[0085] 2) adding a precipitant, and preparing the catalyst by a pH method, a colloid mill method, a urea-acetone method, and a hydrothermal synthesis method, washing with a mixed solution of water and ethanol, and drying to obtain a catalyst precursor of a layered double metal hydroxide;

[0086] The precipitant is a hydroxide-containing alkaline compound, a carbonate, a bicarbonate, a mixed alkaline solution of a hydroxide-containing alkaline compound and a carbonate and / or bicarbonate, or urea;

[0087] 3) The catalyst precursor obtained in the above step is subjected to a structural topological transformation treatment to obtain a hydrotalcite-derived copper-based nanocatalyst.

[0088] The invention firstly mixes a copper source, a zinc source, an aluminum source and a solvent to obtain a mixed solution.

[0089] In the present invention, the zinc source preferably includes one or more of zinc nitrate hexahydrate, zinc acetate and zinc chloride, and more preferably zinc nitrate hexahydrate, zinc acetate or zinc chloride.

[0090] In the present invention, the aluminum source preferably includes one or more of aluminum nitrate nonahydrate, aluminum chloride hexahydrate, anhydrous aluminum chloride and aluminum oxide, and more preferably aluminum nitrate nonahydrate, aluminum chloride hexahydrate, anhydrous aluminum chloride or aluminum oxide.

[0091] In the present invention, the copper source preferably includes one or more of copper nitrate trihydrate, copper chloride and copper acetate, and more preferably copper nitrate trihydrate, copper chloride or copper acetate.

[0092] The present invention further adds a precipitant, adopts a pH method, a colloid mill method, a urea-acetone method and a hydrothermal synthesis method for preparation, and after washing and drying with a mixed solution of water and ethanol, obtains a catalyst precursor of a layered double metal hydroxide. The precipitant is a hydroxide-containing alkaline compound, a carbonate, a bicarbonate, a mixed alkaline solution of a hydroxide-containing alkaline compound and a carbonate and / or bicarbonate, and urea.

[0093] It should be pointed out that layered double hydroxide is a common expression in the art, that is, layered double hydroxide (LDH) is a general term for hydrotalcite (HT) and hydrotalcite-like compounds (HTLCs), so the catalyst precursor in the present invention has a hydrotalcite structure, which is also a common expression in the industry. Specifically, the catalyst precursor in the present invention is a layered trimetallic hydroxide (Cu, Zn and Al) with a hydrotalcite structure.

[0094] In the present invention, the hydroxide-containing alkaline compound preferably includes sodium hydroxide and / or potassium hydroxide, more preferably sodium hydroxide or potassium hydroxide.

[0095] In the present invention, the carbonate preferably includes sodium carbonate and / or potassium carbonate, more preferably sodium carbonate or potassium carbonate.

[0096] In the present invention, the carbonate preferably includes sodium bicarbonate and / or potassium bicarbonate, more preferably sodium bicarbonate or potassium bicarbonate.

[0097] In the present invention, the molar ratio of the copper source to the zinc source, calculated on the basis of the moles of copper and zinc, is preferably (0.1-10):(0.1-10), more preferably (0.5-8):(0.1-10), more preferably (1-5):(0.1-10), or (0.1-10):(0.5-8), or (0.1-10):(1-5).

[0098] In the present invention, the molar ratio of the hydroxide-containing alkaline compound to the carbonate is preferably (0.1-5):(0.1-5), more preferably (0.5-4):(0.1-5), more preferably (1-3):(0.1-5), or (0.1-5):(0.5-4), or (0.1-5):(1-3).

[0099] In the present invention, the molar ratio of the hydroxide-containing alkaline compound to the bicarbonate is preferably (0.1-5):(0.1-5), more preferably (0.5-4):(0.1-5), more preferably (1-3):(0.1-5), or (0.1-5):(0.5-4), or (0.1-5):(1-3).

[0100] In the present invention, the molar ratio of urea to metal ions is preferably (2-28):1, more preferably (7-23):1, and more preferably (12-18):1.

[0101] In the present invention, the specific process of the pH method preferably includes the following steps:

[0102] 11) mixing a copper source, a zinc source, an aluminum source and water to obtain a mixed salt solution;

[0103] Mixing a hydroxide-containing alkaline compound, a carbonate and water to obtain a mixed alkaline solution;

[0104] 12) controlling the pH value, mixing the mixed salt solution and the mixed alkali solution obtained in the above step again, and then crystallizing them to obtain a catalyst precursor of a layered double metal hydroxide;

[0105] In the present invention, the specific process of the colloid mill method preferably includes the following steps:

[0106] 11') mixing a copper source, a zinc source, an aluminum source and water to obtain a mixed salt solution;

[0107] Mixing a hydroxide-containing alkaline compound, a carbonate and water to obtain a mixed alkaline solution;

[0108] 12') Controlling the pH value, mixing the mixed salt solution and the mixed alkali solution obtained in the above steps through a colloid mill and then crystallizing to obtain a catalyst precursor of a layered double metal hydroxide.

[0109] In the present invention, the specific process of the urea-acetone method preferably comprises the following steps:

[0110] 1a) mixing a copper source, a zinc source, an aluminum source, urea and water to obtain a mixed solution;

[0111] 1b) crystallizing the mixed solution obtained in the above step to separate the solid phase, and then mixing the solid phase with the ethanol solution of acetone again, and washing with the ethanol solution of acetone to obtain a catalyst precursor of a layered double metal hydroxide;

[0112] In the present invention, the specific process of the hydrothermal synthesis method preferably includes the following steps:

[0113] 1A) mixing a copper source, a zinc source, aluminum oxide and water to obtain a mixed solution;

[0114] Mixing urea and water to obtain a urea solution;

[0115] 1B) The mixed solution obtained in the above step and the urea solution are mixed again for hydrothermal reaction, and then crystallized to obtain a catalyst precursor of a layered double metal hydroxide.

[0116] Finally, the catalyst precursor obtained in the above steps is subjected to a structural topological transformation treatment to obtain a hydrotalcite-derived copper-based nanocatalyst.

[0117] In the present invention, the structural topological transformation treatment is specifically a reduction treatment under a certain temperature, pressure and atmosphere. This process can maintain the structural characteristics of the catalyst precursor during the transformation of the catalyst precursor, so it is a topological transformation.

[0118] In the present invention, the heating rate of the topological transformation treatment is preferably 0.1 to 50° C. / min, more preferably 1 to 40° C. / min, and more preferably 10 to 30° C. / min.

[0119] In the present invention, the temperature of the topological transformation treatment is preferably 160 to 1000°C, more preferably 300 to 800°C, and even more preferably 400 to 700°C.

[0120] In the present invention, the time of the topological transformation treatment is preferably 0.5 to 48 hours, more preferably 5.5 to 42 hours, more preferably 12 to 36 hours, and more preferably 18 to 30 hours.

[0121] In the present invention, the pressure of the topological transformation treatment is preferably 0.1 to 10 MPa, more preferably 2 to 8 MPa, and more preferably 4 to 6 MPa.

[0122] In the present invention, the atmosphere preferably includes reducing gas, a mixed gas of reducing gas and protective gas, air or different atmospheres in sequence. Wherein, the different atmospheres in sequence specifically include topological transformation treatment in sequence under different atmosphere conditions. Specifically, the reducing gas includes one or more of hydrogen, methane and ammonia.

[0123] The hydrotalcite-derived copper-based nanocatalyst prepared by the present invention particularly adopts a double-layer metal hydroxide with a hydrotalcite intercalation structure as a catalyst precursor, so that the prepared hydrotalcite-derived copper-based nanocatalyst has a nano-level layered structure, and its layer plate metal cations are arranged at the atomic level and interact with the interlayer anions; the composition and proportion of its interlayer metal cations such as copper and interlayer anions such as carbonate can be regulated. The present invention can regulate the metal electron cloud density of layer plate copper and the dispersion degree of active sites and the metal-carrier interaction by affecting the structural topological transformation process of the copper-based hydrotalcite precursor, thereby achieving the regulation of the microscopic geometric structure of Cu, the good dispersibility of Cu and the electronic characteristics of the Cu-carrier surface interface structure, and the layer plate confinement effect inhibits the migration and aggregation of Cu components.

[0124] The catalyst provided by the present invention is prepared from an LDHs precursor, and the LDHs precursor has an intercalation structure of cations and anions formed by metal cations and anions such as hydroxide, and the cation layer plate has an atomic-level arrangement of multiple metal cations, so that after the topological transformation, the metal cations are evenly distributed and the microstructure is better regulated, and the nano-level layered structure is maintained as a whole.

[0125] The present invention provides the use of the hydrotalcite-derived copper-based nanocatalyst described in any one of the above technical solutions or the hydrotalcite-derived copper-based nanocatalyst prepared by the preparation method described in any one of the above technical solutions as a catalyst in the reaction of hydrogenating CO and / or CO2 to produce methanol.

[0126] The present invention is to complete and refine the overall technical solution, better ensure the overall structure of the hydrotalcite-derived copper-based nanocatalyst, and further improve the catalytic performance of the hydrotalcite-derived copper-based nanocatalyst in the hydrogenation reaction. The above-mentioned hydrotalcite-derived copper-based nanocatalyst for CO / CO2 hydrogenation to methanol and its preparation method and application may specifically include the following contents:

[0127] A preparation method and application of a hydrotalcite-derived copper-based nanocatalyst for CO / CO2 hydrogenation to methanol, comprising the following steps:

[0128] Cu 2+ Copper salts, Zn 2+ Zinc salts and Al 3+ The aluminum salt is mixed with water as solvent, stirred thoroughly to dissolve completely, and a mixed salt solution is prepared ①; the alkaline compound containing hydroxide and carbonate are prepared into a mixed alkaline solution ②.

[0129] In another beaker, add 0-100mL of water, slowly drip the alkaline solution and salt solution into it respectively, and continue to stir, and use a pH meter to control the pH of the suspension to 7-14. After all the salt solutions are added, move the suspension into a constant temperature water bath, control the crystallization temperature to 40-100°C, and continue to stir for 1-48h. After the crystallization is completed, perform solid-liquid separation, and wash the solid with a mixed solution of water and ethanol until it is neutral, and then place the solid in a constant temperature box at 40-90°C to dry for 6-48h.

[0130] The obtained catalyst precursor is a layered double metal hydroxide, and the obtained solid powder is further subjected to a structural topological transformation treatment to obtain a hydrotalcite-derived copper-based nanocatalyst Cu-S1 with an intercalated structure.

[0131] A preparation method and application of a hydrotalcite-derived copper-based nanocatalyst for CO / CO2 hydrogenation to methanol, comprising the following steps:

[0132] Cu 2+ Copper salts, Zn 2+ Zinc salts and Al 3+ The aluminum salt is mixed with water as solvent, stirred thoroughly to dissolve completely, and a mixed salt solution is prepared ①; the alkaline compound containing hydroxide and carbonate are prepared into a mixed alkaline solution ②.

[0133] The metal salt solution and the alkali solution are quickly added to the colloid mill reactor and mixed at a speed of 1000-10000r. The mixture is stirred for 0.5-60 minutes. After the crystallization is completed, the solid-liquid separation is performed, and the solid is washed with a mixed solution of water and ethanol until it is neutral. The solid is then placed in a constant temperature box at 40-90°C and dried for 6-48 hours.

[0134] The obtained catalyst precursor is a layered double metal hydroxide, and the obtained solid powder is further subjected to a structural topological transformation treatment to obtain a hydrotalcite-derived copper-based nanocatalyst Cu-S2 with an intercalated structure.

[0135] A preparation method and application of a hydrotalcite-derived copper-based nanocatalyst for CO / CO2 hydrogenation to methanol, comprising the following steps:

[0136] Cu 2+ Copper salts, Zn 2+ Zinc salt, Al 3+ Aluminum salt and a certain amount of urea are mixed with water as solvent, stirred thoroughly to completely dissolve them and prepare a mixed solution.

[0137] Then, the mixed solution is placed in a three-necked flask, transferred to an oil bath / sand bath, and the crystallization temperature is controlled at 60-180°C, and stirred continuously for crystallization for 1-48 hours. (Or: the mixed solution is placed in the lining of a hydrothermal reactor and stirred for 1-48 hours, and then the reactor is moved to a constant temperature box at 90-180°C and crystallized for 8-48 hours.) After the crystallization is completed, solid-liquid separation is performed, and the solid is washed with a mixed solution of water and ethanol until it is neutral.

[0138] The obtained wet cake solid sample was redispersed in 50-1000 mL of acetone and stirred at room temperature for 1-48 hours, then washed with acetone and dried in a vacuum oven at 20-90° C. for 2-48 hours.

[0139] The obtained catalyst precursor is a layered double metal hydroxide, and the obtained solid powder is further subjected to a structural topological transformation treatment to obtain a hydrotalcite-derived copper-based nanocatalyst Cu-S3 with an intercalated structure.

[0140] A preparation method and application of a hydrotalcite-derived copper-based nanocatalyst for CO / CO2 hydrogenation to methanol, comprising the following steps:

[0141] Cu 2+ Copper salts, Zn 2+ Use water as solvent to stir the zinc salt and aluminum oxide thoroughly to dissolve them completely to prepare a mixed solution ①; dissolve urea in water to prepare a mixed solution ②.

[0142] Then, the mixed solution ① and the mixed solution ② are placed in the inner lining of the hydrothermal reactor and stirred for 1 to 48 hours, and then the reactor is moved to a thermostat at 60 to 180°C for crystallization for 1 to 48 hours. (Or: Then, the mixed solution ① and the mixed solution ② are placed in a three-necked flask, moved into an oil bath pot / sand bath pot, the crystallization temperature is controlled at 60 to 180°C, and stirred continuously for crystallization for 1 to 48 hours.) After the crystallization is completed, the solid-liquid separation is performed, and the solid is washed with a mixed solution of water and ethanol until it is neutral, and then the solid is placed in a thermostat at 40 to 90°C for drying for 2-48 hours.

[0143] The obtained catalyst precursor is a layered double metal hydroxide, and the obtained solid powder is further subjected to a structural topological transformation treatment to obtain a hydrotalcite-derived copper-based nanocatalyst Cu-S4 with an intercalated structure.

[0144] Specifically, the zinc ions are provided by one or more of zinc nitrate hexahydrate, zinc acetate, and zinc chloride.

[0145] Specifically, the aluminum ions are provided by one or more of aluminum nitrate nonahydrate, aluminum chloride hexahydrate, and anhydrous aluminum chloride.

[0146] Specifically, the copper ions are provided by one or more of copper nitrate trihydrate, copper chloride, and copper acetate.

[0147] Specifically, the molar ratio of zinc ions to aluminum ions is (1-4):1.

[0148] Specifically, the sum of the molar concentrations of the zinc ions and the aluminum ions is 0.1 to 1 mol / L.

[0149] Specifically, the molar concentration of the copper ions is 0.001 to 1 mol / L.

[0150] Specifically, the molar ratio of the copper ions to the zinc ions is (10-1500):1000.

[0151] Specifically, the hydroxide-containing alkaline compound is selected from sodium hydroxide or potassium hydroxide; and the carbonate is selected from sodium carbonate or potassium carbonate.

[0152] Specifically, the molar ratio of the hydroxide-containing alkaline compound to the carbonate is (1-5):1.

[0153] Specifically, the sum of the molar concentrations of the hydroxide-containing alkaline compound and the carbonate is 0.5 to 5 mol / L.

[0154] Specifically, the ratio of the amount of urea to the amount of metal ion substance is 7-28.

[0155] Specifically, the volume ratio of the aqueous solution ① to the aqueous solution ② is (0.1-5):1.

[0156] Specifically, the volume ratio of the mixed solution of water and ethanol is (0.1-1):(0.1-1).

[0157] Specifically, in the structural topological transformation treatment, the atmosphere is selected from one or more of vacuum, nitrogen, argon, helium, air, and hydrogen, the structural topological transformation temperature is 200-1000°C, and the time is 2-24h; the hydrogen treatment temperature is 250-350°C, and the time is 2-24h.

[0158] Specifically, the structural topology transformation treatment further includes hydrogen treatment, the hydrogen treatment temperature is 250-350° C., and the time is 2 to 24 hours.

[0159] Specifically, the reaction conditions include: reaction temperature of 180-300°C; reaction pressure of 0.1-10MPa; reaction mixture H2:CO / CO2 of 1-6; mass space velocity of 4000-20000h -1 ; The volume flow rate of the mixed gas of CO / CO2 and H2 is 10-500mL / min; the balance gas of the mixed gas is selected from one or more of nitrogen, argon and helium.

[0160] Specifically, the Cu-based catalyst is used as a hydrogenation catalyst and directly contacts and reacts with a reaction gas containing CO / CO2 and hydrogen to obtain methanol and water.

[0161] Further:

[0162] Preferably, the zinc ions are provided by one or more of zinc nitrate hexahydrate, zinc acetate, and zinc chloride; more preferably, the zinc ions are provided by zinc nitrate hexahydrate.

[0163] Preferably, the aluminum ions are provided by one or more of aluminum nitrate nonahydrate, aluminum chloride hexahydrate, and anhydrous aluminum chloride; more preferably, the aluminum ions are provided by aluminum nitrate nonahydrate.

[0164] Preferably, the copper ions are provided by one or more of copper nitrate trihydrate, copper chloride, and copper acetate; more preferably, the copper ions are provided by copper nitrate trihydrate.

[0165] Preferably, the molar ratio of zinc ions to aluminum ions is (1-4):1; more preferably (2-4):1; further preferably 2:1.

[0166] Preferably, the sum of the molar concentrations of the zinc ions and the aluminum ions is 0.1 to 1 mol / L; more preferably 0.2 to 0.5 mol / L; further preferably 0.3 mol / L.

[0167] Preferably, the molar concentration of the copper ions is 0.001 to 1 mol / L; more preferably 0.01 to 0.3 mol / L.

[0168] Preferably, the molar ratio of the copper ions to the zinc ions is (10-1500):1000; more preferably (100-1100):1000.

[0169] Preferably, the hydroxide-containing alkaline compound is selected from sodium hydroxide or potassium hydroxide; more preferably, the hydroxide-containing alkaline compound is sodium hydroxide.

[0170] Preferably, the carbonate is selected from sodium carbonate or potassium carbonate; more preferably, the carbonate is sodium carbonate.

[0171] Preferably, the molar ratio of the hydroxide-containing alkaline compound to the carbonate is (1-5):1; more preferably (1-4):1; further preferably 4:1.

[0172] Preferably, the sum of the molar concentrations of the hydroxide-containing alkaline compound and the carbonate is 0.5 to 5 mol / L; more preferably 1 to 3 mol / L; further preferably 1.2 mol / L.

[0173] Preferably, the ratio of the amount of urea to the amount of metal ion substance is 7-28.

[0174] The aqueous solutions ① and ② of the present invention both use one or more of distilled water, deionized water, and ultrapure water as solvent; more preferably, deionized water is used as solvent.

[0175] Preferably, the volume ratio of the aqueous solution ① to the aqueous solution ② is (0.1-5):1, and more preferably (0.5-2):1. In some specific embodiments of the present invention, the volume ratio of the aqueous solution ① to the aqueous solution ② is 1:1.

[0176] Preferably, the pH value of the reaction is 8-14; more preferably, the pH value is 8.5-10.

[0177] Preferably, in the process of mixing the aqueous solution ① and the aqueous solution ②, the pH value of the system is controlled to remain unchanged. Specifically, the pH value can be controlled to remain unchanged by controlling the dropping speed and the stirring speed.

[0178] The present invention monitors the pH value of the system through a pH meter and controls it to remain unchanged, thereby ensuring that the carrier (zinc-aluminum hydrotalcite layer) has suitable alkaline properties, thereby reducing the problem of carbon deposition and deactivation of the catalyst occurring during the hydrogenation reaction.

[0179] Preferably, the reaction speed is 3000-10000r; more preferably, the reaction speed is 6000-8000r.

[0180] Preferably, the volume ratio of the mixed solution of water and ethanol is 1:1.

[0181] In the preparation method of the present invention, after the crystallization is completed, solid-liquid separation is performed, and the solid is washed with a mixed solution of water and ethanol until it becomes neutral.

[0182] The present invention has no particular limitation on the washing method described in the above preparation method, and the washing method may be a method well known to those skilled in the art, such as centrifugation, vacuum filtration, normal pressure filtration, etc.

[0183] After washing the above crystals, they are dried and subjected to structural topological transformation treatment.

[0184] The present invention has no particular limitation on the drying method described in the above preparation method, and it can be a method well known to those skilled in the art, such as normal pressure drying, vacuum drying, freeze drying, etc.

[0185] Preferably, the atmosphere for the structural topological transformation treatment is selected from one or more of vacuum, nitrogen, argon, helium and air; more preferably, the atmosphere for the structural topological transformation treatment is air and hydrogen in sequence.

[0186] Preferably, the temperature of the air atmosphere during the structural topological transformation process is 200-700°C; more preferably, the temperature is 350, 500 and 600°C.

[0187] Preferably, the heating rate of the air atmosphere during the structural topological transformation process is 1-20°C / min; more preferably, the heating rate is 3°C / min.

[0188] Preferably, the constant temperature time of the air atmosphere during the structural topological transformation treatment is 2 to 6 hours; more preferably, the time is 4 hours.

[0189] Preferably, the volume content of hydrogen in the hydrogen atmosphere during the structural topological transformation treatment is 5%-100%; more preferably, the volume content of hydrogen is 20%.

[0190] Preferably, the temperature of the hydrogen atmosphere in the structural topological transformation treatment is 250-400°C; more preferably, the temperature is 300°C.

[0191] Preferably, the heating rate of the hydrogen atmosphere in the structural topological transformation treatment is 1-20°C / min; more preferably, the heating rate is 3°C / min.

[0192] Preferably, the constant temperature time of the hydrogen atmosphere in the structural topological transformation treatment is 2 to 6 hours; more preferably, the time is 2 hours.

[0193] The specific composition of the Cu-based catalyst is Cu / ZnO / Al2O3. Due to the complex components of the catalyst, only its elemental composition is shown here.

[0194] The present invention also provides a method for preparing a hydrotalcite-derived copper-based nanocatalyst for hydrogenating CO / CO2 to produce methanol and its application. The hydrotalcite-derived copper-based nanocatalyst prepared by the above-mentioned preparation method is used as a hydrogenation catalyst and directly contacted with a reaction gas containing CO / CO2 and H2 to react to obtain methanol and water.

[0195] The present invention has no particular limitation on the reactor for the CO / CO2 hydrogenation reaction to prepare methanol, and it may be a fixed bed reactor.

[0196] Preferably, the volume ratio of CO / CO2 to H2 in the reaction gas is 1 to 6, more preferably 3 to 5. Further preferably, the volume ratio of CO / CO2 to H2 in the reaction gas is 3.

[0197] Preferably, the volume flow rate of the mixed gas of CO / CO2 and H2 is 10 to 500 mL / min.

[0198] Preferably, the reaction gas balance gas is selected from one or more of nitrogen, argon and helium.

[0199] Preferably, the mass space velocity of the CO / CO2 hydrogenation to methanol reaction is 4000-20000h -1 .

[0200] Preferably, the reaction temperature of the CO / CO2 hydrogenation to synthesize methanol is 180-300°C, more preferably 200-300°C. In some specific embodiments of the present invention, the temperature of the CO2 hydrogenation reaction is 200°C, 230°C, the temperature of the CO hydrogenation reaction is 250°C, and the temperature of the CO and CO2 hydrogenation reaction is 250°C, which is conducive to reducing side reactions caused by overheating.

[0201] Preferably, the reaction pressure is 0.1-10 MPa; more preferably, it is 3-5 MPa; further preferably, the CO2 hydrogenation reaction pressure is 3 MPa, the CO hydrogenation reaction pressure is 5 MPa, and the CO and CO2 hydrogenation reaction pressure is 5 MPa.

[0202] The above content of the present invention provides a hydrotalcite-derived copper-based nanocatalyst for CO / CO2 hydrogenation to methanol and its preparation method and application. The hydrotalcite-derived copper-based nanocatalyst designed by the present invention has a specific structure and composition, and its efficient Cu surface hydrogenation active sites and strong metal-support interaction can effectively increase the yield of methanol during the CO / CO2 hydrogenation reaction and keep the catalyst with excellent activity and selectivity.

[0203] The present invention utilizes the adjustable ratio of metal elements in hydrotalcite, and through a specific structural topological transformation process, based on the controllable parameters of the structural topological transformation process, in particular, by regulating the heating rate to achieve control of the structural topological transformation process, the metal in the catalyst is highly dispersed and still maintains the characteristics of the intercalation structure, thereby achieving microstructural regulation of Cu in the Cu-based catalyst. The Cu-based catalyst prepared by the present invention has good Cu dispersion, and the geometric structure and electronic properties of the metal-carrier interface are adjustable. When it is used in the CO / CO2 hydrogenation reaction, it exhibits excellent reaction performance and high catalytic performance, and also has good stability.

[0204] The present invention also provides a preparation method of a corresponding talc-derived copper-based catalyst, which uses copper salt, zinc salt, aluminum salt, etc. as raw materials, an aqueous solution of a hydroxide-containing alkaline compound and a carbonate or urea as a precipitant, and adopts a pH method, a colloid mill method, a urea-acetone method, and a hydrothermal synthesis method using aluminum oxide as an aluminum source to prepare a hydrotalcite-derived copper-based nanocatalyst. The preparation method provided by the present invention has mild conditions, large selectivity, strong operability, and is more suitable for the promotion and application of industrial production.

[0205] In order to further illustrate the present invention, a hydrotalcite-derived copper-based nanocatalyst and its preparation method and application provided by the present invention are described in detail below in combination with examples. However, it should be understood that these examples are implemented on the premise of the technical solution of the present invention, and detailed implementation methods and specific operation processes are given only to further illustrate the features and advantages of the present invention, rather than to limit the claims of the present invention, and the protection scope of the present invention is not limited to the following examples.

[0206] Example 1

[0207] (I) Preparation of Cu-S1 catalyst

[0208] 1) Copper nitrate trihydrate, zinc nitrate hexahydrate and aluminum nitrate nonahydrate are added in a molar ratio of divalent ions to trivalent ions of 2:1, deionized water is used as the solvent, and it is fully stirred to completely dissolve to prepare a 100mL, 0.33mol / L mixed salt solution. Sodium hydroxide and sodium carbonate are prepared into a 100mL, 1.24mol / L mixed alkali solution, which is fully stirred to completely dissolve. In another beaker, 50mL of distilled water is added, and the alkali solution and the salt solution are slowly dripped into them respectively, and stirred continuously, and the pH of the suspension is controlled by a pH meter to be 9.5±0.5. After all the salt solutions are added, the suspension is moved into a constant temperature water bath, the crystallization temperature is controlled to 60°C, and stirred continuously for crystallization for 10h. After the crystallization is completed, solid-liquid separation is performed, and the solid is washed with a mixed solution of deionized water and ethanol until it is neutral, and then the solid is placed in a 60°C constant temperature box to dry for 6-12h. The obtained catalyst precursor is a layered double metal hydroxide. The obtained solid powder is further subjected to a structural topological transformation treatment. The temperature is raised to 500°C at 3°C / min in an air atmosphere for 4 h. Finally, the catalyst is heated at 300°C with a total flow rate of 100 mL·min -1 , 3℃ / min, H2:N2 ratio of 1:4 mixed gas reduction for 2h to obtain the hydrotalcite-derived copper-based nanocatalyst Cu-S1 with an intercalated structure.

[0209] In the Cu-S1 catalyst provided in this embodiment, based on the mass of the catalyst being 100%, the mass content of Cu is 10 wt%.

[0210] (ii) Cu-S1 catalyst for CO and / or CO2 hydrogenation

[0211] Weigh 0.5g of Cu-S1 catalyst and 0.5g of 40-60 mesh quartz sand and mix them evenly. Place the mixture in a quartz reaction tube and introduce a hydrogen-nitrogen mixed gas with a total volume flow rate of 100mL / min and a hydrogen volume concentration of 20%, 3℃ / min, and pretreat at 300℃ for 2h. After the pretreatment is completed and the reduction is completed, turn off the H2 gas, use N2 to pressurize and detect leaks, and turn off N2 after confirming that there is no leakage. Introduce the mixed reaction gas and pressurize it to 3MPa, raise the temperature to the reaction temperature, and adjust the mixed gas flow rate to 80mL·min -1 .

[0212] Reaction product monitoring: During the reaction process, the products of different reaction times are analyzed. The detection method is: after the reaction reaches a steady state, the products of the reaction system are collected every 20 minutes.

[0213] The obtained CO and / or CO2 hydrogenation reaction performances are shown in Tables 1 to 3.

[0214] See Table 1, which shows the results of the hydrotalcite-derived copper-based nanocatalyst prepared in the embodiment of the present invention and the catalyst prepared in the comparative example in the CO2 hydrogenation to prepare methanol reaction at 200°C.

[0215] See Table 2, which shows the results of the hydrotalcite-derived copper-based nanocatalyst prepared in the embodiment of the present invention and the catalyst prepared in the comparative example in the CO hydrogenation to methanol reaction at 250°C.

[0216] See Table 3, which shows the results of the hydrotalcite-derived copper-based nanocatalyst prepared in the embodiment of the present invention and the catalyst prepared in the comparative example in the reaction of hydrogenating a mixture of CO and CO2 to produce methanol at 250°C.

[0217] Example 2

[0218] (I) Preparation of Cu-S2 catalyst

[0219] 1) Copper nitrate trihydrate, zinc nitrate hexahydrate and aluminum nitrate nonahydrate were added at a molar ratio of divalent ions to trivalent ions of 2:1, and deionized water was used as the solvent. They were fully stirred to completely dissolve and prepared into a 100mL, 0.33mol / L mixed salt solution. Sodium hydroxide and sodium carbonate were prepared into a 100mL, 1.24mol / L mixed alkali solution, which was fully stirred to completely dissolve. The metal salt solution and the alkali solution were quickly added to the colloid mill reactor and mixed at a speed of 6000r and stirred for 10 minutes. After crystallization, solid-liquid separation was performed, and the solid was washed with a mixed solution of deionized water and ethanol until neutral. The solid was then placed in a thermostat at 60°C and dried for 6-12h. The obtained catalyst precursor was a layered double metal hydroxide, and the obtained solid powder was further subjected to a structural topological transformation treatment, treated at 3°C / min in an air atmosphere, 500°C for 4h, and finally at 300°C with a total flow rate of 100mL·min -1 , 3℃ / min, H2:N2 ratio of 1:4 mixed gas reduction for 2h to obtain the hydrotalcite-derived copper-based nanocatalyst Cu-S2 with an intercalated structure.

[0220] In the Cu-S2 catalyst provided in this embodiment, based on the mass of the catalyst being 100%, the mass content of Cu is 10 wt%.

[0221] (ii) Cu-S2 catalyst catalyzes CO and / or CO2 hydrogenation

[0222] This method is the same as the method for catalytic hydrogenation of CO and / or CO2 provided in Example 1, but the difference is that the catalyst is Cu-S2 catalyst, and the rest is the same as Example 1.

[0223] The reaction product detection method is the same as in Example 1. The obtained CO and / or CO2 hydrogenation reaction performances are shown in Tables 1 to 3.

[0224] Example 3

[0225] (I) Preparation of Cu-S3 catalyst

[0226] 1) Copper nitrate trihydrate, zinc nitrate hexahydrate and aluminum nitrate nonahydrate were added at a molar ratio of divalent ions to trivalent ions of 2:1, and urea was added. Deionized water was used as a solvent, and the mixture was stirred thoroughly to completely dissolve and form a mixed solution. The mixed solution was then placed in a three-necked flask, moved into a constant temperature water bath, the crystallization temperature was controlled to be 100°C, and the mixture was stirred continuously for crystallization for 10 hours. After the crystallization was completed, solid-liquid separation was performed, and the solid was washed with a mixed solution of deionized water and ethanol until neutral. The obtained wet cake solid sample was redispersed in 200mL acetone and stirred at room temperature for 2 hours. Then, it was washed with acetone and placed in a vacuum oven at 40°C for 6-12h. The obtained catalyst precursor was a layered double metal hydroxide, and the obtained solid powder was further subjected to a structural topological transformation treatment, treated in an air atmosphere, 3°C / min, 500°C for 4h, and finally at 300°C with a total flow rate of 100mL·min -1 , reduced in a mixed gas of H2:N2 ratio of 1:4 at 3℃ / min for 2h to obtain a hydrotalcite-derived copper-based nanocatalyst Cu-S3 with an intercalated structure.

[0227] In the Cu-S3 catalyst provided in this embodiment, based on the mass of the catalyst being 100%, the mass content of Cu is 10 wt%.

[0228] (ii) Cu-S3 catalyst for CO and / or CO2 hydrogenation

[0229] This method is the same as the method for catalytic hydrogenation of CO and / or CO2 provided in Example 1, the difference being that the Cu-S3 catalyst is used as the catalyst, and the rest is the same as in Example 1.

[0230] The reaction product detection method is the same as in Example 1. The obtained CO and / or CO2 hydrogenation reaction performances are shown in Tables 1 to 3.

[0231] Example 4

[0232] (I) Preparation of Cu-S4 catalyst

[0233] Copper nitrate trihydrate, zinc nitrate hexahydrate and aluminum nitrate nonahydrate were added in a molar ratio of divalent ions to trivalent ions of 2:1, and deionized water was used as the solvent. They were fully stirred to completely dissolve to prepare a mixed solution ①; urea was dissolved in deionized water to prepare a mixed solution ②. Then, mixed solution ① and mixed solution ② were placed in the lining of a hydrothermal reactor and stirred for 2 hours, and then the reactor was moved to a constant temperature box at 100°C for crystallization for 24 hours. After the crystallization was completed, solid-liquid separation was carried out, and the solid was washed with a mixed solution of deionized water and ethanol until neutral, and then the solid was placed in a constant temperature box at 60°C for 6-12 hours. The obtained catalyst precursor is a layered double metal hydroxide, and the obtained solid powder was further subjected to a structural topological transformation treatment, 3°C / min, 500°C in an air atmosphere for 4 hours, and finally at 300°C with a total flow rate of 100mL·min -1 , reduced in a mixed gas of H2:N2 ratio of 1:4 at 3℃ / min for 2h to obtain a hydrotalcite-derived copper-based nanocatalyst Cu-S4 with an intercalated structure.

[0234] In the Cu-S4 catalyst provided in this embodiment, based on the mass of the catalyst being 100%, the mass content of Cu is 10 wt%.

[0235] (ii) Cu-S4 catalyst catalyzes CO and / or CO2 hydrogenation

[0236] This method is the same as the method for catalytic hydrogenation of CO and / or CO2 provided in Example 1, the difference being that the Cu-S4 catalyst is used as the catalyst, and the rest is the same as in Example 1.

[0237] The reaction product detection method is the same as in Example 1. The obtained CO and / or CO2 hydrogenation reaction performances are shown in Tables 1 to 3.

[0238] Comparative Example 1

[0239] (I) Preparation of Cu-S5 catalyst

[0240] This comparative example provides a copper-based catalyst prepared by impregnation method using ZnO / Al2O3 as a carrier, denoted as Cu-S5. The specific preparation method of the catalyst is as follows:

[0241] Weigh aluminum nitrate nonahydrate to make a 0.1 mol / L solution, add spherical ZnO powder to the aluminum nitrate nonahydrate solution and ultrasonicate for 1 hour, then let it stand at room temperature overnight, dry in a constant temperature box at 90°C, and then calcine at 500°C for 4 hours at 3°C / min in an air atmosphere. Take 1g of the calcined ZnO / Al2O3 mixture powder and add it to 50mL of copper nitrate trihydrate solution, and the molar ratio of Zn:Al is 2:1, keeping it with the same acid-base properties as the LDHs-based catalytic material, then ultrasonicate for 1 hour, let it stand overnight, and also calcine at 500°C for 4 hours at 3°C / min in an air atmosphere, and finally at 300°C with a total flow rate of 100mL·min -1 , reduced in a mixed gas of H2:N2 ratio of 1:4 at 3℃ / min for 2h to obtain Cu-S5 catalyst.

[0242] In the Cu / ZnO / Al2O3 catalyst provided in this comparative example, based on the mass of the catalyst being 100%, the mass content of Cu is 10 wt%.

[0243] (ii) Cu-S5 catalyst for CO and / or CO2 hydrogenation

[0244] This method is the same as the method for catalytic hydrogenation of CO and / or CO2 provided in Example 1, except that the catalyst is the Cu-S5 catalyst provided in this comparative example, and the rest is the same as in Example 1.

[0245] The reaction product detection method is the same as in Example 1. The obtained CO and / or CO2 hydrogenation reaction performances are shown in Tables 1 to 3.

[0246] Comparative Example 2

[0247] (I) Preparation of Cu-S6 catalyst

[0248] This comparative example provides a copper-based catalyst prepared by an impregnation method using zinc-aluminum hydrotalcite as a carrier, denoted as Cu-S6. The specific preparation method of the catalyst is as follows:

[0249] Zinc nitrate hexahydrate and aluminum nitrate nonahydrate Zn 2+ and Al 3+The molar ratio of is 2:1 for feeding, deionized water is used as the solvent, and a mixed salt solution of 100mL, 0.3mol / L is prepared to completely dissolve it. Sodium hydroxide and sodium carbonate are prepared into a mixed alkali solution of 100mL, 1.24mol / L, and stirred thoroughly to completely dissolve it. In another beaker, 50mL of distilled water is added, and the alkali solution and the salt solution are slowly dripped into them respectively, and stirred continuously, and the pH of the suspension is controlled by a pH meter to be 9.5±0.5. After all the salt solutions are added, the suspension is moved into a constant temperature water bath, the crystallization temperature is controlled to 60℃, and stirred continuously for crystallization for 10h. After the crystallization is completed, the solid-liquid separation is carried out, and the solid is washed with a mixed solution of deionized water and ethanol until neutral, and then the solid is placed in a 60℃ constant temperature box to dry for 6-12h. Weigh 1g of the above zinc-aluminum hydrotalcite, add it to 100mL of copper nitrate trihydrate solution, mix well, and stir vigorously at room temperature for 24h. After crystallization, separate the solid and liquid, and wash the solid with a mixed solution of deionized water and ethanol until it is neutral. Then place the solid in a 60℃ constant temperature oven to dry for 6-12h. Similarly, roast it at 500℃, 3℃ / min, in air atmosphere for 4h, and finally at 300℃, with a total flow rate of 100mL·min -1 , reduced in a mixed gas of H2:N2 ratio of 1:4 at 3℃ / min for 2h to obtain Cu-S6 catalyst.

[0250] In the Cu-S6 catalyst provided in this comparative example, based on the mass of the catalyst being 100%, the mass content of Cu is 10 wt%.

[0251] (ii) Cu-S6 catalyst catalyzes CO and / or CO2 hydrogenation

[0252] This method is the same as the method for catalytic hydrogenation of CO and / or CO2 provided in Example 1, the difference is that the catalyst is the Cu-S6 catalyst provided in this comparative example, and the rest is the same as Example 1.

[0253] The reaction product detection method is the same as in Example 1. The obtained CO and / or CO2 hydrogenation reaction performances are shown in Tables 1 to 3.

[0254] Example 5

[0255] (I) Preparation of Cu-S1-350 based catalyst

[0256] The preparation method is the same as that of Example 1, but the difference is that the temperature of the topological transformation treatment is 350° C., and the obtained Cu-based catalyst is marked as Cu-S1-350 catalyst.

[0257] In the Cu-S1-350 catalyst provided in this embodiment, based on the mass of the catalyst being 100%, the mass content of Cu is 10 wt%.

[0258] (ii) Cu-S1-350 catalyst catalyzes CO and / or CO2 hydrogenation

[0259] This method is the same as the method for catalytic hydrogenation of CO and / or CO2 provided in Example 1, but the difference is that the catalyst is Cu-S1-350 catalyst, and the rest is the same as Example 1.

[0260] The reaction product detection method is the same as in Example 1. The obtained CO and / or CO2 hydrogenation reaction performances are shown in Tables 1 to 3.

[0261] Example 6

[0262] (I) Preparation of Cu-S1-600 catalyst

[0263] The preparation method is the same as that of Example 1, but the difference is that the temperature of the topological transformation treatment is 600° C., and the obtained Cu-based catalyst is marked as Cu-S1-600 catalyst.

[0264] In the Cu-S1-600 catalyst provided in this embodiment, based on the mass of the catalyst being 100%, the mass content of Cu is 10 wt%.

[0265] (II) Cu-S1-600 catalyst catalyzes CO and / or CO2 hydrogenation

[0266] This method is the same as the method for catalytic hydrogenation of CO and / or CO2 provided in Example 1, but the difference is that the catalyst is Cu-S1-600 catalyst, and the rest is the same as Example 1.

[0267] The reaction product detection method is the same as in Example 1. The obtained CO and / or CO2 hydrogenation reaction performances are shown in Tables 1 to 3.

[0268] Example 7

[0269] (I) Preparation of Cu-S1-6% Catalyst

[0270] The preparation method is the same as that of Example 1, but the difference is that, based on the mass of the catalyst being 100%, the mass content of Cu is 6wt%, and the obtained Cu-based catalyst is marked as Cu-S1-6% catalyst.

[0271] (II) Cu-S1-6% catalyst for catalytic hydrogenation of carbon dioxide

[0272] This method is the same as the method for catalytic hydrogenation of carbon dioxide provided in Example 1, but the difference is that the catalyst is Cu-S1-6% catalyst, and the rest is the same as Example 1.

[0273] The reaction product detection method is the same as in Example 1. The obtained CO and / or CO2 hydrogenation reaction performances are shown in Tables 1 to 3.

[0274] Example 8

[0275] (I) Preparation of Cu-S1-18% Catalyst

[0276] The preparation method is the same as that of Example 1, but the difference is that, based on the mass of the catalyst being 100%, the mass content of Cu is 18 wt %, and the obtained Cu-based catalyst is marked as Cu-S1-18% catalyst.

[0277] (II) Cu-S1-18% catalyst for carbon dioxide hydrogenation

[0278] This method is the same as the method for catalytic hydrogenation of carbon dioxide provided in Example 1, but the difference is that the catalyst is Cu-S1-18% catalyst, and the rest is the same as Example 1.

[0279] The reaction product detection method is the same as in Example 1. The obtained CO and / or CO2 hydrogenation reaction performances are shown in Tables 1 to 3.

[0280] Example 9

[0281] (I) Preparation of Cu-S1-2 catalyst

[0282] The preparation method is the same as that of Example 1.

[0283] (II) Cu-S1-2 catalyst for carbon dioxide hydrogenation

[0284] This method is the same as the method for catalytic hydrogenation of carbon dioxide provided in Example 1, except that the reaction temperature is 220°C and the mixed gas flow rate is 200 mL·min -1 , the rest are the same as in Example 1.

[0285] The reaction product detection method is the same as in Example 1. The obtained CO and / or CO2 hydrogenation reaction performances are shown in Tables 1 to 3.

[0286] Example 10

[0287] (I) Preparation of Cu-S1-350-2 catalyst

[0288] The preparation method is the same as Example 5.

[0289] (II) Cu-S1-350-2 catalyst for carbon dioxide hydrogenation

[0290] This method is the same as the method for catalytic hydrogenation of carbon dioxide provided in Example 1, except that the reaction temperature is 220°C and the mixed gas flow rate is 200 mL·min -1 , the rest are the same as in Example 5.

[0291] The reaction product detection method is the same as in Example 1. The obtained CO and / or CO2 hydrogenation reaction performances are shown in Tables 1 to 3.

[0292] Embodiment 11

[0293] (I) Preparation of Cu-S3-30 catalyst

[0294] This method is the same as the preparation method provided in Example 1, but the difference is that the heating rate of the topological transformation treatment is 30°C / min, and the obtained Cu-based catalyst is marked as Cu-S3-30 catalyst.

[0295] (II) Cu-S3-30 catalyst for carbon dioxide hydrogenation

[0296] This method is the same as the method for catalytic hydrogenation of CO and / or CO2 provided in Example 1, but the difference is that the catalyst is Cu-S3-30 catalyst, and the rest is the same as Example 1.

[0297] The reaction product detection method is the same as in Example 1. The obtained CO and / or CO2 hydrogenation reaction performances are shown in Tables 1 to 3.

[0298] Example 12

[0299] (I) Preparation of Cu-S3-240 catalyst

[0300] The preparation method is the same as Example 3.

[0301] (II) Cu-S3-240 catalyst for carbon dioxide hydrogenation

[0302] This method is the same as the method for catalytic hydrogenation of carbon dioxide provided in Example 1, except that the reaction temperature is 240°C and the mixed gas flow rate is 200 mL·min -1 , the rest are the same as in Example 3.

[0303] The reaction product detection method is the same as that in Example 1. The obtained carbon dioxide hydrogenation reaction performance is shown in Table 1.

[0304] Embodiment 13

[0305] (I) Preparation of Cu-S3-280 catalyst

[0306] The preparation method is the same as Example 3.

[0307] (II) Cu-S3-280 catalyst for carbon dioxide hydrogenation

[0308] This method is the same as the method for catalytic hydrogenation of carbon dioxide provided in Example 1, except that the reaction temperature is 280°C and the mixed gas flow rate is 200 mL·min -1 , the rest are the same as in Example 3.

[0309] The reaction product detection method is the same as that in Example 1. The obtained carbon dioxide hydrogenation reaction performance is shown in Table 1.

[0310] Table 1

[0311]

[0312]

[0313] Table 2

[0314]

[0315] Table 3

[0316]

[0317] See Table 4, which shows the performance data of the catalyst at a temperature of 220°C, a space velocity of 72000 ml / gcat / h, and 3 MPa.

[0318] Table 4

[0319]

[0320] See Table 5, which shows the performance data of the catalyst at a temperature of 220°C, a space velocity of 80,000 mL / gcat / h, and 3 MPa.

[0321] Table 5

[0322]

[0323] Among them, carbon monoxide / carbon dioxide reaction rate = (the amount of CO / CO2 substance in the feed-the amount of CO / CO2 substance in the discharge) / (time×catalyst mass)

[0324] Carbon monoxide / carbon dioxide conversion rate = (the amount of CO / CO2 in the feed - the amount of CO / CO2 in the output) / (the amount of CO / CO2 in the feed)

[0325] Methanol selectivity = the amount of methanol in the output / (the amount of CO / CO2 in the feed - the amount of CO / CO2 in the output)

[0326] Methanol space-time yield = (amount of methanol in the output × molar mass of methanol) / (time × mass of Cu in the catalyst used).

[0327] By comparing the carbon dioxide reaction rate and the space-time yield of methanol in Table 1, it is shown that different preparation methods have different performances on the reaction of preparing methanol by hydrogenation of carbon dioxide. Among them, the hydrotalcite-derived copper-based nanocatalysts prepared by the four methods can not only effectively regulate the element composition ratio, but also control the structural topological transformation parameters, thereby obtaining a supported Cu-based catalyst with high dispersion of the active component Cu and controllable electronic properties of the metal-support interface structure. Compared with the Cu-based catalyst prepared by the impregnation method, it has higher carbon dioxide activity and methanol space-time yield, and has good stability.

[0328] By comparing the carbon monoxide conversion rate and methanol selectivity in Table 2, it is shown that different preparation methods have different performances on the reaction of preparing methanol by hydrogenation of carbon monoxide. Among them, the hydrotalcite-derived copper-based nanocatalysts prepared by the four methods can not only effectively regulate the element composition ratio, but also control the structural topological transformation parameters, thereby obtaining a supported Cu-based catalyst with high dispersion of the active component Cu and controllable electronic properties of the metal-support interface structure. Compared with the Cu-based catalyst prepared by the impregnation method, it has higher carbon monoxide activity and methanol space-time yield, and has good stability.

[0329] By comparing the carbon monoxide conversion rate, carbon dioxide conversion rate and methanol selectivity in Table 3, it is shown that different preparation methods have different performances on the hydrogenation of carbon monoxide and carbon dioxide mixed gas to produce methanol. Among them, the hydrotalcite-derived copper-based nanocatalysts prepared by the four methods can not only effectively regulate the element composition ratio, but also control the structural topological transformation parameters, thereby obtaining a supported Cu-based catalyst with high dispersion of the active component Cu and controllable electronic properties of the metal-support interface structure. Compared with the Cu-based catalyst prepared by the impregnation method, it has higher carbon monoxide conversion rate, carbon dioxide conversion rate and methanol selectivity, and has good stability.

[0330] By comparing the carbon dioxide reaction rate and methanol space-time yield at high space velocity in Tables 4 and 5, it is shown that different topological transition temperatures and Cu mass fractions have different effects on the performance of the carbon dioxide hydrogenation to methanol reaction. Among them, when the structural topological transition temperature reaches 350°C, the methanol space-time yield can reach 9021.3 mg / (g Cu h). It can be found that the space-time yield of methanol is higher at a lower Cu mass fraction.

[0331] In addition, according to the data in the three tables, it can be seen that different element ratios and preparation methods will affect the catalyst structure, and thus the hydrogenation reaction rate and methanol selectivity are slightly different. It can be seen that the design of the hydrotalcite precursor CuZnAl-based catalyst can not only effectively regulate the element composition ratio, and the structural topological transformation parameters are controllable, but also promote the CO2 adsorption activation ability by increasing the number of oxygen vacancies and alkaline sites, and can also improve the catalytic reaction performance by regulating the metal-support interaction. Therefore, a supported Cu-based catalyst with high dispersion of active component Cu and controllable metal-support interface geometry and electronic properties is obtained, which has excellent performance.

[0332] See also Figure 1 , Figure 1 The present invention provides SEM images of the hydrotalcite precursor and the hydrotalcite-derived copper-based nanocatalyst prepared by the present invention. Among them, (a1) is the SEM image of the hydrotalcite precursor of Cu-S1, (b1) is the SEM image of the hydrotalcite precursor of Cu-S1-6%, and (c1) is the SEM image of the hydrotalcite precursor of Cu-S1-18%; (a2) is the SEM image of Cu-S1 after topological transformation in air atmosphere, (b2) is the SEM image of Cu-S1-6% after topological transformation in air atmosphere, and (c2) is the SEM image of Cu-S1-18% after topological transformation in air atmosphere; (a3) ​​is the SEM image of Cu-S1 after topological transformation in hydrogen mixed atmosphere, (b3) is the SEM image of Cu-S1-6% after topological transformation in hydrogen mixed atmosphere, and (c3) is the SEM image of Cu-S1-18% after topological transformation in hydrogen mixed atmosphere.

[0333] See also Figure 2 , Figure 2 The SEM images of the hydrotalcite-derived copper-based nanocatalysts Cu-S5 and Cu-S6 prepared in the present invention are shown in Figure 1. (a) is the SEM image of Cu-S5, and (b) is the SEM image of Cu-S6.

[0334] See also Figure 3 , Figure 3 The SEM images of the hydrotalcite-derived copper-based nanocatalysts Cu-S1-350 and Cu-S1-600 provided by the present invention are shown in Figure 1. (a) is the SEM image of Cu-S1-350, and (b) is the SEM image of Cu-S1-600.

[0335] See also Figure 4 , Figure 4 This is a SEM image of the hydrotalcite-derived copper-based nanocatalyst Cu-S1-18% prepared in the present invention.

[0336] See also Figure 5 , Figure 5This is a mapping diagram of Cu, Zn and Al elements in the hydrotalcite-derived copper-based nanocatalyst Cu-S1-18% prepared in the present invention.

[0337] See also Figure 6 , Figure 6 XANES and Fourier transformed EXAFS (R space) spectra of Cu K-edge of Cu-S1-6%, Cu-S1, Cu-S1-18%, Cu foil, Cu2O and CuO. (a) is the XANES of Cu K-edge, and (b) is the Fourier transformed EXAFS (R space) spectrum.

[0338] The preparation method provided by the present invention utilizes the adjustable metal element of hydrotalcite, and after the structural topology transformation, the metal is highly dispersed and still maintains the intercalation structure, thereby realizing the microstructure regulation of Cu in the Cu-based catalyst. The Cu-based catalyst prepared by the method has good Cu dispersion, and the electronic properties of the metal-carrier interface structure are adjustable. When it is used for CO / CO2 hydrogenation reaction, it also has good catalytic hydrogenation reaction performance.

[0339] The above is a detailed introduction to a hydrotalcite-derived copper-based nanocatalyst for CO / CO2 hydrogenation to methanol provided by the present invention, and its preparation method and application. The principle and implementation mode of the present invention are described in detail using specific examples herein. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention, including the best mode, and also enables any technician in the field to practice the present invention, including manufacturing and using any device or system, and implementing any combined method. It should be pointed out that for ordinary technicians in the technical field, without departing from the principle of the present invention, the present invention can also be improved and modified in several ways, and these improvements and modifications also fall within the scope of protection of the claims of the present invention. The scope of patent protection of the present invention is defined by the claims, and may include other embodiments that can be thought of by those skilled in the art. If these other embodiments have structural elements that are not different from the textual expression of the claims, or if they include equivalent structural elements that are not substantially different from the textual expression of the claims, then these other embodiments should also be included in the scope of the claims.

Claims

1. A hydrotalcite-derived copper-based nanocatalyst, characterized in that: The hydrotalcite-derived copper-based nanocatalyst is obtained by subjecting a multi-metal hydroxide precursor having a hydrotalcite intercalation structure to a structural topological transformation treatment; The metal includes Cu, Zn and Al; The hydrotalcite-derived copper-based nanocatalyst has a nano-level layered structure.

2. The hydrotalcite-derived copper-based nanocatalyst according to claim 1, characterized in that: In the copper-based catalyst, the molar ratio of Cu to Zn is (0.1-10): (0.1-10); In the copper-based catalyst, the molar ratio of the total molar number of Cu+Zn to Al is (1-6):1; The hydrotalcite-derived copper-based nanocatalyst is a hydrogenation reaction catalyst.

3. The hydrotalcite-derived copper-based nanocatalyst according to claim 1, characterized in that: In the layered structure, the three metal cations of Cu, Zn and Al have an atomic-level arrangement structure in the cation layer; The hydrotalcite-derived copper-based nanocatalyst includes zinc hydroxide, zinc oxide, aluminum hydroxide, aluminum oxide, copper oxide and metallic copper; In the layered structure, the thickness of a single layer is 1 to 10 nm; On the layered structure, the dispersion of metal Cu is 10% to 90%; The hydrotalcite-derived copper-based nanocatalyst is a catalyst for preparing methanol by hydrogenating CO / CO2.

4. A method for preparing a hydrotalcite-derived copper-based nanocatalyst, characterized in that: The following steps are involved: 1) mixing a copper source, a zinc source, an aluminum source and a solvent to obtain a mixed solution; 2) adding a precipitant, and preparing the catalyst by a pH method, a colloid mill method, a urea-acetone method, and a hydrothermal synthesis method, washing with a mixed solution of water and ethanol, and drying to obtain a catalyst precursor of a layered double metal hydroxide; The precipitant is a hydroxide-containing alkaline compound, a carbonate, a bicarbonate, a mixed alkaline solution of a hydroxide-containing alkaline compound and a carbonate and / or bicarbonate, or urea; 3) The catalyst precursor obtained in the above step is subjected to a structural topological transformation treatment to obtain a hydrotalcite-derived copper-based nanocatalyst.

5. The preparation method according to claim 4, characterized in that: The zinc source includes one or more of zinc nitrate hexahydrate, zinc acetate and zinc chloride; The aluminum source includes one or more of aluminum nitrate nonahydrate, aluminum chloride hexahydrate, anhydrous aluminum chloride and aluminum oxide; The copper source includes one or more of copper nitrate trihydrate, copper chloride and copper acetate; The hydroxide-containing alkaline compound includes sodium hydroxide and / or potassium hydroxide; The carbonate includes sodium carbonate and / or potassium carbonate; The carbonate includes sodium bicarbonate and / or potassium bicarbonate.

6. The preparation method according to claim 5, characterized in that: The copper source and the zinc source are present in a molar ratio of (0.1-10): (0.1-10) based on the moles of copper and zinc. The molar ratio of the hydroxide-containing alkaline compound to the carbonate is (0.1-5):(0.1-5); The molar ratio of the hydroxide-containing alkaline compound to the bicarbonate is (0.1-5):(0.1-5); The molar ratio of the urea to the metal ion is (2-28):1; The volume ratio of the mixed solution of water and ethanol is (0-1):(0-1).

7. The preparation method according to claim 4, characterized in that: The specific process of the pH method comprises the following steps: 11) mixing a copper source, a zinc source, an aluminum source and water to obtain a mixed salt solution; Mixing a hydroxide-containing alkaline compound, a carbonate and water to obtain a mixed alkaline solution; 12) controlling the pH value, mixing the mixed salt solution and the mixed alkali solution obtained in the above step again, and then crystallizing them to obtain a catalyst precursor of a layered double metal hydroxide; The specific process of the colloid mill method comprises the following steps: 11') mixing a copper source, a zinc source, an aluminum source and water to obtain a mixed salt solution; Mixing a hydroxide-containing alkaline compound, a carbonate and water to obtain a mixed alkaline solution; 12') Controlling the pH value, mixing the mixed salt solution and the mixed alkali solution obtained in the above steps through a colloid mill and then crystallizing to obtain a catalyst precursor of a layered double metal hydroxide.

8. The preparation method according to claim 4, characterized in that: The specific process of the urea-acetone method comprises the following steps: 1a) mixing a copper source, a zinc source, an aluminum source, urea and water to obtain a mixed solution; 1b) crystallizing the mixed solution obtained in the above step to separate the solid phase, and then mixing the solid phase with the ethanol solution of acetone again, and washing with the ethanol solution of acetone to obtain a catalyst precursor of a layered double metal hydroxide; The specific process of the hydrothermal synthesis method comprises the following steps: 1A) mixing a copper source, a zinc source, aluminum oxide and water to obtain a mixed solution; Mixing urea and water to obtain a urea solution; 1B) The mixed solution obtained in the above step and the urea solution are mixed again for hydrothermal reaction, and then crystallized to obtain a catalyst precursor of a layered double metal hydroxide.

9. The preparation method according to claim 4, characterized in that: The topological transformation treatment is specifically, performing a reduction treatment under a certain temperature, pressure and atmosphere; The heating rate of the topological transformation treatment is 0.1 to 50°C / min; The temperature of the topological transformation treatment is 160-1000° C.; The topology transformation process takes 0.5 to 48 hours. The pressure of the topological transformation treatment is 0.1 to 10 MPa; The atmosphere includes reducing gas, a mixed gas of reducing gas and protective gas, air or different atmospheres are processed in sequence.

10. Use of the hydrotalcite-derived copper-based nanocatalyst according to any one of claims 1 to 3 or the hydrotalcite-derived copper-based nanocatalyst prepared by the preparation method according to any one of claims 4 to 9 as a catalyst in the hydrogenation of CO and / or CO2 to produce methanol.

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