A copper-based catalyst, its preparation method and use

Abstract

The application discloses a copper-based catalyst and a preparation method and application thereof. The copper-based catalyst is composed of a carrier and an active component. The carrier is a molecular sieve with a silicon-aluminum molar ratio of 1-20. The active component includes copper. The content of copper in the copper-based catalyst is 0.1-70% based on 100% of the mass of the copper-based catalyst. The copper-based catalyst is coupled with a non-equilibrium plasma. In the coupling system, carbon dioxide and methane mixed gas are reacted in one step to generate methanol. The selectivity of the obtained methanol reaches 70-95%, which is much higher than the best result 35% in the current public literature. The application solves the problem of low selectivity of methanol in reaction products in the existing plasma catalytic methane and carbon dioxide conversion technology, improves the utilization value of two greenhouse gases, and is favorable for chemical production and use.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of catalysts, and particularly relates to a copper-based catalyst, a preparation method thereof, and application of the copper-based catalyst in catalyzing one-step preparation of methanol from carbon dioxide and methane. BACKGROUND

[0002] Methane and carbon dioxide are the main greenhouse gases in the atmosphere, and are also potential "carbon resources". If they can be "turned into treasure", not only can the ecological environment problems caused by greenhouse gas emissions be alleviated, but also the sustainable recycling of carbon resources can be realized. Therefore, the research on the co-conversion of methane and carbon dioxide is of great significance to natural gas chemical industry, petroleum chemical industry and environmental protection, and has attracted widespread attention from the academic and industrial circles.

[0003] One of the ideal utilization ways of methane and carbon dioxide is to prepare methanol therefrom. Methanol is an important chemical raw material, which can be used as a gasoline additive, and can also be used to produce olefins, aromatic hydrocarbons and other chemicals through MTO, MTP and other processes. At present, the conventional catalytic method for converting methane and carbon dioxide into methanol requires a two-step process and high temperature and high pressure conditions, which is energy-intensive and complex. The first step is to reform methane and carbon dioxide into synthesis gas (CH4+CO2→2CO+2H2, ΔH298K=247 kJ / mol) under high temperature conditions, and the second step is to convert the obtained synthesis gas into methanol (CO+2H2→CH3OH) under high pressure conditions. In the first step, due to the extremely high thermodynamic stability of methane and carbon dioxide, the reforming process usually requires a high temperature of 1100-1200K. The high temperature condition is harsh for the device, and is prone to cause carbon deposition, reduce carbon utilization, and also cause the catalyst to be deactivated due to sintering and carbon deposition, thereby reducing the stability of the catalyst. In the second step, since the synthesis gas to methanol is a molecular number reduction reaction, the reaction needs to be synthesized under high pressure conditions. The high pressure condition is also harsh for the device, and is difficult to operate in practice, and has high energy consumption. Obviously, the operation investment, equipment investment and equipment maintenance cost of the two-step method for converting methane and carbon dioxide into methanol are high.

[0004] Non-equilibrium plasma technology has been widely used in the low-temperature activation and conversion of methane and carbon dioxide. Recent studies have found that when non-equilibrium plasma is coupled with some catalysts (plasma catalysis technology), carbon dioxide and methane can be converted into high-value liquid chemicals in one step, breaking through the above two-step high temperature and high pressure process. However, the liquid chemicals obtained by one-step process are complex, mainly composed of acids, alcohols, ketones, aldehydes and the like, in addition to carbon monoxide and hydrocarbon gas products.

[0005] As disclosed in Chinese patent document CN113559836A, a kind of high-efficiency supported bimetallic catalyst and preparation method and application, by combining medium barrier discharge plasma technology with solution combustion method, form micro combustion method to prepare supported bimetallic catalyst.The technical features are as follows:Firstly, dissolve bimetallic components in solvent, add fuel to obtain precursor solution, load precursor on carrier, and dry after standing;Then the dried product is ground and subjected to intermittent medium barrier discharge treatment;Then the product obtained after discharge treatment is calcined to obtain high-efficiency supported bimetallic catalyst.Secondly, the bimetallic components are two of Ni salt, Fe salt, Co salt, Cu salt, Zn salt, Ce salt, Zr salt, Mg salt and La salt;The carrier is one of SiO2, α-Al2O3, β-Al2O3, γ-Al2O3 and ZSM-5;The fuel is one of urea, citric acid, glycine, ethylene glycol, ethanol, glycerol and n-propanol.Thirdly, the intermittent medium barrier discharge treatment is that the voltage of plasma generator is 50-150V, the current is 2-3A, the discharge times is 20-40 times, and the discharge time of each time is 3min.Fourthly, the calcination temperature is 300-800℃, and the time is 2-5h.Fifthly, the application of high-efficiency supported bimetallic catalyst in methane dry reforming;Specifically, dilute high-efficiency supported bimetallic catalyst with quartz sand and put it into a quartz tube, then install the quartz tube in a fixed bed reactor, and introduce raw gas into the fixed bed reactor to carry out methane dry reforming reaction at normal pressure;Wherein, the flow rate of raw gas is 40-45mL / min, the space velocity is 48000-54000mL / (g.h), the reaction temperature is 450-850℃, and the raw gas is a mixture of CO2, CH4 and Ar.The defects or deficiencies of this technical solution are as follows:(1) In the process of catalyst preparation, fuel is added, and catalyst is prepared by combining medium barrier discharge plasma technology with solution combustion method, i.e. additional fuel is introduced in the process of catalyst preparation, the process is complex, and the cost is increased, even without fuel, the dried catalyst precursor can be directly treated by medium barrier discharge plasma.(2) The dried catalyst precursor is treated by medium barrier discharge plasma, and the catalyst product is not obtained directly, and further heat calcination treatment is needed to obtain the final supported bimetallic catalyst.(3) When the dried catalyst precursor is treated by medium barrier discharge plasma, intermittent discharge treatment method is adopted, which requires 20-40 times of discharge treatment, the operation process is complex, and the voltage and current of plasma generator are high, which are 50-150V and 2-3A respectively.(4) The prepared catalyst requires a bimetallic composition, and the carrier is one of SiO2, a-Al2O3, b-Al2O3, g-Al2O3 and ZSM-5. The catalyst provided in the examples mainly consists of Ni, and other metals are compounded with Ni. Ni is easy to form a "nickel aluminum spinel" with the Al2O3 carrier. In addition, nickel-based catalysts are recognized as the best catalysts for the dry reforming of methane and carbon dioxide to produce synthesis gas (CO and H2), but are not suitable for the preparation of high-value alcohol products. (5) The raw gas is a mixture of CO2, CH4 and Ar, the reaction temperature is 450-850℃, the reaction is a single thermal catalytic reaction and the reaction temperature is high, and the obtained reaction product is synthesis gas. High reaction temperature cannot obtain high-value alcohol products.

[0006] Applied Catalysis B: Environmental, 2020, 261, 118228 reported a catalyst for the plasma catalytic conversion of carbon dioxide and methane into liquid products. Specifically, it is to convert carbon dioxide and methane into liquid products in one step by coupling non-equilibrium plasma and catalysts. The non-equilibrium plasma involved is generated by dielectric barrier discharge, and the electric heat generated during the discharge process is removed in time by a compressed air gun to achieve the purpose of generating liquid products. The catalysts involved include SiO2 supported Fe or Co supported catalysts, which are prepared by impregnation method, and the catalysts are pretreated by reduction with H2 / N2 (5% / 95%) mixed gas at 600℃ for 10h before use. The defects or deficiencies of this technical scheme are that the total selectivity of the liquid product obtained by reaction is low, and the highest is only 47.9%. Although Fe / SiO2 is more conducive to the generation of alcohols (methanol and ethanol) than Co / SiO2, the highest selectivity of methanol obtained is only 31%.

[0007] Angewandte Chemie International Edition, 2017, 56, 13679 reported a method of plasma catalysis of carbon dioxide and methane to high value-added fuels and chemicals, specifically: using non-equilibrium plasma or non-equilibrium plasma coupled with catalyst means, under the condition of normal temperature and pressure, carbon dioxide and methane are converted into high value-added fuels and chemicals in one step. The non-equilibrium plasma involved is generated by dielectric barrier discharge, and provides a new type of dielectric barrier discharge plasma reactor, specifically the discharge reactor is a wire-in-sleeve reactor, the inner cylinder is the reaction zone, the outer cylinder is connected with circulating water, the circulating water withdraws the discharge reaction heat in time and controls the reaction temperature, and also serves as the double role of discharge grounding electrode, to achieve the purpose of generating liquid products; the center electrode is a stainless steel rod. The catalysts involved are Cu / γ-Al2O3, Au / γ-Al2O3 and Pt / γ-Al2O3 three kinds of catalysts; The defects or deficiencies of this technical solution are: the liquid products obtained by the reaction are composed of acetic acid, methanol, ethanol, formaldehyde and acetone; the total selectivity of the liquid product is at most 59.1%, and acetic acid is the main product; In addition, the literature mentions that the Cu / γ-Al2O3, Au / γ-Al2O3 or Pt / γ-Al2O3 catalyst is filled in the plasma reactor, which leads to low methanol selectivity, and the highest methanol selectivity obtained is only 11.9%.

[0008] Journal of CO2 Utilization, 2021, 52, 101675 reported a Ni-based catalyst for plasma catalysis of carbon dioxide and methane to liquid products, specifically: using non-equilibrium plasma and Ni catalyst coupling to convert carbon dioxide and methane into liquid products in one step. The non-equilibrium plasma involved is generated by nanosecond pulse discharge; The Ni-based catalyst involved is prepared by impregnation method; The defects or deficiencies of this technical solution are: the liquid products obtained by the reaction are composed of methanol, ethanol, ethylene glycol and propanol; NiAl-LDH / NF catalyst is beneficial to the generation of methanol, but the corresponding methanol selectivity is at most only 12.3%.

[0009] Energy Conversion and Management, 2019, 191, 93 reported a catalyst for converting carbon dioxide and methane into liquid products by plasma catalysis, specifically, carbon dioxide and methane were converted into liquid products in one step by coupling non-equilibrium plasma and catalyst under the condition of introducing Ar into the mixed gas of carbon dioxide and methane. The non-equilibrium plasma was generated by dielectric barrier discharge; the catalyst was a CZSM-5 supported Pt, Ag, Pd, Re or Ir catalyst, which was prepared by impregnation method; the technical scheme has defects or deficiencies in that the total selectivity of the liquid product corresponding to the Pt / CZSM-5 catalyst is at most 60%, and the liquid product obtained by the reaction includes formaldehyde, methanol, ethanol and acetone, but the selectivity of each product is not given.

[0010] Chinese patent document CN109603707A discloses a device for synthesizing C1-C4 alcohol from CH4 / CO2 at low temperature and a synthesis method thereof, specifically, the device is a discharge reactor composed of three parallel metal plates, and the upper and lower two metal plates are linked with a refrigeration unit; the synthesis method is to convert methane and carbon dioxide into C1-C4 alcohol under the joint action of the device, a supported catalyst and an additive gas; the support of the supported catalyst is a metal oxide support (Al2O3, ZnO, TiO2, SiO2, NbO, CeO2), a molecular sieve support (ZSM-5, TS-1, SAPO-34, β, MCM-41), a carbon material support (activated carbon, carbon fiber, graphene, carbon nanotube), a molybdenum carbide support, an iron carbide support, a molybdenum nitride support, an iron nitride support or a cobalt nitride support; the technical scheme has defects or deficiencies in that the obtained alcohol is complex and is composed of methanol, ethanol, propanol and butanol, which increases the difficulty of separating methanol from the mixed alcohol; the total selectivity of the mixed alcohol is at most 68%, but the selectivity of methanol is not given.

[0011] In summary, the existing plasma catalytic one-step conversion of carbon dioxide and methane into liquid chemicals generally has the problems of low selectivity of liquid products and complex composition of liquid products, and low selectivity of methanol. SUMMARY

[0012] The technical problem to be solved by the present application is to provide a preparation method and application of a copper-based catalyst, which can convert methane and carbon dioxide into methanol in one step and with high selectivity, thereby improving the utilization value of the two greenhouse gases and being beneficial to chemical production and use.

[0013] To this end, the present application provides the following technical scheme:

[0014] A copper-based catalyst, which is composed of a carrier and an active component, the carrier is a molecular sieve with a silicon-aluminum molar ratio of 1-20, and the active component includes copper.

[0015] The content of copper in the copper-based catalyst is 0.1% to 70% based on the mass of the copper-based catalyst.

[0016] The content of copper in the specific catalyst can be selected according to actual needs in combination with other factors, and is, for example, 0.5%, 1.0%, 5%, 8%, 15%, 35%, 45%, 40%, 55%, 60%, 65%, etc.

[0017] Optionally, the carrier is a molecular sieve with a silicon-aluminum molar ratio of 1 to 10.

[0018] The low-silicon-aluminum-ratio molecular sieve used in the present application is preferably a molecular sieve from which a template has been removed after calcination, and can be a molecular sieve modified by exchange with an alkali metal, an alkaline earth metal, a rare earth metal, or an ammonium salt. Preferably, the molecular sieve is one or more of X-type molecular sieves and Y-type molecular sieves.

[0019] Optionally, the content of copper in the copper-based catalyst is 5% to 50%, preferably 5% to 30%, for example 10%, 15%, 20%, 25%, 22%, 18%, etc., based on the mass of the copper-based catalyst.

[0020] Optionally, the active component further contains one or more of IA, IIA, VIIIB, IIB, and lanthanide series metals.

[0021] Optionally, the molar ratio of copper to other active components other than copper in the active component is 2 to 8.

[0022] Preferably, the modifier is at least one of zinc, sodium, potassium, rubidium, cesium, lithium, beryllium, magnesium, calcium, strontium, barium, cerium, nickel, cobalt, and iron.

[0023] The present application also provides a preparation method of the above-mentioned copper-based catalyst, comprising the following steps:

[0024] Mixing a carrier (a molecular sieve with a silicon-aluminum ratio of 1 to 20) with a solution containing a copper-containing precursor, drying, to obtain a precursor of the copper-based catalyst;

[0025] Carrying out aerobic calcination on the precursor of the copper-based catalyst, to obtain the copper-based catalyst.

[0026] Optionally, the aerobic calcination is non-equilibrium plasma calcination or thermal calcination.

[0027] Optionally, the atmosphere for the non-equilibrium plasma calcination is pure oxygen or a mixed gas of oxygen and an inert gas, and the inert gas is at least one of nitrogen, argon, and helium.

[0028] Optionally, the thermal calcination can be conventional thermal calcination, such as calcination at 400-550℃ for 3-5h.

[0029] Optionally, the non-equilibrium plasma working gas calcination is at 200-400℃ for 0.5-3h.

[0030] The present application is also not limited to the form of mixing the solution of copper-containing precursor with the carrier (molecular sieve), such as conventional impregnation, deposition precipitation, loading, precipitation, etc. The carrier of the present application is a low silica-alumina ratio molecular sieve, which can not be particularly limited in type, but must require that the silica-alumina molar ratio in the molecular sieve be less than 20, more preferably less than 10. Only the low silica-alumina ratio molecular sieve and the copper active component plus oxygen calcination can make the copper species more uniformly dispersed under the condition of high copper content.

[0031] Preferably, the carrier (molecular sieve with a silica-alumina ratio of 1-20) is impure before being mixed with the solution of copper-containing precursor, which can be impure by conventional methods, such as calcination.

[0032] Non-equilibrium plasma discharge calcination generally refers to the unique nature of using non-equilibrium plasma rich in high-energy particles, charged particles, ultraviolet light, etc., and its heavy particle temperature is low, and the free electron temperature is high (Te≈10 4 -10 5 K≈1-10eV) to calcine the precursor of the copper-based catalyst.

[0033] Preferably, the form of non-equilibrium plasma discharge is sinusoidal alternating current, and the discharge frequency is 6-20kHz.

[0034] In the present application, the non-equilibrium plasma discharge calcination process can be more specifically as follows: the dry copper-based catalyst precursor powder is formed into granules, then placed into a dielectric barrier discharge reactor, and the working gas is continuously flowed through the discharge reactor. Under a pressure of 0.01-0.1MPa, a sinusoidal alternating voltage is applied between the high-voltage electrode and the grounded electrode of the discharge reactor. When the power input reaches a certain threshold, such as the electric field reaching the ionization threshold of the working gas, the working gas molecules are broken down to form plasma. The copper-based catalyst precursor is then treated in the plasma atmosphere for 0.5-3h to obtain a copper-based catalyst.

[0035] Optionally, the copper precursor can be selected from at least one of nitrate, nitrate, acetate, oxalate, sulfate, and chloride, etc. water-soluble copper salt.

[0036] The present application also provides a copper-based catalyst prepared by the above-mentioned method for use in the one-step preparation of methanol from carbon dioxide and methane.

[0037] Optionally, the application method comprises the following steps: introducing a mixed gas of carbon dioxide and methane into the dielectric barrier discharge reactor containing the copper-based catalyst, and then reacting at 100-300 ℃ to obtain methanol in one step; wherein the molar ratio of methane to carbon dioxide is 0.5-5.

[0038] Preferably, the reaction temperature is 150-250 ℃.

[0039] Optionally, the dielectric barrier discharge reactor comprises an insulating medium, a high-voltage electrode and a low-voltage electrode, the insulating medium is located between the high-voltage electrode and the low-voltage electrode, and the catalyst is filled in the non-equilibrium plasma discharge space.

[0040] The present application does not particularly limit the type of the dielectric barrier discharge plasma reactor, which can be a wire-cylinder electrode structure, a needle-plate electrode structure, a tube-plate electrode structure, a tube-tube electrode structure or a plate-plate electrode structure, and the discharge barrier medium layer is not particularly limited, which can be a glass layer, a quartz layer, a mica layer or an organic glass layer, etc.

[0041] Since the copper-based catalyst of the present application is selected in the process of high-selectivity one-step preparation of methanol from a mixed gas of carbon dioxide and methane, it is necessary to avoid excessive reaction in order to achieve high selectivity of methanol, and thus it is desirable to control the reaction to be relatively mild. The inventors have also unexpectedly found that the introduction of water vapor under such mild conditions can achieve better results. In the reaction process, the water vapor has two main functions: on the one hand, water vapor acts as an extractant to protect the target product methanol, which is easily soluble in water, and by using water vapor, methanol is promptly desorbed from the catalyst surface, preventing the further reaction of methanol on the catalyst surface to generate CO and other by-products, thereby improving the selectivity of methanol; on the other hand, water vapor promotes the oxidation of methane to generate alcohols, and water molecules in the plasma region can generate OH species, which not only promotes the dissociation of CH4 to generate CH3 species, but also directly reacts with CH3 to generate methanol, thereby improving the selectivity of methanol.

[0042] Preferably, the mixed gas of carbon dioxide and methane further contains water vapor, wherein the volume fraction of the water vapor in the mixed gas is 5%-70%, preferably 20%-50%.

[0043] The method for introducing water vapor in the present application is not limited, for example, water vapor can be introduced into the dielectric barrier discharge reactor alone, or water vapor can be mixed with the reaction raw material gas (methane and carbon dioxide) and then introduced into the dielectric barrier discharge reactor. When water vapor is obtained by flowing the reaction raw material gas through a bubbler containing liquid water, circulating water is introduced between the inner and outer glass tubes of the bubbler, and the saturation vapor pressure of water vapor in the bubbler is controlled by the temperature of the circulating water, thereby controlling the volume fraction of water vapor in the mixed gas.

[0044] Compared with the prior art, the technical scheme of the present application has the following beneficial effects:

[0045] 1. The composition of the liquid chemicals obtained by the prior art using methane and carbon dioxide as raw materials through a one-step process is complex, mainly composed of acids, alcohols, ketones, aldehydes, etc., in addition to carbon monoxide and hydrocarbon gas phase products. This is the most major problem currently faced by the one-step conversion of carbon dioxide and methane into high-value liquid chemicals by plasma catalysis, and the key factor to solve this problem is the catalyst. Due to the difficulty and the fact that the research on the one-step conversion of carbon dioxide and methane into high-value liquid chemicals by plasma catalysis is still in its infancy, the active sites of the catalyst in the existing research are not clear, and the research on the catalyst is in the trial-and-error stage.

[0046] The copper-based catalyst provided by the present application uses copper as the main active component and combines with a molecular sieve carrier with a low silicon-aluminum ratio. When used for catalyzing the one-step conversion of methane and carbon dioxide, the catalyst has high selectivity for methanol, and the selectivity of methanol reaches more than 70%.

[0047] 2. The inventors have found through research that the catalyst prepared by using a non-equilibrium plasma to calcine the precursor of the copper-based catalyst with copper as the main active component and a molecular sieve with a low silicon-aluminum ratio as the carrier has better methanol selectivity. The main reasons may be as follows: first, the molecular sieve with a low silicon-aluminum ratio has a large number of positively charged aluminum ions, which makes the molecular sieve channel have a strong electrostatic field, easily adsorbing polar molecules, making the molecular sieve with a low silicon-aluminum ratio have strong hydrophilicity, and further causing the copper precursor solution to be quickly and massively adsorbed in the molecular sieve channel; second, the precursor of the copper-based catalyst is calcined by using a non-equilibrium plasma, which has the unique characteristics of being rich in high-energy particles, charged particles, ultraviolet rays, etc., and having a low temperature of heavy particles and a high temperature of free electrons (Te≈10 4 -10 5 K≈1-10eV), mainly by colliding the high-energy particles in the plasma zone to activate the copper-based catalyst precursor, to achieve the purpose of calcining the catalyst precursor, so that the active component copper can be uniformly dispersed in the carrier; third, the non-equilibrium plasma zone is rich in high-concentration free electrons, which can adhere to the surface of the catalyst particles, so that the catalyst particles repel each other due to the same charge, further improving the uniform dispersion of the low active component copper.

[0048] 3. The application of the copper-based catalyst provided by this invention, by coupling the copper-based catalyst with non-equilibrium plasma, allows for the one-step reaction of a mixture of carbon dioxide and methane in this coupled system. This effectively controls the distribution of reaction products and significantly improves the selectivity of methanol, the target product, in the reaction products. The methanol selectivity obtained reaches 70-95%, which is far higher than the best result of 35% in the current published literature. This solves the problem of low methanol selectivity in the reaction products faced by existing plasma-catalyzed methane and carbon dioxide conversion technologies, improves the utilization value of the two greenhouse gases, and is beneficial to chemical production and use. Detailed Implementation

[0049] The present invention will now be described in detail through embodiments. It should be noted that the following embodiments are only for further illustration of the present invention and should not be construed as limiting the scope of protection of the present invention. Those skilled in the art can make some non-essential improvements and adjustments to the present invention based on the above description.

[0050] For any experimental steps or conditions not specified in the examples and comparative examples, the procedures or conditions described in the literature in this field can be followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0051] For ease of comparison, the plasma catalytic reactors used below are all cylindrical dielectric barrier discharge quartz reactors; the purity of methane and carbon dioxide gases is 99%; the non-equilibrium plasma discharge gap is 3 mm, the discharge form is sinusoidal alternating current, and a copper-based catalyst is filled in the reactor discharge zone; the reaction temperature is controlled by coupling the discharge power of the non-equilibrium plasma with external heating; the mixed gas flow of methane and carbon dioxide passes through the plasma catalytic reaction discharge zone, and the reaction products flow through a cold trap (a mixture of liquid nitrogen and isopropanol) collector and are separated into gas and liquid phases. The gas phase substances are analyzed by online Shimadzu chromatography, and the liquid phase products are collected and analyzed by Shimadzu GC-2014 chromatography. For water vapor, water vapor is obtained by passing a mixed gas flow of methane and carbon dioxide through a bubbler containing liquid water. Circulating water at a certain temperature is introduced between the inner and outer glass tubes of the bubbler, and this circulating water is used to control the saturated vapor pressure of the water vapor inside the bubbler.

[0052] Example 1

[0053] Catalyst preparation: Commercially available 13X zeolite with a silicon-aluminum molar ratio of 2 was first calcined at 400℃ for 5 hours to remove impurities, and 13X powder was obtained for later use.

[0054] A copper precursor, Cu(N03)2-3H20, was dissolved in deionized water to obtain a copper nitrate solution. Then, the 13X powder was added into the copper nitrate solution under stirring and stirred for 2 h. The filter cake was dried at 120 °C overnight and calcined in air at 540 °C for 3 h to obtain a copper theoretical content of 20 wt% Cu / 13X catalyst.

[0055] Example 2

[0056] Catalyst preparation: The catalyst was prepared in the same way as in Example 1, except that the support was different. In this example, a 13X zeolite with a molar ratio of silica to alumina of 10 was used.

[0057] Example 3

[0058] Catalyst preparation: The catalyst was prepared in the same way as in Example 1, except that the support was different. In this example, a 13X zeolite with a molar ratio of silica to alumina of 20 was used.

[0059] Example 4

[0060] Catalyst preparation: The catalyst was prepared in the same way as in Example 1, except that the content of the active component copper was different. In this example, the theoretical content of copper in the catalyst prepared was 0.1 wt%.

[0061] Example 5

[0062] Catalyst preparation: The catalyst was prepared in the same way as in Example 1, except that the content of the active component copper was different. In this example, the theoretical content of copper in the catalyst prepared was 5 wt%.

[0063] Example 6

[0064] Catalyst preparation: The catalyst was prepared in the same way as in Example 1, except that the content of the active component copper was different. In this example, the theoretical content of copper in the catalyst prepared was 50 wt%.

[0065] Example 7

[0066] Catalyst preparation: The catalyst was prepared in the same way as in Example 1, except that the content of the active component copper was different. In this example, the theoretical content of copper in the catalyst prepared was 70 wt%.

[0067] Example 8

[0068] Catalyst preparation: The catalyst was prepared in the same way as in Example 1, except that the temperature of air calcination was different. In this example, the temperature of air calcination was 400 °C.

[0069] Example 9

[0070] Catalyst preparation: The catalyst was prepared in the same way as in Example 1, except that the calcination of the catalyst was different. Specifically, the filter cake was dried overnight at 120 °C and calcined in an oxygen non-equilibrium plasma atmosphere for 3 h, while the calcination temperature was controlled at about 200 °C by adjusting the input power of the discharge, to obtain a Cu / 13X catalyst with a theoretical Cu content of 20 wt%.

[0071] Example 10

[0072] Catalyst preparation: The catalyst was prepared in the same way as in Example 9, except that the calcination temperature and time of the catalyst were different. Specifically, the calcination temperature was controlled at about 400 °C by adjusting the input power of the discharge, and the calcination was performed for 0.5 h, to obtain a Cu / 13X catalyst with a theoretical Cu content of 20 wt%.

[0073] Example 11

[0074] Catalyst preparation: The catalyst was prepared in the same way as in Example 10, except that the calcination atmosphere of the catalyst was different. Specifically, the non-equilibrium plasma calcination atmosphere used in this example was a mixture of N2and O2at a volume ratio of 1:1, to obtain a Cu / 13X catalyst with a theoretical Cu content of 20 wt%.

[0075] Example 12

[0076] Catalyst preparation: The catalyst was prepared in the same way as in Example 10, except that the copper salt was different. Specifically, copper sulfate was used in this example, to obtain a Cu / 13X catalyst with a theoretical Cu content of 20 wt%.

[0077] Example 13

[0078] Catalyst preparation: The catalyst was prepared in the same way as in Example 10, except that the copper salt was different. Specifically, copper chloride was used in this example, to obtain a Cu / 13X catalyst with a theoretical Cu content of 20 wt%.

[0079] Example 14

[0080] Catalyst preparation: The catalyst was prepared in the same way as in Example 10, except that the carrier was different. Specifically, a commercially available Y molecular sieve with a Si / Al ratio of 2 was used in this example, to obtain a Cu / Y catalyst with a theoretical Cu content of 20 wt%.

[0081] Example 15

[0082] Catalyst preparation: The catalyst was prepared in the same way as in Example 10, except that the support was different. In this example, commercially available A zeolite with a silica-alumina ratio of 2 was used to obtain a Cu / A catalyst with a theoretical Cu content of 20 wt%.

[0083] Example 16

[0084] Catalyst preparation: The catalyst was prepared in the same way as in Example 10, except that the active component solution was different. In this example, a mixed solution was prepared by dissolving Cu(NO3)2-3H2O, a copper precursor, and zinc nitrate in deionized water to obtain a CuZnOx / 13X catalyst with a theoretical Cu content of 20 wt% and a Cu / Zn molar ratio of 2:1.

[0085] Example 17

[0086] Catalyst preparation: The catalyst was prepared in the same way as in Example 10, except that the active component solution was different. In this example, a mixed solution was prepared by dissolving Cu(NO3)2-3H2O, a copper precursor, and barium nitrate in deionized water to obtain a CuBaOx / 13X catalyst with a theoretical Cu content of 20 wt% and a Cu / Ba molar ratio of 4:1.

[0087] Example 18

[0088] Catalyst preparation: The catalyst was prepared in the same way as in Example 10, except that the active component solution was different. In this example, a mixed solution was prepared by dissolving Cu(NO3)2-3H2O, a copper precursor, and cerium nitrate in deionized water to obtain a CuCeOx / 13X catalyst with a theoretical Cu content of 20 wt% and a Cu / Ce molar ratio of 8:1.

[0089] Example 19

[0090] Catalyst preparation: The catalyst was prepared in the same way as in Example 9, except that the active component solution was different. In this example, a mixed solution was prepared by dissolving Cu(NO3)2-3H2O, a copper precursor, and iron nitrate in deionized water to obtain a CuFeOx / 13X catalyst with a theoretical Cu content of 20 wt% and a Cu / Fe molar ratio of 4:1.

[0091] Example 20

[0092] Catalyst preparation: The catalyst was prepared in the same way as in Example 1, except that the support was different. In this example, a commercially available β zeolite with a Si / Al ratio of 30 was used to obtain a Cu / β catalyst with a theoretical Cu content of 20 wt%.

[0093] Comparative Example 1

[0094] Catalyst preparation: The catalyst was prepared in the same way as in Example 1, except that the support was different. In this example, a commercially available β zeolite with a Si / Al ratio of 30 was used to obtain a Cu / β catalyst with a theoretical Cu content of 20 wt%.

[0095] Comparative Example 2

[0096] Catalyst preparation: The catalyst was prepared in the same way as in Example 1, except that the support was different. In this example, a commercially available TiO2 support was used to obtain a Cu / TiO2 catalyst with a theoretical Cu content of 20 wt%.

[0097] Comparative Example 3

[0098] Catalyst preparation: The catalyst was prepared in the same way as in Example 1, except that the content of the active component Cu was different. In this example, a catalyst with a theoretical Cu content of 90 wt% was prepared.

[0099] Comparative Example 4

[0100] Catalyst preparation: The catalyst was prepared in the same way as in Example 10, except that the calcination atmosphere was different. In this example, the non-equilibrium plasma calcination atmosphere was hydrogen, and a Cu / 13X catalyst with a theoretical Cu content of 20 wt% was obtained.

[0101] Application Example 1

[0102] The catalyst prepared in Example 1 was used in conjunction with a non-equilibrium plasma to convert methane and carbon dioxide into methanol in one step. Specifically, the non-equilibrium plasma catalytic reaction temperature was 200°C, the molar ratio of CH4 to CO2 was 2:1, and the residence time of the methane and carbon dioxide mixture in the plasma catalytic discharge space was 2.8 s.

[0103] Reaction results: Methanol selectivity was 86.0%, CH4 conversion was 24.3%, and CO2 conversion was 24.6%.

[0104] Application Example 2

[0105] Similar to the application example 1, the only difference is that the synergistic effect of the catalyst prepared in the example 2 and the non-equilibrium plasma is utilized.

[0106] Reaction results: methanol selectivity 80.3%, CH4conversion 25.5%, CO2conversion 26.8%.

[0107] Application example 3

[0108] Similar to the application example 1, the only difference is that the synergistic effect of the catalyst prepared in the example 3 and the non-equilibrium plasma is utilized.

[0109] Reaction results: methanol selectivity 70.5%, CH4conversion 27.8%, CO2conversion 29.0%.

[0110] Application example 4

[0111] Similar to the application example 1, the only difference is that the synergistic effect of the catalyst prepared in the example 4 and the non-equilibrium plasma is utilized.

[0112] Reaction results: methanol selectivity 71.0%, CH4conversion 26.5%, CO2conversion 28.6%.

[0113] Application example 5

[0114] Similar to the application example 1, the only difference is that the synergistic effect of the catalyst prepared in the example 5 and the non-equilibrium plasma is utilized.

[0115] Reaction results: methanol selectivity 80.3%, CH4conversion 30.0%, CO2conversion 33.3%.

[0116] Application example 6

[0117] Similar to the application example 1, the only difference is that the synergistic effect of the catalyst prepared in the example 6 and the non-equilibrium plasma is utilized.

[0118] Reaction results: methanol selectivity 75.5%, CH4conversion 28.4%, CO2conversion 32.2%.

[0119] Application example 7

[0120] Similar to the application example 1, the only difference is that the synergistic effect of the catalyst prepared in the example 7 and the non-equilibrium plasma is utilized.

[0121] Reaction results: methanol selectivity 71.0%, CH4conversion 31.2%, CO2conversion 33.8%.

[0122] Application example 8

[0123] Similar to the application example 1, except that the synergistic effect of the catalyst prepared in Example 8 and the non-equilibrium plasma was utilized.

[0124] Reaction results: methanol selectivity 79.8%, CH4conversion 22.3%, CO2conversion 28.4%.

[0125] Methanol selectivity 86.0%, CH4conversion 24.3%, CO2conversion 24.6%

[0126] Application Example 9

[0127] Similar to the application example 1, except that the synergistic effect of the catalyst prepared in Example 9 and the non-equilibrium plasma was utilized.

[0128] Reaction results: methanol selectivity 88.5%, CH4conversion 31.1%, CO2conversion 34.5%.

[0129] Application Example 10

[0130] Similar to the application example 1, except that the synergistic effect of the catalyst prepared in Example 10 and the non-equilibrium plasma was utilized.

[0131] Reaction results: methanol selectivity 89.7%, CH4conversion 32.5%, CO2conversion 35.7%.

[0132] Application Example 11

[0133] Similar to the application example 1, except that the synergistic effect of the catalyst prepared in Example 11 and the non-equilibrium plasma was utilized.

[0134] Reaction results: methanol selectivity 92.9.%, CH4conversion 29.6%, CO2conversion 34.5%.

[0135] Application Example 12

[0136] Similar to the application example 1, except that the synergistic effect of the catalyst prepared in Example 12 and the non-equilibrium plasma was utilized.

[0137] Reaction results: methanol selectivity 86.3%, CH4conversion 27.4%, CO2conversion 34.0%.

[0138] Application Example 13

[0139] Similar to the application example 1, except that the synergistic effect of the catalyst prepared in Example 13 and the non-equilibrium plasma was utilized.

[0140] Reaction results: methanol selectivity 84.8%, CH4conversion 28.9%, CO2conversion 32.0%.

[0141] Application Example 14

[0142] Similar to Application Example 1, except that the catalyst prepared in Example 14 was used in conjunction with the non-equilibrium plasma.

[0143] Reaction results: methanol selectivity 89.5%, CH4conversion 30.6%, CO2conversion 37.0%.

[0144] Application Example 15

[0145] Similar to Application Example 1, except that the catalyst prepared in Example 15 was used in conjunction with the non-equilibrium plasma.

[0146] Reaction results: methanol selectivity 78.7%, CH4conversion 29.0%, CO2conversion 34.5%.

[0147] Application Example 16

[0148] Similar to Application Example 1, except that the catalyst prepared in Example 16 was used in conjunction with the non-equilibrium plasma, and the non-equilibrium plasma catalytic reaction temperature was 300°C, and the CH4and CO2molar ratio was 5:1.

[0149] Reaction results: methanol selectivity 84.0%, CH4conversion 38.6%, CO2conversion 44.5%.

[0150] Application Example 17

[0151] Similar to Application Example 1, except that the catalyst prepared in Example 17 was used in conjunction with the non-equilibrium plasma, and the non-equilibrium plasma catalytic reaction temperature was 100°C, and the residence time of the CH4and CO2mixture in the plasma catalytic discharge space was 5 s.

[0152] Reaction results: methanol selectivity 80.3%, CH4conversion 37.5%, CO2conversion 24.6%.

[0153] Application Example 18

[0154] Similar to Application Example 1, except that the catalyst prepared in Example 18 was used in conjunction with the non-equilibrium plasma, and the non-equilibrium plasma catalytic reaction temperature was 150°C, and the CH4and CO2molar ratio was 1:2, and the residence time of the CH4and CO2mixture in the plasma catalytic discharge space was 10 s.

[0155] Reaction results: methanol selectivity 70.3%, CH4conversion 39.0%, CO2conversion 27.5%.

[0156] Application Example 19

[0157] Similar to Application Example 1, except that the synergistic effect of the catalyst prepared in Example 19 and non-equilibrium plasma was used, the non-equilibrium plasma catalytic reaction temperature was 100°C, and the residence time of the methane and carbon dioxide mixture in the plasma catalytic discharge space was 1 s.

[0158] Reaction results: methanol selectivity 85.3%, CH4conversion 32.1%, CO2conversion 44.9%.

[0159] Application Example 20

[0160] Similar to Application Example 1, except that the synergistic effect of the catalyst prepared in Example 20 and non-equilibrium plasma was used.

[0161] Reaction results: methanol selectivity 90.4%, CH4conversion 29.3%, CO2conversion 34.4%.

[0162] Application Example 21

[0163] Similar to Application Example 10, except that water vapor was introduced into the plasma catalytic reaction system, and the volume ratio of water vapor to the methane, carbon dioxide, and water vapor mixture was 5%.

[0164] Reaction results: methanol selectivity 91.2%, CH4conversion 36.9%, CO2conversion 20.1%.

[0165] Application Example 22

[0166] Similar to Application Example 10, except that water vapor was introduced into the plasma catalytic reaction system, and the volume ratio of water vapor to the methane, carbon dioxide, and water vapor mixture was 30%.

[0167] Reaction results: methanol selectivity 96.0%, CH4conversion 44.5%, CO2conversion 18.4%.

[0168] Application Example 23

[0169] Similar to Application Example 10, except that water vapor was introduced into the plasma catalytic reaction system, and the volume ratio of water vapor to the methane, carbon dioxide, and water vapor mixture was 70%.

[0170] Reaction results: methanol selectivity 92%, CH4conversion 35.6%, CO2conversion 18.9%.

[0171] Application Comparative Example 1

[0172] Similar to Application Example 1, except that the catalyst prepared in Application Comparative Example 1 was used in conjunction with the non-equilibrium plasma.

[0173] Reaction results: methanol selectivity 44.4%, CH4conversion 30.9%, CO2conversion 33.0%.

[0174] Application Comparative Example 2

[0175] Similar to Application Example 1, except that the catalyst prepared in Application Comparative Example 2 was used in conjunction with the non-equilibrium plasma.

[0176] Reaction results: methanol selectivity 35.7%, CH4conversion 31.0%, CO2conversion 38.8%.

[0177] Application Comparative Example 3

[0178] Similar to Application Example 1, except that the catalyst prepared in Application Comparative Example 3 was used in conjunction with the non-equilibrium plasma.

[0179] Reaction results: methanol selectivity 33.8%, CH4conversion 29.0%, CO2conversion 37.5%

[0180] Application Comparative Example 4

[0181] Similar to Application Example 1, except that the catalyst prepared in Application Comparative Example 4 was used in conjunction with the non-equilibrium plasma.

[0182] Reaction results: methanol selectivity 21.4%, CH4conversion 35.2%, CO2conversion 34.2%

[0183] Of course, the present application can have other various embodiments, and those skilled in the art can make various corresponding changes and modifications to the present application according to the present application without departing from the spirit and essence of the present application, and these corresponding changes and modifications should all belong to the protection scope of the claims of the present application.

Claims

1. Use of a copper-based catalyst for catalyzing the one-step production of methanol from carbon dioxide and methane, characterized in that, The copper-based catalyst is composed of a carrier and an active component, the carrier is a molecular sieve with a silicon-aluminum molar ratio of 1-20, and the active component includes copper; The content of copper in the copper-based catalyst is 0.1%-70% based on the mass of the copper-based catalyst as 100%; The molecular sieve is one or more of X-type molecular sieve and Y-type molecular sieve; A mixed gas of carbon dioxide and methane is introduced into a dielectric barrier discharge reactor containing the copper-based catalyst, and then a step reaction is performed at 100-300 DEG C to obtain methanol; wherein the molar ratio of methane to carbon dioxide is 0.5-5; The preparation method of the copper-based catalyst includes the following steps: The carrier is mixed with a solution of a copper-containing precursor, dried to obtain a precursor of the copper-based catalyst, and finally the precursor of the copper-based catalyst is subjected to aerobic calcination to obtain the copper-based catalyst.

2. Use according to claim 1, characterized in that, The content of copper in the copper-based catalyst is 5%-50% based on the mass of the copper-based catalyst as 100%.

3. The use according to claim 1, wherein The active component further includes one or more of IA, IIA, VIIIB, IIB and lanthanide series metals in the periodic table.

4. The use according to claim 1, wherein The aerobic calcination is non-equilibrium plasma calcination or thermal calcination.

5. The use according to claim 4, wherein the compound is ###0002### The temperature of the non-equilibrium plasma calcination is 200-400 DEG C, and the time is 0.5-3h.

6. The use according to claim 1, wherein The solution of the copper-containing precursor further contains one or more of IA, IIA, VIIIB, IIB and lanthanide series metal precursors in the periodic table.