Nano indium oxide catalyst for selectively regulating and controlling methanol product synthesized by CO2 hydrogenation, preparation method and application of nano indium oxide catalyst

Abstract

The invention provides a nano indium oxide catalyst for selective regulation and control of a methanol product synthesized by CO2 hydrogenation, a preparation method and application thereof, and the preparation method comprises the following steps: S1, completely dissolving an indium precursor in a reaction medium, and then heating, stirring and refluxing for a period of time to obtain a mixed solution; s2, after the mixed solution is cooled, washing and centrifuging for multiple times to obtain a solid product; and S3, drying the solid product in a drying oven to obtain the nano indium oxide catalyst. The nano indium oxide catalyst with a controllable particle size and an average particle size of 5 nm-30 nm is prepared by adopting a method of heating, refluxing and decomposing an indium precursor by adopting an organic solvent, can stably operate under a high-temperature condition, is applied to a fixed bed reaction for synthesizing methanol through CO2 hydrogenation, and has the advantages that the yield is high; the catalyst has high CO2 conversion rate and adjustable methanol selectivity.

Description

Technical Field

[0001] The present invention belongs to the technical field of catalyst preparation, and in particular relates to a nano indium oxide catalyst for selectively regulating the product of methanol synthesis by CO2 hydrogenation, a preparation method and an application thereof. Background Art

[0002] As an important basic chemical raw material, methanol has a wide range of application prospects. It is not only an important raw material for the production of organic chemical products such as formaldehyde, dimethyl ether, and acetic acid, but also a raw material for the production of chemicals or fuels such as olefins, aromatics, and gasoline. In addition, methanol, as a clean energy, can be used as a fuel for internal combustion engines or fuel cells, playing an important role in energy transformation.

[0003] Using clean green hydrogen to convert carbon dioxide (CO2) into methanol is considered one of the most promising ways to achieve renewable energy solutions. This technology can not only realize the resource utilization of CO2 and reduce dependence on fossil energy, but also effectively reduce greenhouse gas emissions, which is of great significance to promoting the sustainable development of human society. CO2 hydrogenation to methanol technology has great strategic significance.

[0004] To achieve efficient CO2 hydrogenation to methanol reaction, it is necessary to develop catalysts with excellent performance. Indium oxide (In2O3) catalysts have unique advantages in CO2 hydrogenation to methanol reaction due to their high activity and good stability. In2O3 catalysts can maintain catalytic activity for a long time, which is particularly important for industrial applications. In2O3 catalysts also have high selectivity and can effectively inhibit the occurrence of side reactions such as methane, thereby increasing the yield of methanol.

[0005] However, in the process of CO2 hydrogenation to methanol, CO produced by the reverse water gas reaction will coexist, which often leads to a decrease in methanol selectivity. Therefore, it is necessary to rationally design the In2O3 catalyst to effectively regulate the selectivity of CO2 hydrogenation to methanol products, thereby improving the production efficiency of the target product methanol. Summary of the invention

[0006] In view of the shortcomings of the prior art described above, the purpose of the present invention is to provide a nano indium oxide catalyst, a preparation method and its application for selective regulation of CO2 hydrogenation to methanol product, so as to solve the problem of reduced methanol selectivity caused by CO produced by the reverse water gas reaction during the CO2 hydrogenation to methanol reaction in the prior art.

[0007] To achieve the above-mentioned object and other related objects, the present invention provides a method for preparing a nano indium oxide catalyst for selectively regulating the product of CO2 hydrogenation to methanol, and the preparation method comprises the following steps:

[0008] S1, completely dissolving the indium precursor in the reaction medium, and then heating, stirring and refluxing for a period of time to obtain a mixed solution;

[0009] S2, after the mixed solution is cooled, it is washed and centrifuged several times to obtain a solid product;

[0010] S3, placing the solid product in an oven for drying to obtain a nano indium oxide catalyst.

[0011] Preferably, the indium precursor in step S1 includes one or a combination of indium acetate and indium acetylacetonate.

[0012] Preferably, the reaction medium in step S1 comprises one or a combination of oleylamine and oleic acid.

[0013] Preferably, in step S1, the mass volume ratio between the indium precursor and the reaction medium is 1 g:(5-100 mL).

[0014] Preferably, the temperature of the heating, stirring and reflux in step S1 is 150°C to 400°C.

[0015] Preferably, the washing and centrifuging steps in step S2 specifically include:

[0016] Adding ethanol to the cooled mixed solution to precipitate, and then centrifuging;

[0017] The solid after centrifugation is dispersed in a non-polar organic solvent for washing, and then ethanol is added to precipitate and centrifuged, and the process is repeated several times.

[0018] Preferably, the non-polar organic solvent includes one or a combination of n-hexane and cyclohexane.

[0019] Preferably, the drying temperature in step S3 is 60-80° C., and the drying time is 6-12 hours.

[0020] Preferably, the average particle size of the nano-indium oxide catalyst obtained in step S3 is 5 nm to 30 nm.

[0021] The present invention also provides a nano indium oxide catalyst, which is prepared by adopting the above-mentioned preparation method of the nano indium oxide catalyst for selectively regulating the synthesis of methanol products by CO2 hydrogenation.

[0022] Preferably, the average particle size of the nano-indium oxide catalyst is 5 nm to 30 nm.

[0023] In addition, the present invention also provides an application of a nano indium oxide catalyst, which is an application of the nano indium oxide catalyst in the CO2 hydrogenation to methanol reaction, wherein the nano indium oxide catalyst is obtained by adopting the above-mentioned preparation method of the nano indium oxide catalyst for selective regulation of the CO2 hydrogenation to methanol product; the CO2 hydrogenation to methanol reaction is specifically, using a mixed gas of H2 and CO2 as raw gas, and carrying out a fixed bed reaction under the action of the nano indium oxide catalyst.

[0024] Preferably, the molar ratio of H2 to CO2 in the raw gas is 1 to 3.

[0025] Preferably, the mass space velocity of the reaction is 2000-20000 mL / min. cat -1 h -1 .

[0026] Preferably, the reaction pressure is 1-5 MPa.

[0027] Preferably, the reaction temperature is 280-320°C.

[0028] As described above, the nano-indium oxide catalyst for selectively controlling the product of CO2 hydrogenation to methanol, the preparation method and the application thereof of the present invention have the following beneficial effects:

[0029] The present invention adopts a method of decomposing an indium precursor by heating and refluxing an organic solvent to prepare a nano indium oxide catalyst with controllable particle size. The preparation process is short and high-temperature calcination is not required, which greatly saves the time cost and economic cost of preparing the catalyst. The particle size of the prepared nano indium oxide catalyst is uniform and adjustable, and its average particle size is 5nm to 30nm. The nano indium oxide catalyst of the present invention can operate stably under high temperature conditions, and is applied to a fixed-bed reaction of CO2 hydrogenation to synthesize methanol, with high CO2 conversion rate and adjustable methanol selectivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Shown is the XRD pattern of the nano indium oxide catalyst prepared in Example 1 of the present invention.

[0031] Figure 2 Shown is a TEM image of the nano-indium oxide catalyst prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0032] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0033] Before further describing the specific embodiments of the present invention, it should be understood that the scope of protection of the present invention is not limited to the specific embodiments described below; it should also be understood that the terms used in the examples of the present invention are intended to describe specific embodiments, rather than to limit the scope of protection of the present invention. The test methods in the following examples without specifying specific conditions are generally carried out under conventional conditions or under conditions recommended by the manufacturers.

[0034] When the embodiments give numerical ranges, it should be understood that, unless otherwise specified in the present invention, both endpoints of each numerical range and any numerical value between the two endpoints can be selected. Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those generally understood by those skilled in the art. In addition to the specific methods, equipment, and materials used in the embodiments, according to the grasp of the prior art by those skilled in the art and the record of the present invention, any methods, equipment, and materials of the prior art similar or equivalent to the methods, equipment, and materials described in the embodiments of the present invention can also be used to realize the present invention.

[0035] In the prior art, the CO produced by the reverse water gas reaction in the CO2 hydrogenation to methanol reaction is simultaneously present, which often results in a decrease in the methanol selectivity. Therefore, it is necessary to regulate the product selectivity of the CO2 hydrogenation to methanol through the reasonable design of a multi-indium oxide catalyst, thereby improving the production efficiency of the target product methanol.

[0036] The present invention provides a method for preparing a nano indium oxide catalyst for selectively regulating the product of methanol synthesis by CO2 hydrogenation, and the preparation method comprises the following steps:

[0037] S1, completely dissolving the indium precursor in the reaction medium, and then heating, stirring and refluxing for a period of time to obtain a mixed solution;

[0038] S2, after the mixed solution is cooled, it is washed and centrifuged several times to obtain a solid product;

[0039] S3. Place the solid product in an oven and dry it to obtain a nano-indium oxide catalyst.

[0040] Specifically, the indium precursor needs to be dissolved in the reaction medium under heating conditions. In a specific embodiment of the present invention, the indium precursor is dissolved in the reaction medium, the temperature is raised to 100°C and heated and stirred for 30 minutes to completely dissolve it; then, under heating reflux conditions, the reaction medium decomposes the indium precursor at high temperature to synthesize a nano-indium oxide catalyst with controllable particle size. After the indium precursor is dissolved in the reaction medium, it decomposes at high temperature, and metal indium nanoparticles are precipitated and oxidized in the air to become nano-indium oxide particles; before the CO2 hydrogenation to methanol reaction, the nano-indium oxide catalyst can directly react without reduction, and can stably operate under high temperature conditions above 280°C, with a high CO2 conversion rate and adjustable methanol selectivity.

[0041] As an example, the indium precursor in step S1 includes one or a combination of indium acetate and indium acetylacetonate.

[0042] As an example, the reaction medium in step S1 includes one or a combination of oleylamine and oleic acid.

[0043] Specifically, the indium precursor is thermally decomposed in the reaction medium, the acetate group or the acetylacetone group falls off, and nano-indium is formed under the protection of oleylamine or oleic acid, and is oxidized by oxygen in the air to form nano-indium oxide particles. The higher the reflux temperature, the easier it is for the nano-particles to aggregate and the larger the particle size.

[0044] As an example, the mass volume ratio between the indium precursor and the reaction medium in step S1 is 1 g:(5-100 mL).

[0045] Specifically, the mass volume ratio between the indium precursor and the reaction medium may include values ​​within any range such as 1g:5mL, 1g:10mL, 1g:30mL, 1g:50mL, 1g:80mL, 1g:100mL, etc.

[0046] As an example, the temperature of heating, stirring and reflux in step S1 is 150°C to 400°C.

[0047] Specifically, the temperature of the heating, stirring and refluxing can include any value within a range of 150° C., 200° C., 250° C., 300° C., 350° C., 400° C., etc. The heating, stirring and refluxing temperature and the reaction medium have a great influence on the particle size of the nanoparticles. The higher the reflux temperature, the easier it is for the nanoparticles to aggregate, and the larger the particle size.

[0048] As an example, the washing and centrifugation steps in step S2 specifically include: adding ethanol to the cooled mixed solution to precipitate, and then centrifuging; dispersing the solid after centrifugation in a non-polar organic solvent for washing, and then adding ethanol to precipitate and centrifuging, and repeating multiple times.

[0049] Specifically, after a precipitation and centrifugation, the solid after centrifugation is dispersed in a non-polar solvent, that is, the nano-indium oxide particles are dispersed into a colloid, and the excess reaction medium is removed. Then, the indium oxide nanoparticles can be precipitated into ethanol to facilitate centrifugation, thereby performing multiple washing and centrifugation steps, and the specific number of times is not limited too much here.

[0050] As an example, the non-polar organic solvent includes one or a combination of n-hexane and cyclohexane.

[0051] As an example, in step S3, the drying temperature is 60-80° C., and the drying time is 6-12 hours.

[0052] Specifically, the drying temperature may include values ​​within any range such as 60°C, 65°C, 70°C, 75°C, 80°C, etc., and the drying time may include values ​​within any range such as 6h, 8h, 10h, 12h, etc.

[0053] As an example, the average particle size of the nano-indium oxide catalyst obtained in step S3 is 5 nm to 30 nm.

[0054] Specifically, the average particle size of the obtained nano-indium oxide catalyst may include values ​​within any range such as 5 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, etc.

[0055] The present invention also provides a nano indium oxide catalyst, which is prepared by adopting the above-mentioned preparation method of the nano indium oxide catalyst for selectively regulating the synthesis of methanol products by CO2 hydrogenation.

[0056] As an example, the average particle size of the nano-indium oxide catalyst is 5 nm to 30 nm.

[0057] Specifically, the average particle size of the nano-indium oxide catalyst may include values ​​within any range such as 5 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, etc.

[0058] In addition, the present invention also provides an application of a nano indium oxide catalyst, an application of the nano indium oxide catalyst in the CO2 hydrogenation to methanol reaction, wherein the nano indium oxide catalyst is obtained by the above-mentioned preparation method of the nano indium oxide catalyst for selective regulation of the CO2 hydrogenation to methanol product; the CO2 hydrogenation to methanol reaction is specifically, using a mixed gas of H2 and CO2 as raw gas, and carrying out a fixed bed reaction under the action of the nano indium oxide catalyst.

[0059] As an example, the molar ratio of H2 to CO2 in the raw gas is 1 to 3.

[0060] Specifically, the molar ratio of H2 to CO2 in the raw gas may include values ​​within any range such as 1, 2, 3, etc.

[0061] As an example, the mass space velocity of the reaction is 2000-20000 mL g cat -1 h -1 .

[0062] Specifically, the mass space velocity may include 2000 mLg cat -1 h -1 、3000mLg cat -1 h -1 , 5000mLg cat -1 h -1 , 10000mLg cat -1 h -1 , 15000mLg cat -1 h -1 , 18000mLg cat -1 h -1 , 20000mLg cat -1 h -1 Any value in the range.

[0063] As an example, the reaction pressure is 1 to 5 MPa.

[0064] Specifically, the reaction pressure may include values ​​within any range such as 1 MPa, 2 MPa, 3 MPa, 4 MPa, 5 MPa, etc., and may be selected based on actual conditions.

[0065] As an example, the reaction temperature is 280-320°C.

[0066] Specifically, the reaction temperature may include values ​​within any range such as 280°C, 290°C, 300°C, 310°C, 320°C, etc.

[0067] In order to better understand the nano indium oxide catalyst, preparation method and application thereof for selective regulation of CO2 hydrogenation to methanol product in the present invention, the nano indium oxide catalyst, preparation method and application thereof for selective regulation of CO2 hydrogenation to methanol product in the present invention are described below with reference to specific embodiments. It should be noted that these embodiments are merely descriptive and do not limit the present invention in any way.

[0068] Example 1

[0069] This embodiment provides a nano indium oxide catalyst for selectively controlling the synthesis of methanol products by CO2 hydrogenation and a preparation method thereof, the preparation method comprising the following steps:

[0070] S1. Weigh 5.825 g of indium acetate and dissolve it in 40 ml of oleylamine. Heat to 100°C and stir for 30 min. After the acetate is completely dissolved, heat the system to 350°C and reflux for 2 h to obtain a mixed solution.

[0071] S2, cooling the mixed solution to room temperature, precipitating a solid with ethanol, then dispersing the solid in n-hexane, washing and centrifuging for multiple times to obtain a solid product;

[0072] S3. The solid product was placed in an oven at 70° C. and dried for 12 h to obtain a nano-indium oxide catalyst.

[0073] This embodiment further provides a nano indium oxide catalyst, which is prepared by the preparation method in this embodiment. The average particle size of the nano indium oxide catalyst in this embodiment is about 20 nm.

[0074] See also Figure 1 The XRD pattern of the nano-indium oxide catalyst prepared in this example shows that the prepared nano-indium oxide is a cubic pure phase indium oxide structure (PDF#06-0416); see Figure 2 TEM image of the nano-indium oxide catalyst prepared in this example. It can be seen from the image that the average particle size of the prepared nano-indium oxide catalyst is uniform spherical particles of about 20 nm.

[0075] The present embodiment also provides an application of a nano-indium oxide catalyst, which is applied to a fixed-bed reaction of CO2 hydrogenation to methanol, specifically comprising: tableting the nano-indium oxide catalyst, granulating the pellets, and sieving the pellets to 40-60 meshes, then weighing 0.5 g of the sieved nano-indium oxide catalyst and mixing it with an equal volume of 40-60 mesh quartz sand, and then loading the mixture into a fixed-bed reactor, wherein the molar ratio of H2 to CO2 in the introduced raw gas is 3, the reaction temperature is 300°C, the reaction pressure is 5 MPa, and the mass space velocity of the reaction is 9000 mL / min. cat -1 h -1 The reaction results are shown in Table 1.

[0076] Example 2

[0077] This embodiment provides a nano-indium oxide catalyst for selectively controlling the synthesis of methanol products by hydrogenation of CO2 and a preparation method thereof. The difference between the preparation method and that in Example 1 is that the temperature of reflux stirring in step S1 is 300°C, and the other steps and methods are the same as those in Example 1 and will not be repeated here.

[0078] This embodiment further provides a nano indium oxide catalyst, which is prepared by the preparation method in this embodiment. The average particle size of the nano indium oxide catalyst in this embodiment is about 17 nm.

[0079] This embodiment also provides an application of a nano-indium oxide catalyst, which is applied to a fixed bed reaction of CO2 hydrogenation to methanol, and the specific method is the same as that in Example 1, which will not be repeated here. The reaction results are shown in Table 1.

[0080] Example 3

[0081] This embodiment provides a nano indium oxide catalyst for selectively controlling the synthesis of methanol products by hydrogenation of CO2 and a preparation method thereof. The difference between the preparation method and that in Example 1 is that the reflux stirring temperature in step S1 is 250°C, and the other steps and methods are the same as those in Example 1 and will not be repeated here.

[0082] This embodiment further provides a nano indium oxide catalyst, which is prepared by the preparation method in this embodiment. The average particle size of the nano indium oxide catalyst in this embodiment is about 12 nm.

[0083] This embodiment also provides an application of a nano-indium oxide catalyst, which is applied to a fixed bed reaction of CO2 hydrogenation to methanol, and the specific method is the same as that in Example 1, which will not be repeated here. The reaction results are shown in Table 1.

[0084] Example 4

[0085] This embodiment provides a nano-indium oxide catalyst for selectively controlling the synthesis of methanol products by hydrogenation of CO2 and a preparation method thereof. The difference between the preparation method and that in Example 1 is that the temperature of reflux stirring in step S1 is 200°C, and the other steps and methods are the same as those in Example 1 and will not be repeated here.

[0086] This embodiment further provides a nano indium oxide catalyst, which is prepared by the preparation method in this embodiment. The average particle size of the nano indium oxide catalyst in this embodiment is about 8 nm.

[0087] This embodiment also provides an application of a nano-indium oxide catalyst, which is applied to a fixed bed reaction of CO2 hydrogenation to methanol, and the specific method is the same as that in Example 1, which will not be repeated here. The reaction results are shown in Table 1.

[0088] Example 5

[0089] This embodiment provides a nano-indium oxide catalyst for selectively controlling the synthesis of methanol products by hydrogenation of CO2 and a preparation method thereof. The difference between the preparation method and that in Example 1 is that the reflux stirring temperature in step S1 is 150°C, and the other steps and methods are the same as those in Example 1 and will not be repeated here.

[0090] This embodiment further provides a nano indium oxide catalyst, which is prepared by the preparation method in this embodiment. The average particle size of the nano indium oxide catalyst in this embodiment is about 5 nm.

[0091] This embodiment also provides an application of a nano-indium oxide catalyst, which is applied to a fixed bed reaction of CO2 hydrogenation to methanol, and the specific method is the same as that in Example 1, which will not be repeated here. The reaction results are shown in Table 1.

[0092] Example 6

[0093] This embodiment provides a nano-indium oxide catalyst for selectively controlling the synthesis of methanol products by hydrogenation of CO2 and a preparation method thereof. The preparation method is the same as that in Example 1 and will not be described in detail here.

[0094] This embodiment further provides a nano indium oxide catalyst, which is prepared by the preparation method in this embodiment. The average particle size of the nano indium oxide catalyst in this embodiment is about 20 nm.

[0095] This embodiment also provides an application of a nano-indium oxide catalyst, which is applied to a fixed bed reaction of CO2 hydrogenation to methanol. The specific method is different from that in Example 1 in that the mass space velocity of the reaction is 20000 mL / min. cat -1 h -1 The other steps are the same as those in Example 1 and will not be described in detail here. The reaction results are shown in Table 1.

[0096] Example 7

[0097] This embodiment provides a nano indium oxide catalyst for selectively controlling the synthesis of methanol products by CO2 hydrogenation and a preparation method thereof, the preparation method comprising the following steps:

[0098] S1. Weigh 4.12 g of indium acetylacetonate and dissolve it in 100 ml of oleylamine. Heat to 100° C. and heat with stirring for 30 min. After the indium acetylacetonate is completely dissolved, heat the system to 400° C. and reflux with stirring for 2 h to obtain a mixed solution.

[0099] S2, cooling the mixed solution to room temperature, precipitating a solid with ethanol, then dispersing the solid in n-hexane, washing and centrifuging for multiple times to obtain a solid product;

[0100] S3. The solid product is placed in an oven at 80° C. and dried for 6 h to obtain a nano-indium oxide catalyst.

[0101] This embodiment further provides a nano indium oxide catalyst, which is prepared by the preparation method in this embodiment. The average particle size of the nano indium oxide catalyst in this embodiment is about 30 nm.

[0102] The present embodiment also provides an application of a nano-indium oxide catalyst, which is applied to a fixed-bed reaction of CO2 hydrogenation to methanol, specifically comprising: tableting the nano-indium oxide catalyst, granulating the pellets, and sieving the pellets to 40-60 meshes, then weighing 0.5 g of the sieved nano-indium oxide catalyst and mixing it with an equal volume of 40-60 mesh quartz sand, and then loading the mixture into a fixed-bed reactor, wherein the molar ratio of H2 to CO2 in the introduced raw gas is 3, the reaction temperature is 320°C, the reaction pressure is 5 MPa, and the mass space velocity of the reaction is 9000 mL / min. cat -1 h -1 The reaction results are shown in Table 1.

[0103] Example 8

[0104] This embodiment provides a nano indium oxide catalyst for selectively controlling the synthesis of methanol products by hydrogenation of CO2 and a preparation method thereof. The preparation method is different from that in Example 7 in that the drying in step S3 is performed at 60°C for 12 hours. The rest is the same as in Example 7 and will not be repeated here.

[0105] This embodiment further provides a nano indium oxide catalyst, which is prepared by the preparation method in this embodiment. The average particle size of the nano indium oxide catalyst in this embodiment is about 30 nm.

[0106] This embodiment also provides an application of a nano indium oxide catalyst, which is applied to a fixed bed reaction of CO2 hydrogenation to methanol. The specific method is different from that in Example 7 in that the reaction temperature is 280°C, and the other conditions are the same as those in Example 7, which will not be described in detail. The reaction results are shown in Table 1.

[0107] Example 9

[0108] The present embodiment provides a nano indium oxide catalyst for selectively controlling the methanol product synthesized by CO2 hydrogenation and a preparation method thereof. The preparation method is different from that in Example 7 in that: in step S1, 4.12 g of indium acetylacetonate is weighed and dissolved in a mixed solution of 100 ml of oleylamine and 10 ml of oleic acid; in step S3, the catalyst is dried at 60°C for 12 hours; the other steps and methods are the same as those in Example 7 and will not be repeated here.

[0109] This embodiment further provides a nano indium oxide catalyst, which is prepared by the preparation method in this embodiment. The average particle size of the nano indium oxide catalyst in this embodiment is about 25 nm.

[0110] This embodiment also provides an application of a nano-indium oxide catalyst, which is applied to a fixed bed reaction of CO2 hydrogenation to methanol. The specific method is different from that in Example 7 in that the reaction temperature is 280°C, the mass space velocity of the reaction is 2000 mL / min, and the reaction temperature is 280°C. cat -1 h -1 The other steps are the same as those in Example 7 and will not be described in detail here. The reaction results are shown in Table 1.

[0111] Example 10

[0112] This embodiment provides a nano-indium oxide catalyst for selectively controlling the synthesis of methanol products by hydrogenation of CO2 and a preparation method thereof. The preparation method is the same as that in Example 1 and will not be described in detail here.

[0113] This embodiment further provides a nano indium oxide catalyst, which is prepared by the preparation method in this embodiment. The average particle size of the nano indium oxide catalyst in this embodiment is about 20 nm.

[0114] This embodiment also provides an application of a nano indium oxide catalyst, which is applied to a fixed bed reaction of CO2 hydrogenation to methanol. The specific method is different from that in Example 1 in that the molar ratio of H2 to CO2 in the introduced raw gas is 1, and the other methods are the same as those in Example 1 and will not be described in detail. The reaction results are shown in Table 1.

[0115] Embodiment 11

[0116] This embodiment provides a nano-indium oxide catalyst for selectively controlling the synthesis of methanol products by hydrogenation of CO2 and a preparation method thereof. The preparation method is the same as that in Example 1 and will not be described in detail here.

[0117] This embodiment further provides a nano indium oxide catalyst, which is prepared by the preparation method in this embodiment. The average particle size of the nano indium oxide catalyst in this embodiment is about 20 nm.

[0118] This embodiment also provides an application of a nano indium oxide catalyst, which is applied to a fixed bed reaction of CO2 hydrogenation to methanol. The specific method is different from that in Example 1 in that the reaction pressure is 1 MPa, and the other conditions are the same as those in Example 1, which will not be described in detail. The reaction results are shown in Table 1.

[0119] Table 1. Reaction results of the nano-indium oxide catalysts prepared in Examples 1 to 9 applied to the fixed-bed reaction of CO2 hydrogenation to methanol.

[0120]

[0121] In summary, the present invention adopts the method of heating and refluxing an organic solvent to decompose an indium precursor to prepare a nano-indium oxide catalyst with controllable particle size. The preparation process is short and does not require high-temperature calcination, which greatly saves the time cost and economic cost of preparing the catalyst; the particle size of the prepared nano-indium oxide catalyst is uniform and adjustable, and its average particle size is 5nm to 30nm; and the nano-indium oxide catalyst in the present invention can operate stably under high temperature conditions, and is applied to the fixed bed reaction of CO2 hydrogenation to synthesize methanol, with high CO2 conversion rate and adjustable methanol selectivity. Therefore, the present invention effectively overcomes the various shortcomings of the prior art and has high industrial utilization value.

[0122] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A method for preparing a nano-indium oxide catalyst for selectively regulating the product of CO2 hydrogenation to synthesize methanol, characterized in that: The preparation method comprises the following steps: S1, completely dissolving the indium precursor in the reaction medium, and then heating, stirring and refluxing for a period of time to obtain a mixed solution; S2, after the mixed solution is cooled, it is washed and centrifuged several times to obtain a solid product; S3, placing the solid product in an oven for drying to obtain a nano indium oxide catalyst.

2. The method for preparing a nano indium oxide catalyst for selectively regulating the product of CO2 hydrogenation to methanol according to claim 1, characterized in that: Step S1 includes one or a combination of the following conditions: The indium precursor includes one or a combination of indium acetate and indium acetylacetonate; The reaction medium includes one or a combination of oleylamine and oleic acid; The mass volume ratio between the indium precursor and the reaction medium is 1 g:(5-100 mL).

3. The method for preparing a nano indium oxide catalyst for selectively regulating the product of CO2 hydrogenation to methanol according to claim 1, characterized in that: The temperature of the heating, stirring and reflux in step S1 is 150°C to 400°C.

4. The method for preparing a nano indium oxide catalyst for selectively regulating the product of CO2 hydrogenation to methanol according to claim 1, characterized in that: The steps of washing and centrifuging in step S2 specifically include: Adding ethanol to the cooled mixed solution to precipitate, and then centrifuging; The solid after centrifugation is dispersed in a non-polar organic solvent for washing, and then ethanol is added to precipitate and centrifuged, and the process is repeated several times.

5. The method for preparing a nano indium oxide catalyst for selectively regulating the product of CO2 hydrogenation to methanol according to claim 4, characterized in that: The non-polar organic solvent includes one or a combination of n-hexane and cyclohexane.

6. The method for preparing a nano indium oxide catalyst for selectively regulating the product of CO2 hydrogenation to methanol according to claim 1, characterized in that: Step S3 includes one or a combination of the following conditions: The drying temperature is 60-80°C and the drying time is 6-12h; The average particle size of the obtained nano indium oxide catalyst is 5nm to 30nm.

7. A nano indium oxide catalyst, characterized in that: The nano indium oxide catalyst is prepared by the preparation method of the nano indium oxide catalyst for selectively regulating the product of methanol synthesis by CO2 hydrogenation according to any one of claims 1 to 6.

8. The nano indium oxide catalyst according to claim 7, characterized in that: The average particle size of the nano indium oxide catalyst is 5nm to 30nm.

9. An application of a nano indium oxide catalyst, characterized in that: The application of the nano indium oxide catalyst in the CO2 hydrogenation to methanol reaction, wherein the nano indium oxide catalyst is obtained by the preparation method of the nano indium oxide catalyst for selective regulation of the CO2 hydrogenation to methanol product as described in any one of claims 1 to 6; the CO2 hydrogenation to methanol reaction is specifically, using a mixed gas of H2 and CO2 as raw gas, and carrying out a fixed bed reaction under the action of the nano indium oxide catalyst.

10. The use of the nano indium oxide catalyst according to claim 9, characterized in that: Includes one or more of the following conditions: The molar ratio of H2 to CO2 in the raw gas is 1 to 3; The mass space velocity of the reaction is 2000-20000 mL / min. cat -1 h -1 ; The reaction pressure is 1-5 MPa; The reaction temperature is 280-320°C.

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