Supported catalyst and preparation method thereof

Abstract

The invention relates to the technical field of catalysis, in particular to a supported catalyst and a preparation method thereof, and a method for preparing carbon monoxide through hydrogenation of carbon dioxide. The supported catalyst comprises a carrier and an active component, and the active component is selected from at least one of ruthenium, platinum and palladium; the carrier is amino-modified silicon dioxide, and the content of a nitrogen element in the carrier is 5-15 wt%. According to the supported catalyst, the amino modifier is adopted to carry out functional modification on the silicon dioxide, and the modified silicon dioxide is used as a carrier, so that the obtained catalyst has high dispersion, relatively high metal utilization rate, high catalytic reaction activity and high selectivity on a target product.

Description

Technical Field

[0001] The present invention relates to the field of catalytic technology, and in particular to a supported catalyst and a preparation method thereof, and a method for preparing carbon monoxide by hydrogenating carbon dioxide. Background Art

[0002] CO2 is an economical, safe and renewable carbon source. The preparation of syngas from CO2 and its conversion into hydrocarbons or high-value-added chemicals through the CO hydrogenation process can not only mitigate the impact of climate change caused by CO2 emissions, but also make up for the shortage of fossil fuels. Therefore, the effective use of CO2 is crucial to the sustainable development of our society. The CO produced by reverse water gas shift (RWGS) has high application value and can be used for methanol synthesis and CO hydrogenation to produce chemicals and fuels. CO2 has high stability, resulting in low reaction activity and product selectivity in CO2 hydrogenation reactions. Ru has been widely studied due to its ability to activate CO2 and H2 simultaneously and is the most economical precious metal. Supported Ru-based catalysts have shown superior activity and selectivity in this reaction. However, achieving high CO selectivity with supported Ru catalysts remains a challenging task. When oxides are used as carriers, the interaction between metal and carrier is strong, forming metal oxides such as silicates or aluminates, which makes it difficult to reduce some metals, thereby reducing the activity and life of the catalyst.

[0003] The literature (Energy & Environmental Science, 2013, 6 (11): 3112-3135.) reports that the metal particle size has an important influence on the catalytic performance of the catalyst. When the Ru particle size in the Ru / Al2O3 catalyst is monolayer distributed, the main product of CO2 hydrogenation is CO. However, the interaction between Al2O3 and Ru is too strong, resulting in low metal utilization and low reaction activity. The literature (Energy & Environmental Science, 2009, 2: 315-321.) reports that when the metal particle size is greater than 2.5nm, the selectivity of CO2 hydrogenation product CH4 is almost 100%. The literature (ACS Catal 2013, 3: 2449-2455) reports that the initial CO selectivity of 0.1Ru / Al2O3 catalyst is higher than 90%, but after 4h of reaction, the selectivity drops to less than 50%. The literature (Applied Catalysis B: Environmental, 2017, 219: 580-591) first synthesized 1-3 nm Ru nanoparticles, and then encapsulated them in SiO2 to obtain Ru@mSiO2 catalyst, which has a CO selectivity of about 80% in the CO2 hydrogenation reaction. This method is relatively complicated, and the Ru nanoparticles are large in size, resulting in relatively low CO selectivity. Summary of the invention

[0004] In order to overcome the problems existing in the prior art, the inventors of the present invention have conducted extensive and in-depth research and provided a supported catalyst and a preparation method thereof, and a method for preparing carbon monoxide by hydrogenating carbon dioxide. For example, one of the purposes of the present invention is to provide a supported catalyst, wherein silicon dioxide is functionally modified by an amino modifier, and the modified silicon dioxide is used as a carrier, and the obtained catalyst has high dispersion, high metal utilization, high catalytic reaction activity and high selectivity for the target product. For another example, another purpose of the present invention is to provide a preparation method corresponding to the above-mentioned supported catalyst.

[0005] In order to achieve the above object, the first aspect of the present invention provides a supported catalyst, comprising a carrier and an active component, wherein the active component is selected from at least one of ruthenium, platinum and palladium.

[0006] In some embodiments of the present invention, the carrier is amino-modified modified silica, and the nitrogen content in the carrier is 5-15wt%. Amino modification increases the number of amino groups on the surface of the carrier, which is manifested as an increase in the nitrogen content in the carrier. In the present invention, the nitrogen content in the carrier silica that is not amino-modified is 0.

[0007] In the present invention, the specific surface area of ​​the amino-modified modified silica is not less than 200 m 2 / g, preferably, the specific surface area is 200 to 400m 2 / g.

[0008] In some embodiments of the present invention, the specific surface area of ​​the supported catalyst is 100 to 700 m 2 / g.

[0009] In some embodiments of the present invention, the metal particle size of the active component is 0.5 to 5 nm.

[0010] In some embodiments of the present invention, the dispersion degree of the active component is 50-96%.

[0011] In the present invention, the method for determining the dispersion degree can be CO chemical adsorption method, H2 chemical adsorption method, hydrogen oxygen titration method, TEM, etc., but is not limited thereto.

[0012] In the present invention, the silicon dioxide is functionally modified with an amino modifier, and the chemical environment of the silicon dioxide surface can be regulated by adjusting the amount of the amino modifier added. Within an appropriate range, the higher the amount of the amino modifier added, the more amino groups on the carrier surface and the better the metal dispersion effect. However, if too much amino modifier is added, cross-linking will occur, resulting in a reduced effect.

[0013] In some embodiments of the present invention, in the supported catalyst, the mass ratio of the active component to the carrier is (0.1-10):100, preferably (0.1-5):100, and more preferably (0.5-5):100.

[0014] In some embodiments of the present invention, the preparation of the carrier (i.e., amino-modified modified silica) comprises the following steps:

[0015] S101, subjecting a first reaction solution containing silicon dioxide, an amino modifier and a solvent I to a first reaction to obtain a reaction solution I;

[0016] S102, performing solid-liquid separation on the reaction solution I, and optionally washing and drying the separated solid phase in sequence to obtain the amino-modified modified silica.

[0017] According to the present invention, the modification experiment of silica can be carried out in a round bottom flask.

[0018] In some embodiments of the present invention, in step S101, the silicon dioxide is selected from one or more of fumed silicon dioxide, alkaline silica sol, acidic silica sol, and synthetic silicon dioxide. The preparation method of the synthetic silicon dioxide used in the present invention is a conventional ethyl orthosilicate hydrolysis method, which can be prepared by those skilled in the art according to the prior art, and the present invention will not repeat it in detail.

[0019] In the present invention, the specific surface area of ​​the silicon dioxide before the modification experiment is 200-450m 2 / g.

[0020] In some embodiments of the present invention, in step S101, the amino modifier is selected from at least one of silane coupling agent KH550, 6-aminocaproic acid and 4-aminobutyric acid.

[0021] In some embodiments of the present invention, in step S101, the solvent I is water and / or C1-C4 alcohol; preferably, the mass ratio of water to C1-C4 alcohol in the solvent I is (0-2):1, preferably (0-1):1.

[0022] In the present invention, the C1-C4 alcohol is selected from one or more of methanol, ethanol, ethylene glycol, propanol, isopropanol and butanol.

[0023] In some embodiments of the present invention, in step S101, the mass ratio of the silicon dioxide to the solvent I is 1:(5-500), preferably 1:(10-300).

[0024] In some embodiments of the present invention, in step S101, the mass ratio of the silicon dioxide to the amino modifier is 1:(0.1-10), preferably 1:(0.2-5).

[0025] In some embodiments of the present invention, in step S101, the reaction conditions of the first reaction include: temperature of 40°C to 120°C, preferably 40°C to 100°C; time of 2 to 72 hours, preferably 6 to 48 hours.

[0026] In the present invention, the first reaction can be performed by high temperature reflux.

[0027] The present invention does not have a strict limitation on the solid-liquid separation process in step S102, and those skilled in the art may determine it according to actual conditions.

[0028] After the solid-liquid separation process is completed, the obtained solid phase can be washed and dried in sequence to finally obtain the amino-modified modified silica.

[0029] In some embodiments of the present invention, in step S102, the drying treatment conditions include: a temperature of 40°C to 180°C, preferably 60°C to 180°C; and a time of 8 to 48 hours, preferably 8 to 36 hours.

[0030] In the present invention, the reagents used above can all be purchased commercially.

[0031] In the present invention, an amino modifier is used to functionalize silica, and the modified silica is used as a carrier. The high specific surface area of ​​the modified silica as a carrier and the anchoring effect of the amino group can greatly improve the metal dispersion and reduce the metal particle size, so that the catalyst anchored on the modified silica carrier of the present invention has high dispersion, high metal utilization, high catalytic reaction activity and selectivity for the target product.

[0032] The second aspect of the present invention provides a method for preparing the supported catalyst as described in the first aspect, comprising the steps of:

[0033] S1, providing a catalyst precursor containing an active component source and the carrier;

[0034] S2. calcining the catalyst precursor to obtain the supported catalyst.

[0035] In some embodiments of the present invention, the active component source is selected from one or more of ruthenium nitrosyl nitrate, ruthenium chloride, ruthenium acetylacetonate, ruthenium nitrate, ammonium hexachlororuthenate, platinum nitrate, chloroplatinic acid solution, platinum tetrachloride, platinum acetylacetonate, ammonium chloroplatinate, tetraammonium dichloroplatinum, palladium chloride, palladium nitrate, ammonium chloropalladate, palladium acetate and di(acetylacetonate)palladium.

[0036] In the present invention, di(acetylacetonate)palladium is di(acetylacetonate)palladium(II), and its molecular formula is C 10 H16 O4Pd, CAS No. 14024-61-4. The above active component sources of the present invention can be obtained through commercial channels.

[0037] In the present invention, the active component source can be anchored on the surface of the carrier (amino-modified modified silica) by methods commonly used in the field, such as impregnation method and hydrothermal method.

[0038] In some embodiments of the present invention, performing step S1 by a hydrothermal method comprises the steps of:

[0039] S11, providing a precursor solution containing an active component source;

[0040] S12, after mixing the precursor solution with the carrier, the solid phase is washed and dried in sequence after separation to obtain the catalyst precursor.

[0041] In some embodiments of the present invention, in step S11, the solvent II used as the precursor solution is selected from one or more of water, methanol, ethanol, ethylene glycol, propanol, isopropanol and butanol. The present invention has no strict limitation on the content of the solvent II in the precursor solution, and those skilled in the art can determine it according to actual conditions.

[0042] In some embodiments of the present invention, in step S12, the mixing can be performed by reflux. The mixing temperature is 40°C to 120°C, preferably 60°C to 100°C, and the mixing time is 2 to 24 hours, preferably 4 to 12 hours.

[0043] In some embodiments of the present invention, in step S12, separation can be performed by filtering after centrifugation. The washing treatment can be performed by reagents such as anhydrous ethanol, and the present invention is not strictly limited. The drying treatment is preferably performed in air, an inert gas atmosphere or a vacuum. The conditions for the drying treatment include: a temperature of 40°C-180°C, preferably 80°C-160°C; a time of 1-48h, preferably 8-24h.

[0044] In some embodiments of the present invention, those skilled in the art may prepare the catalyst by an impregnation method according to actual conditions.

[0045] In some embodiments of the present invention, in step S2, the conditions of the calcination treatment include: a temperature of 200°C to 600°C, preferably 200°C to 400°C; and a time of 1 to 12 hours, preferably 2 to 8 hours.

[0046] In the present invention, the calcination treatment is preferably carried out in an inert gas atmosphere (such as one or more of nitrogen, argon, neon, and helium).

[0047] In the present invention, the preparation method of the carrier can be as described above, and will not be described in detail here.

[0048] The third aspect of the present invention provides a method for preparing carbon monoxide by hydrogenating carbon dioxide, which comprises the steps of: subjecting carbon dioxide to a hydrogenation reaction in the presence of hydrogen, carbon dioxide and a catalyst; wherein the catalyst is the supported catalyst described in the first aspect above or the supported catalyst obtained by the preparation method described in the second aspect.

[0049] In some embodiments of the present invention, when the hydrogenation reaction is carried out, the molar ratio of hydrogen to carbon dioxide is 3 to 4:1.

[0050] In some embodiments of the present invention, the conditions of the hydrogenation reaction include: reaction temperature of 160°C to 360°C; preferably 180°C to 320°C; pressure of 0.1 to 3MPa, preferably 0.1 to 2.5MPa; space velocity of hydrogen and carbon dioxide of 2000 to 30000NL·kg -1 ·h -1 .

[0051] In some embodiments of the present invention, before the hydrogenation reaction, the catalyst is activated; the conditions of the activation treatment include:

[0052] The activation atmosphere is hydrogen, carbon monoxide or synthesis gas; wherein the molar ratio of hydrogen to carbon monoxide in the synthesis gas is (1-1000):1, preferably (2-500):1;

[0053] The activation pressure is 0.1 to 3 MPa, preferably 0.1 to 2 MPa;

[0054] The activation temperature is 100°C to 500°C, preferably 150°C to 400°C.

[0055] Before the hydrogenation reaction, the catalyst is activated and reduced to generate metal active sites.

[0056] According to the present invention, the reaction progress of hydrogenating carbon dioxide to produce carbon monoxide can be analyzed online by gas chromatography to monitor the reaction.

[0057] In some embodiments of the present invention, the method for preparing carbon monoxide by hydrogenating carbon dioxide includes the steps of: granulating the catalyst prepared by the first aspect to obtain catalyst particles of 20 to 40 mesh, and then placing 0.1 to 1 g of the catalyst in a constant temperature zone of a fixed bed reactor, with quartz sand filled on both sides; activating the catalyst with H2 at 150°C to 400°C and 0.1 to 2 MPa for 2 to 12 hours, after which the temperature is reduced to 100°C, the gas is switched to a H2 / CO2 mixed gas, H2 / CO2=3, the reaction pressure is 0.1 to 3 MPa, and then the reaction temperature is increased to 160 to 360°C at 10°C / h, the reaction is carried out, and the product composition is analyzed online by gas chromatography.

[0058] Compared with the prior art, the present invention has at least one of the following beneficial effects:

[0059] 1) The supported catalyst provided by the present invention is obtained by modifying conventional silicon dioxide and using it as a carrier to load active components. The obtained catalyst has good catalytic performance and can effectively improve metal utilization;

[0060] 2) The method for preparing the supported catalyst provided by the present invention can use a relatively simple preparation process to obtain a supported catalyst with better catalytic performance;

[0061] 3) The method for preparing carbon monoxide by hydrogenating carbon dioxide provided by the present invention uses the above-mentioned supported catalyst, and the carbon dioxide conversion rate is high, the selectivity of carbon monoxide can reach more than 95%, and the catalyst has a longer stable operation time. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 The XRD spectrum of catalyst Exam-1 in Example 1 is shown;

[0063] Figure 2 shows a TEM image of catalyst Exam-1 in Example 1;

[0064] Figure 3 The graph shows the CO2 hydrogenation reaction conversion rate change curve in Example 1. DETAILED DESCRIPTION

[0065] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0066] In the present invention, unless otherwise specified, the terms "active component", "active phase metal" and "metal active phase" are used interchangeably and all refer to the metal component used as the active phase of the hydrogenation catalyst.

[0067] In the present invention, unless otherwise specified, the term "grain size" or "particle size" refers to the size of the crystal phase particles of the catalyst, which can be measured by scanning electron microscopy or transmission electron microscopy, but is not limited thereto.

[0068] In the present invention, unless otherwise specified, the term "normal pressure" refers to one standard atmospheric pressure.

[0069] The present invention is described in detail below by way of examples, but the protection scope of the present invention is not limited to the following description.

[0070] In the present invention, the specific surface area is measured by the BET method (Brubauer-Emmet-Teller). For example, the measurement method is described in standard NFX11-62.

[0071] In the present invention, X-ray photoelectron spectroscopy (XPS) is used to measure the nitrogen content in the carrier.

[0072] In the present invention, the method for determining the dispersion degree may be CO chemical adsorption method, H2 chemical adsorption method, hydrogen oxygen titration method, TEM, etc., but is not limited thereto. In the following examples, the method for determining the dispersion degree is the TEM method.

[0073] In the present invention, the calculation method of CO selectivity is:

[0074]

[0075] In the formula, n(CO out ) represents the amount of CO in the exhaust gas; Indicates the amount of CO2 in the raw gas; n(CO 2out ) represents the amount of CO2 in the exhaust gas.

[0076] In the present invention, the calculation method of CO2 conversion rate is:

[0077]

[0078] In the formula, Indicates the amount of CO2 in the raw gas; Indicates the amount of CO2 in the exhaust gas.

[0079] If the specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or the conditions recommended by the manufacturer. The raw materials, reagents or instruments used without specifying the manufacturer are all conventional products that can be obtained through commercial channels or prepared according to the preparation methods disclosed in the prior art.

[0080] In the following examples, fumed silica was purchased from Aladdin; synthetic silica was prepared by hydrolysis of ethyl orthosilicate; the organosilane alkylating agent 3-aminopropyltriethoxysilane was from Sinopharm; and aminocaproic acid was from Sinopharm.

[0081] Example 1

[0082] 1. The preparation method of the supported catalyst of this embodiment comprises the steps of:

[0083] (1) Weigh 5 g of fumed silica (400 m 2 / g) was placed in a round-bottom flask, mixed with 140mL of anhydrous ethanol, and 5.18g of organosilane alkylating agent 3-aminopropyltriethoxysilane (KH550) was slowly added under stirring, and refluxed at 100°C for 48h;

[0084] (2) After cooling to room temperature, the solution was centrifuged to obtain a solid, which was then washed three times with anhydrous ethanol and placed in an oven at 100° C. for 12 h to obtain an amino-modified modified silica carrier (specific surface area of ​​385 m 2 / g, nitrogen content is 15%);

[0085] (3) Weigh 0.320 g of ruthenium nitrosyl nitrate and dissolve it in 30 mL of deionized water to form a metal precursor solution;

[0086] (4) Weigh 5 g of the amino-modified modified silica prepared above into a beaker, drop the metal precursor solution onto the support, stir evenly, and let stand for 24 h;

[0087] (5) The beaker in the above step (4) was placed in an oven at 80°C and the sample was dried for 24 hours to obtain a catalyst precursor.

[0088] (6) The catalyst precursor was placed in a tubular furnace, argon gas was introduced at a flow rate of 100 mL / min, the temperature was raised to 250 °C at a heating rate of 2 °C / min, the mixture was kept for 4 h for calcination, and naturally cooled to room temperature to obtain a catalyst with a metal Ru loading of 2 wt% (2% Ru / mSiO2), which was labeled as Exam-1.

[0089] Figure 1 is the XRD spectrum of catalyst Exam-1; Figure 2 This is the TEM image of catalyst Exam-1. Figure 1 and Figure 2It can be seen that the metal particle size of the obtained catalyst Exam-1 is small and has a high dispersion.

[0090] According to TEM images and measurements, the specific surface area of ​​catalyst Exam-1 is 372 m 2 / g; the metal particle size is 1.8nm; the dispersion of the active component is 73.3%.

[0091] 2. Experiment on the production of carbon monoxide by hydrogenation of carbon dioxide

[0092] Take 0.5g of the catalyst Exam-1 prepared above and place it in the constant temperature section of the fixed bed reactor. Reduce the catalyst Exam-1 in H2 at 250℃ and 0.1MPa for 6h. After cooling to 100℃, switch to a mixture of hydrogen and CO2 (H2 / CO2 molar ratio is 3) with a pressure of 0.1MPa, slowly raise the temperature to 240℃, and heat at 10000NL·kg -1 ·h -1 The CO2 hydrogenation reaction was carried out under the following conditions. The CO2 conversion rate (i.e., the conversion rate of the reactants) and the CO selectivity of the reaction are shown in Table 1.

[0093] Example 2

[0094] 1. The preparation method of the supported catalyst of this embodiment comprises the steps of:

[0095] (1) Weigh 5 g of synthetic silicon dioxide (420 m 2 / g) was placed in a round-bottom flask, mixed with 180 mL of propanol, and 6.52 g of aminocaproic acid was slowly added under stirring, and refluxed at 100 °C for 36 h;

[0096] (2) After cooling to room temperature, the solution was centrifuged to obtain a solid, which was then washed three times with anhydrous ethanol and placed in an oven to dry at 80°C for 24 h to obtain an amino-modified modified silica carrier (specific surface area of ​​396 m 2 / g, nitrogen content is 15%);

[0097] (3) Take 0.0714 g of RuCl3·3H2O and add 180 mL of anhydrous ethanol to dissolve. After the RuCl3·3H2O is dissolved, add 5 g of the prepared modified silica, stir, and reflux at 80°C for 24 h;

[0098] (4) After the reaction is completed, the solution is cooled to room temperature, centrifuged, washed with anhydrous ethanol three times, and dried at 80° C. for 12 h to obtain a catalyst precursor;

[0099] (5) The catalyst precursor was placed in a tubular furnace, argon gas was introduced at a flow rate of 100 mL / min, the temperature was raised to 200 °C at a heating rate of 2 °C / min, the mixture was kept for 4 h for calcination, and naturally cooled to room temperature to obtain a catalyst with a metal Ru loading of 0.5 wt% (0.5% Ru / mSiO2), which was labeled as Exam-2.

[0100] According to TEM images and measurements, the specific surface area of ​​catalyst Exam-2 is 380 m 2 / g; the metal particle size is 1.1nm; the dispersion of the active component is 93.2%.

[0101] 2. Experiment on the production of carbon monoxide by hydrogenation of carbon dioxide

[0102] Take 0.5g of the catalyst Exam-2 prepared above and place it in the constant temperature section of the fixed bed reactor. Reduce the catalyst Exam-2 in H2 at 250℃ and 0.1MPa for 6h. After cooling to 100℃, switch to a mixture of hydrogen and CO2 (H2 / CO2 molar ratio is 3) with a pressure of 0.1MPa, slowly raise the temperature to 300℃, and at 5000NL·kg -1 ·h -1 The CO2 hydrogenation reaction was carried out under the following conditions. The CO2 conversion rate (i.e., the conversion rate of the reactants) and the CO selectivity of the reaction are shown in Table 1.

[0103] Example 3

[0104] (1) Weigh 5 g of synthetic silica (300 m 2 / g) in a round-bottom flask, mixed with 120mL of propanol, slowly added with 2.41g of tetraaminobutyric acid under stirring, and refluxed at 130°C for 24h;

[0105] (2) After cooling to room temperature, the solution was centrifuged to obtain a solid, which was then washed three times with anhydrous ethanol and placed in an oven to dry at 80°C for 24 h to obtain an amino-modified modified silica carrier (specific surface area of ​​272 m 2 / g, nitrogen content is 14%);

[0106] (3) Take 0.083 g of PdCl2 and add 160 mL of anhydrous ethanol to dissolve it. After PdCl2 is dissolved, add 5 g of the prepared modified silica, stir, and reflux at 80°C for 24 h;

[0107] (4) After the reaction is completed, the solution is cooled to room temperature, centrifuged, washed with anhydrous ethanol three times, and dried at 80° C. for 12 h to obtain a catalyst precursor;

[0108] (5) The catalyst precursor was placed in a tubular furnace, nitrogen was introduced at a flow rate of 100 mL / min, the temperature was raised to 200 °C at a heating rate of 2 °C / min, the mixture was kept for 4 h for calcination, and naturally cooled to room temperature to obtain a catalyst with a metal Pd loading of 1 wt% (1% Pd / mSiO2), which was labeled as Exam-3.

[0109] According to TEM images and measurements, the specific surface area of ​​catalyst Exam-3 is 254m 2 / g; the metal particle size is 1.5nm; the dispersion of the active component is 88%.

[0110] 2. Experiment on the production of carbon monoxide by hydrogenation of carbon dioxide

[0111] Take 0.5g of the catalyst Exam-3 prepared above and place it in the constant temperature section of the fixed bed reactor. Reduce the catalyst Exam-3 in H2 at 200℃ and 0.1MPa for 6h. After cooling to 100℃, switch to a mixture of hydrogen and CO2 (H2 / CO2 molar ratio is 3) with a pressure of 0.1MPa, slowly raise the temperature to 260℃, and at 5000NL·kg -1 ·h -1 The CO2 hydrogenation reaction was carried out under the following conditions. The CO2 conversion rate (i.e., the conversion rate of the reactants) and the CO selectivity of the reaction are shown in Table 1.

[0112] Example 4

[0113] 1. The preparation method of the supported catalyst of this embodiment comprises the steps of:

[0114] The method is basically the same as Example 1, except that 0.17 g of platinum tetrachloride is used to replace 0.32 g of ruthenium nitrosyl nitrate. Under the same other conditions, catalyst Exam-4 is obtained. The specific surface area of ​​catalyst Exam-4 is 370 m 2 / g; the metal particle size is 1.7nm; the dispersion of the active component is 77.6%.

[0115] 2. Experiment on the production of carbon monoxide by hydrogenation of carbon dioxide

[0116] It is basically the same as Example 1, except that the reaction temperature is 220°C. The CO2 conversion rate (i.e., the conversion rate of the reactants) and the CO selectivity of the reaction are shown in Table 1.

[0117] Example 5

[0118] 1. The preparation method of the supported catalyst of this embodiment comprises the steps of:

[0119] It is basically the same as Example 1, except that "weigh 0.02 g of ruthenium acetylacetonate and dissolve it in 30 mL of anhydrous ethanol" is used instead of "weigh 0.320 g of ruthenium nitrosyl nitrate and dissolve it in 30 mL of deionized water". Under the same other conditions, the catalyst (0.1% Ru / mSiO2) Exam-5 is prepared.

[0120] According to TEM images and measurements, the specific surface area of ​​catalyst Exam-5 is 375m 2 / g; the metal particle size is 0.8nm; the dispersion of the active component is 95.1%.

[0121] 2. Experiment on the production of carbon monoxide by hydrogenation of carbon dioxide

[0122] The reaction was basically the same as in Example 1, except that the reaction temperature was 300°C, the pressure was 1 MPa, and the air velocity was 2000 NL·kg -1 ·h -1 The CO2 conversion rate (i.e., the conversion rate of the reactants) and the CO selectivity of the reaction are shown in Table 1.

[0123] Example 6

[0124] 1. The preparation method of the supported catalyst of this embodiment comprises the steps of:

[0125] It is basically the same as Example 1, except that 0.80g of ruthenium nitrosyl nitrate is used to replace 0.32g of ruthenium nitrosyl nitrate. Under the same other conditions, a catalyst (5% Ru / mSiO2) Exam-6 is prepared.

[0126] According to TEM images and measurements, the specific surface area of ​​catalyst Exam-6 is 361m 2 / g; the metal particle size is 2.4nm; the dispersion degree of the active component is 55%.

[0127] 2. Experiment on the production of carbon monoxide by hydrogenation of carbon dioxide

[0128] The reaction was basically the same as in Example 1, except that the reaction temperature was 200°C and the air velocity was 30000 NL·kg -1 ·h -1 The CO2 conversion rate (i.e., the conversion rate of the reactants) and the CO selectivity of the reaction are shown in Table 1.

[0129] Comparative Example 1

[0130] 1. The preparation method of the supported catalyst of this comparative example comprises the following steps:

[0131] (1) Weigh 0.080 g of ruthenium nitrosyl nitrate and dissolve it in 33 mL of deionized water to form a metal precursor solution;

[0132] (2) Weigh 5 g of fumed silica (400 m 2 / g) in a beaker, drop the metal precursor solution onto the support, stir evenly, and let stand for 24h;

[0133] (3) placing the beaker in the above step (2) in an oven and drying at 80° C. for 24 h to obtain a catalyst precursor;

[0134] (4) The catalyst precursor was placed in a tubular furnace, argon gas was introduced at a flow rate of 100 mL / min, the temperature was raised to 300 °C at a heating rate of 2 °C / min, the mixture was kept for 4 h for calcination, and the mixture was naturally cooled to room temperature to obtain a catalyst 0.5% Ru / SiO2, which was labeled as CE-1.

[0135] According to TEM images and measurements, the specific surface area of ​​catalyst CE-1 is 380 m 2 / g; the metal particle size is 3.5nm; the dispersion of the active component is 37.7%.

[0136] 2. Experiment on the production of carbon monoxide by hydrogenation of carbon dioxide

[0137] Take 0.5g of the catalyst CE-1 prepared above and place it in the constant temperature section of the fixed bed reactor. Reduce the catalyst CE-1 in H2 at 250℃ and 0.1MPa for 6h. After cooling to 100℃, switch to a mixture of hydrogen and CO2 (H2 / CO2 molar ratio is 3) at a pressure of 0.1MPa, slowly raise the temperature to 300℃, and heat at 5000NL·kg -1 ·h -1 The CO2 hydrogenation reaction was carried out under the following conditions. The CO2 conversion rate (i.e., the conversion rate of the reactants) and the CO selectivity of the reaction are shown in Table 1.

[0138] Comparative Example 2

[0139] 1. The preparation method of the supported catalyst of this comparative example comprises the following steps:

[0140] The same as Example 1, except that unmodified fumed silica (400 m 2 / g) to replace the modified silica carrier in Example 1. Under the same other conditions, the finished catalyst product CE-2 was obtained.

[0141] According to TEM images and measurements, the specific surface area of ​​catalyst CE-2 is 362 m 2 / g; the metal particle size is 4.8nm; the dispersion of the active component is 27.5%.

[0142] 2. Experiment on the production of carbon monoxide by hydrogenation of carbon dioxide

[0143] Similar to Example 1, the CO2 conversion rate (i.e., the conversion rate of the reactants) and the CO selectivity of the reaction are shown in Table 1.

[0144] In the above examples and comparative examples, the CO2 conversion rate (i.e., the conversion rate of the reactants) and the CO selectivity of the carbon dioxide hydrogenation reaction to produce carbon monoxide are shown in Table 1 below:

[0145]

[0146] It can be seen from the results in the above table that, by comparing Example 2 with Comparative Example 1, under the same reaction conditions, when the catalyst of Example 2 is used for hydrogenation of carbon dioxide to produce carbon monoxide, the CO2 conversion rate is increased and the CO selectivity is greatly improved.

[0147] Figure 3 The CO2 conversion rate curve of the catalyst Exam-1 of Example 1 in the CO2 hydrogenation reaction is shown. The catalyst Exam-1 runs stably for 120 hours in the CO2 hydrogenation reaction, and the CO2 conversion rate is relatively stable.

[0148] Comparing Example 1 with Comparative Example 2, the CO2 conversion rate and CO selectivity are significantly improved by using the modified silica carrier.

[0149] Compared with Examples 1 to 6, the catalyst Exam-5 obtained in Example 5 has the highest CO selectivity when used for hydrogenation of carbon dioxide to produce carbon monoxide, indicating that the smaller the metal particle size, the higher the CO selectivity.

[0150] Any numerical value mentioned in the present invention, if there is only an interval of two units between any minimum value and any maximum value, includes all values ​​from the minimum value to the maximum value each time increasing by one unit. For example, if the amount of a component, or the value of a process variable such as temperature, pressure, time, etc. is declared to be 50-90, in this specification it means that 51-89, 52-88... and 69-71 and 70-71 are specifically listed. For non-integer values, 0.1, 0.01, 0.001 or 0.0001 can be appropriately considered as a unit. These are just some specially specified examples. In this application, in a similar manner, all possible combinations of numerical values ​​between the listed minimum and maximum values ​​are considered to have been disclosed.

[0151] It should be noted that the embodiments described above are only used to explain the present invention and do not constitute any limitation to the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than restrictive words. The present invention may be modified as specified within the scope of the claims of the present invention, and the present invention may be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein, on the contrary, the present invention can be extended to all other methods and applications with the same functions.

Claims

1. A supported catalyst comprising a carrier and an active component, wherein: The active component is selected from at least one of ruthenium, platinum and palladium; The carrier is amino-modified modified silicon dioxide, and the content of nitrogen in the carrier is 5-15wt%.

2. The supported catalyst according to claim 1, characterized in that The specific surface area of ​​the supported catalyst is 100 to 700 m 2 / g; and / or, the active component has a grain size of 0.5 to 5 nm; And / or, the dispersion degree of the active component is 50-96%.

3. The supported catalyst according to claim 1 or 2, characterized in that The mass ratio of the active component to the carrier is (0.1-10):100, preferably (0.1-5):100, and more preferably (0.5-5):

100.

4. A method for preparing a supported type as claimed in any one of claims 1 to 3, comprising the steps of: S1, providing a catalyst precursor containing an active component source and the carrier; S2. calcining the catalyst precursor to obtain the supported catalyst.

5. The preparation method according to claim 4, characterized in that: In step S1, the active component source is selected from one or more of ruthenium nitrosyl nitrate, ruthenium chloride, ruthenium acetylacetonate, ruthenium nitrate, ammonium hexachlororuthenate, platinum nitrate, chloroplatinic acid solution, platinum tetrachloride, platinum acetylacetonate, ammonium chloroplatinate, tetraammonium dichloroplatinum, palladium chloride, palladium nitrate, ammonium chloropalladate, palladium acetate and di(acetylacetonate)palladium; And / or, in step S2, the conditions of the calcination treatment include: a temperature of 200°C to 600°C, preferably 200°C to 400°C; and a time of 1 to 12 hours, preferably 2 to 8 hours.

6. The preparation method according to claim 4 or 5, characterized in that: The preparation of the carrier comprises the following steps: S101, subjecting a first reaction solution containing silicon dioxide, an amino modifier and a solvent I to a first reaction to obtain a reaction solution I; S102, performing solid-liquid separation on the reaction solution I, and optionally washing and drying the separated solid phase in sequence to obtain the amino-modified modified silica.

7. The preparation method according to any one of claims 4 to 6, characterized in that: In step S101, the silicon dioxide is selected from one or more of fumed silicon dioxide, alkaline silica sol, acidic silica sol, and synthetic silicon dioxide; And / or, in step S101, the amino modifier is selected from at least one of silane coupling agent KH550, 6-aminocaproic acid and 4-aminobutyric acid; And / or, in step S101, the solvent I is water and / or C1-C4 alcohol; preferably, the mass ratio of water to C1-C4 alcohol in the solvent I is (0-2):1, preferably (0-1):1; And / or, in step S101, the mass ratio of the silicon dioxide to the amino modifier is 1:(0.1-10), preferably 1:(0.2-5); And / or, in step S101, the mass ratio of the silicon dioxide to the solvent I is 1:(5-500), preferably 1:(10-300); And / or, in step S101, the reaction conditions of the first reaction include: temperature of 40°C to 120°C, preferably 40°C to 100°C; time of 2 to 72 hours, preferably 6 to 48 hours.

8. A method for preparing carbon monoxide by hydrogenating carbon dioxide, comprising the steps of: subjecting carbon dioxide to a hydrogenation reaction in the presence of hydrogen, carbon dioxide and a catalyst; wherein: The catalyst is a supported catalyst according to any one of claims 1 to 3 or a supported catalyst obtained by the preparation method according to any one of claims 4 to 7.

9. The method according to claim 8, characterized in that The molar ratio of hydrogen to carbon dioxide is 3 to 4:1; And / or, the conditions of the hydrogenation reaction include: reaction temperature of 160°C to 360°C; preferably 180°C to 320°C; pressure of 0.1 to 3 MPa, preferably 0.1 to 2.5 MPa; and / or, the space velocity of hydrogen and carbon dioxide is 2000~30000NL·kg -1 ·h -1 .

10. The method according to claim 8 or 9, characterized in that: Before the hydrogenation reaction, the catalyst is activated; the conditions of the activation treatment include: The activation atmosphere is hydrogen, carbon monoxide or synthesis gas; wherein the molar ratio of hydrogen to carbon monoxide in the synthesis gas is (1-1000):1, preferably (2-500):1; The activation pressure is 0.1 to 3 MPa, preferably 0.1 to 2 MPa; The activation temperature is 180°C to 500°C, preferably 200°C to 400°C.

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