Low-temperature methanol synthesis catalyst prepared by sputtering method and preparation method and application thereof

Abstract

The invention relates to the field of methanol synthesis, in particular to a low-temperature methanol synthesis catalyst prepared by a sputtering method and a preparation method and application thereof. The low-temperature methanol synthesis catalyst comprises a carrier and active metal fixed on the carrier through a sputtering method. The catalyst has excellent catalytic activity and good stability. The preparation process of the catalyst is simple to operate, efficient, practical, stable and high in repeatability. The catalyst can be used for directly converting synthesis gas into methanol under a low-temperature condition.

Description

Technical Field

[0001] The present invention relates to the field of methanol synthesis, and in particular to a low-temperature methanol synthesis catalyst prepared by a sputtering method, and a preparation method and application thereof. Background Art

[0002] In the chemical industry, methanol is an important raw material, usually used to prepare chemicals such as formaldehyde, acetic acid, and methacrylic acid. In addition, methanol has also been widely studied as a hydrogen supply energy carrier for fuel cells. The technology of directly preparing methanol from synthesis gas has also flourished in recent years, and the most critical part is the research and development of efficient catalysts.

[0003] In industry, catalysts for direct preparation of methanol from synthesis gas need to maintain high conversion, high selectivity and high stability under long-term high-temperature operation. Cu-containing catalysts can show higher activity in methanol synthesis reactions, among which CuZn catalysts have been widely studied. Compared with the impregnation method, the co-precipitation method can show higher activity because Cu and Zn are mixed with each other at the molecular level. Usually, when the Cu content is 40%-60%, the methanol synthesis yield is the highest. Zn acts as a carrier to make Cu highly dispersed, inhibit the sintering of copper particles and thus extend the service life of the catalyst.

[0004] The reaction of synthesizing methanol from synthesis gas is a reaction in which the number of molecules decreases and is accompanied by intense heat release. In thermodynamics, the lower the temperature and the higher the pressure, the more favorable it is for the reaction. Therefore, in order to efficiently synthesize methanol, removing the heat of reaction is also an important research topic. The current process is carried out in a fixed bed reactor using a Cu catalyst under reaction conditions of 250℃-300℃ and 5MPa-10MPa. Therefore, it is difficult to remove the heat of reaction, and the equilibrium conversion rate is 20%-30% under strict temperature control. In addition, recollecting the unreacted gas will also increase the operating cost of the reaction.

[0005] Therefore, the prior art still needs to be improved and developed. Summary of the invention

[0006] In view of the above-mentioned deficiencies in the prior art, the object of the present invention is to provide a low-temperature methanol synthesis catalyst prepared by sputtering and a preparation method and application thereof, aiming to solve the problem that the existing catalysts cannot directly convert synthesis gas into methanol under low temperature conditions.

[0007] The technical solution of the present invention is as follows:

[0008] A first aspect of the present invention provides a low-temperature methanol synthesis catalyst prepared by a sputtering method, wherein the catalyst comprises a carrier and an active metal fixed on the carrier by a sputtering method.

[0009] Optionally, the carrier is prepared by a coprecipitation method;

[0010] The carrier is selected from one of a CuZn carrier, a ZnAl carrier and a CeCr carrier;

[0011] The active metal is selected from one of Cu, Pd and Pt;

[0012] The mass ratio of the carrier to the active metal is in the range of 0.1% to 10%.

[0013] A second aspect of the present invention provides a method for preparing the low-temperature methanol synthesis catalyst according to the present invention, wherein the preparation method comprises:

[0014] Step 1, preparing a carrier;

[0015] Step 2: placing the carrier into a sputtering device, installing a target material, and sputtering the active metal on the target material onto the carrier to obtain the low-temperature methanol synthesis catalyst.

[0016] Optionally, the step 1 specifically includes:

[0017] Step 11, preparing an aqueous solution of a soluble metal salt, recorded as salt solution A; preparing an alkaline solution, recorded as alkaline solution B;

[0018] Step 12, adding the salt solution A and the alkaline solution B into water and reacting under stirring;

[0019] Step 13: After the reaction is completed, stop stirring and age the precipitate obtained by the reaction;

[0020] Step 14: After aging, the precipitate is purified and calcined to obtain the carrier.

[0021] Optionally, in step 11, the alkali in the alkaline solution is selected from one or more of ammonium carbonate, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, sodium hydroxide, and potassium hydroxide;

[0022] In step 12, the reaction temperature is 30°C-90°C; the pH value during the reaction is maintained between 3-11;

[0023] In the step 13, the aging time is 2h-24h;

[0024] In the step 14, the calcination temperature is 350° C.-550° C., and the calcination time is 3 h-8 h.

[0025] Optionally, the step 2 specifically includes:

[0026] Step 21, placing the carrier into the bottom of a hexagonal barrel of a barrel sputtering device, and installing a target material;

[0027] Step 22: Reduce the pressure of the sputtering device to 9.9×10 -4 Pa, and then an inert gas is introduced into the sputtering device until the pressure reaches 1 Pa, and the active metal on the target is sputtered onto the carrier to obtain the low-temperature methanol synthesis catalyst.

[0028] Optionally, in step 21, the target material is a metal target material or a metal oxide target material;

[0029] In the step 22, the sputtering time is 5 min-720 min; and the RF output is 100 W-400 W.

[0030] The third aspect of the present invention provides an application of the low-temperature methanol synthesis catalyst prepared by the sputtering method described in the present invention in catalyzing the preparation of methanol from synthesis gas.

[0031] A fourth aspect of the present invention provides a method for preparing methanol from synthesis gas, comprising the steps of:

[0032] The low-temperature methanol synthesis catalyst prepared by the sputtering method of the present invention is crushed, placed in a reaction kettle, and a solvent is added;

[0033] After introducing synthesis gas into the reactor to replace the air, the pressure in the reactor is increased to a predetermined pressure with the synthesis gas, and stirring is started at the same time. Then, the temperature in the reactor is increased to a predetermined temperature and maintained for a predetermined time to obtain methanol.

[0034] Optionally, the mass of the catalyst is 0.5-5 g; the volume of the solvent is 10-50 mL; the solvent is butanol; the reaction pressure is 2-5 MPa; the predetermined temperature is 150-190° C.; the predetermined time is 20 h; and the stirring speed is 2000 rpm.

[0035] Beneficial effects: The low-temperature methanol synthesis catalyst prepared by the sputtering method of the present invention has excellent catalytic activity, good hydrothermal stability and stable service life. The sputtering method of the present invention has a simple principle and is easy to operate.

[0036] The sputtering device used in the present invention can fix the catalytically active components on the target material (such as a metal target material or a metal oxide target material) on the carrier in the form of atoms or molecules by applying voltage. After sputtering, the catalytically active component particles are small and the interaction force between the catalytically active component and the carrier is strong. This not only improves the catalytic activity of the low-temperature methanol synthesis catalyst, but also improves the stability of the low-temperature methanol synthesis catalyst.

[0037] The sputtering device used in the present invention can change the dispersion of the catalytic active components from the target material on the carrier by adjusting the radio frequency output. Compared with the traditional impregnation method, the dispersion of the catalytic active components is higher and the anti-sintering ability is stronger.

[0038] Compared with the catalyst prepared by the impregnation method, the catalyst prepared by the sputtering method can directly convert synthesis gas into methanol under low temperature conditions, and the catalyst has higher catalytic activity, higher conversion rate and higher methanol selectivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 A schematic structural diagram of a sputtering device provided in an embodiment of the present invention.

[0040] Figure 2 A process flow chart for low-temperature synthesis of methanol from synthesis gas provided in an embodiment of the present invention.

[0041] Figure 3 The XRD spectrum of the catalyst of the present invention is shown in FIG. DETAILED DESCRIPTION

[0042] The present invention provides a low-temperature methanol synthesis catalyst prepared by a sputtering method and a preparation method and application thereof. In order to make the purpose, technical scheme and effect of the present invention clearer and more specific, the present invention is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0043] Sputtering refers to a film-forming technology that introduces an inert gas (mainly Ar) into a high vacuum, applies voltage to the target material (plate-shaped material), generates a grating discharge, and causes the particles on the target material to violently eject and quickly adhere and deposit on the surface of the substrate. Sputtering is different from vacuum evaporation by heating film formation. It is produced by applying voltage, so the film-forming particles have high energy, strong adhesion, small film-forming particles, and strong film quality. Since the sputtering process is stable, the film thickness and film quality can be controlled with high precision. Film formation can be achieved without changing the composition ratio of alloys and compounds. In addition, even metals with high melting points can be formed into films. The active metal film formed on the carrier by sputtering can also be used for catalyst preparation. The catalyst prepared by the sputtering method is different from the traditional impregnation method. Sputtering can directly fix atoms on the carrier surface in a directional manner, avoiding the drying, roasting, ultrasonic vibration and other processes in the traditional impregnation method. In addition, during the reaction process, the sputtering method can also completely avoid the aggregation of active species, effectively extending the service life of the catalyst.

[0044] Based on this, an embodiment of the present invention provides a low-temperature methanol synthesis catalyst prepared by a sputtering method, wherein the catalyst comprises a carrier and an active metal fixed on the carrier by a sputtering method.

[0045] The low-temperature methanol synthesis catalyst of the embodiment of the present invention has excellent catalytic activity, good stability and stable service life. The preparation process of the low-temperature methanol synthesis catalyst is simple to operate, efficient and practical, and the preparation process is stable and highly repeatable. The low-temperature methanol synthesis catalyst can directly convert synthesis gas into methanol under low temperature conditions.

[0046] In one embodiment, the carrier is prepared by a co-precipitation method.

[0047] In one embodiment, the carrier is selected from one of a CuZn carrier, a ZnAl carrier, a CeCr carrier, etc., but is not limited thereto.

[0048] In one embodiment, the active metal is selected from one of Cu, Pd, Pt and the like, but is not limited thereto.

[0049] In one embodiment, the mass ratio of the carrier to the active metal is in the range of 0.1%-10%, such as 0.1%, 1%, 3%, 5%, 6%, 8%, 9%, 10%, etc., but not limited thereto.

[0050] An embodiment of the present invention provides a method for preparing the low-temperature methanol synthesis catalyst as described above, wherein the preparation method comprises:

[0051] Step 1, preparing a carrier;

[0052] Step 2: placing the carrier into a sputtering device, installing a target material, and sputtering the active metal on the target material onto the carrier to obtain the low-temperature methanol synthesis catalyst.

[0053] In the embodiment of the present invention, after the active metal is loaded on the carrier by the sputtering method, a low-temperature methanol synthesis catalyst is obtained, and the low-temperature methanol synthesis catalyst can be used for low-temperature methanol synthesis.

[0054] In one embodiment, the step 1 specifically includes:

[0055] Step 11, preparing an aqueous solution of a soluble metal salt, recorded as salt solution A; preparing an alkaline solution, recorded as alkaline solution B;

[0056] Step 12, adding the salt solution A and the alkaline solution B into water and reacting under stirring;

[0057] Step 13: After the reaction is completed, stop stirring and age the precipitate obtained by the reaction;

[0058] Step 14: After aging, the precipitate is purified and calcined to obtain the carrier.

[0059] Furthermore, in step 11, the salt solution A includes two soluble metal salts, and the molar ratio of the two soluble metal salts is 0.01-99, such as 0.01, 1, 2, 50, 99, etc.; the alkali in the alkaline solution is selected from one or more of ammonium carbonate, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, sodium hydroxide, and potassium hydroxide.

[0060] Furthermore, in step 12, the reaction temperature is 30°C-90°C (such as 30°C, 60°C, 70°C, 80°C, 90°C, etc.); by adjusting the feed rates of salt solution A and alkaline solution B, the pH of the reaction process is maintained between 3-11.

[0061] Furthermore, in step 13, the aging time is 2 h to 24 h, such as 2 h, 4 h, 5 h, 8 h, 10 h, 12 h, 20 h, 24 h, etc.

[0062] Furthermore, in step 14, the step of purifying the precipitate specifically includes: filtering the precipitate to obtain a filter cake; washing the filter cake with water, and drying the washed filter cake. Furthermore, the drying temperature is 100° C.-120° C., and the drying time is 10-15 hours, such as 12 hours.

[0063] Further, in step 14, the calcination temperature is 350°C-550°C (such as 350°C, 400°C, 450°C, 500°C, 550°C, etc.), and the calcination time is 3h-8h (such as 3h, 4h, 5h, 6h, 7h, 8h, etc.). Furthermore, the temperature is heated to 350°C-550°C at a rate of 1-10°C / min (such as 5°C / min).

[0064] In one embodiment, in combination Figure 1 As shown, the step 2 specifically includes:

[0065] Step 21, placing the carrier into the bottom of a hexagonal barrel of a barrel sputtering device, and installing a target material;

[0066] Step 22: Reduce the pressure of the sputtering device to 9.9×10 -4 Pa, and then an inert gas (such as high-purity argon) is introduced into the sputtering device until the pressure reaches 1 Pa, and the active metal on the target is sputtered onto the carrier to obtain the low-temperature methanol synthesis catalyst.

[0067] The sputtering device used in the embodiment of the present invention can change the dispersion of the catalytically active components from the target material on the carrier by adjusting the radio frequency output.

[0068] Compared with the traditional impregnation method, the sputtering method can completely avoid the aggregation of catalytic active components on the carrier, the catalytic active components are more dispersed, and the anti-sintering ability is stronger, thereby effectively extending the service life of the catalyst. In addition, unlike the traditional impregnation method, the sputtering method can directly fix atoms on the carrier surface, avoiding the drying, roasting, ultrasonic vibration and other processes in the traditional impregnation method.

[0069] Furthermore, in step 21, the mass of the carrier is 0.1g-100g, such as 0.1g, 1g, 10g, 50g, 70g, 90g, 100g, etc.; the target material is a metal target material or a metal oxide target material.

[0070] Furthermore, in step 22, the sputtering time is 5 min-720 min, such as 5 min, 30 min, 60 min, 120 min, 200 min, 240 min, 500 min, 650 min, 720 min, etc.; the RF output is 100 W-400 W, such as 100 W, 150 W, 200 W, 250 W, 300 W, 350 W, 400 W, etc.

[0071] An embodiment of the present invention provides an application of the low-temperature methanol synthesis catalyst prepared by the sputtering method as described above in catalyzing the preparation of methanol from synthesis gas.

[0072] The mechanism of the catalytic reaction is as follows: (1) CO is first converted into CO via the reverse water gas reaction. 2 ; (2) CO 2 Hydrogenation generates formate species; (3) the formate species reacts with butanol to form butyl formate and water; (4) butyl formate is hydrogenated to form methanol and butanol.

[0073] It should be noted that before the catalyst is used to catalyze the synthesis gas to produce methanol, the catalyst needs to be reduced offline. After the offline reduction is completed, the catalyst needs to be passivated.

[0074] This is because before catalytic synthesis gas to produce methanol, part of the Cu in the catalyst, such as the Cu-based catalyst, needs to be reduced to zero valence to ensure the activity of the catalyst. Since the reaction device is a slurry bed and solvent is added during the reaction, the online reduction method cannot be used, and offline reduction is required.

[0075] After the offline reduction is completed, if the catalyst is taken out directly, the reduced catalyst will be directly and completely exposed to the air. The high oxygen concentration in the air will quickly oxidize the catalyst. Passivation treatment of the reduced catalyst can prevent the catalyst from being oxidized quickly.

[0076] The catalyst reduction process is an offline reduction process. The specific process can be: in an atmosphere containing hydrogen and nitrogen, keep the temperature at 220°C for 10 hours. After the reduction is completed, wait for the temperature to drop to room temperature, then introduce nitrogen for 1 hour, and finally use 1% O diluted with nitrogen. 2 Perform passivation treatment.

[0077] Combination Figure 2 As shown, an embodiment of the present invention provides a method for preparing methanol from synthesis gas, which includes the steps of:

[0078] The low-temperature methanol synthesis catalyst prepared by the sputtering method described in the embodiment of the present invention is crushed, placed in a reaction kettle, and a solvent is added;

[0079] After introducing synthesis gas into the reactor to replace the air, the pressure in the reactor is increased to a predetermined pressure with the synthesis gas, and stirring is started at the same time. Then, the temperature in the reactor is increased to a predetermined temperature and maintained for a predetermined time to obtain methanol.

[0080] In one embodiment, the catalyst mass is 0.5-5g (such as 1g); the solvent volume is 10-50mL (such as 40mL); the solvent is butanol; the reaction pressure is 2-5MPa (such as 3MPa); the predetermined temperature is 150-190°C (such as 170°C); the predetermined time is 20h; and the stirring speed is 2000rpm.

[0081] In order to solve the problem of removing the reaction exothermic heat, the embodiment of the present invention proposes a process for synthesizing methanol at low temperature by a liquid phase fluidized bed using a solvent with a large heat capacity. This low temperature methanol synthesis process can not only effectively remove the reaction exothermic heat, but also reduce the manufacturing cost of the reaction equipment.

[0082] The present invention uses a low-temperature methanol synthesis catalyst prepared by a sputtering method as a catalyst in a liquid phase fluidized bed low-temperature methanol synthesis process. The low-temperature methanol synthesis catalyst prepared by a sputtering method in the present invention has excellent catalytic activity, good hydrothermal stability and a stable service life.

[0083] The present invention is further described in detail below through several specific embodiments.

[0084] Example 1

[0085] Weigh 40.6 g Cu(NO 3 ) 2 ·3H 2 O and 50 g Zn(NO 3 ) 2 6H 2 O (Cu / Zn molar ratio is 1) was dissolved in 300 mL of deionized water and stirred to completely dissolve, which was recorded as salt solution A. 1 mol / L Na2 CO 3 Solution, recorded as alkaline solution B. Heat a beaker filled with 100mL of deionized water in a water bath. After the temperature rises to 60°C, drip salt solution A and alkaline solution B at the same time and start stirring. In this process, the pH is controlled between 6.5-7.5 by adjusting the feed rate of salt solution A and alkaline solution B, and the water bath temperature is controlled at 60°C. After salt solution A is completely dripped in, stop dripping alkaline solution B and stop stirring. After the precipitate is aged at a water bath temperature of 60°C for 4h, the precipitate is filtered and washed, and then dried at 100°C for 12h. The precipitate is then placed in a muffle furnace for calcination, heated to 400°C at a rate of 5°C / min and maintained for 4h. The CuZn carrier is obtained after calcination.

[0086] 5.0 g of CuZn carrier was placed in the bottom of the hexagonal barrel of the barrel sputtering device, and the Cu target was installed. Then, the pressure of the device was reduced to 9.9 × 10 -4 Pa. Subsequently, high-purity argon (99.995%) was introduced into the device until the pressure reached about 1 Pa, and the CuZn carrier was sputtered. The RF output was 150 W and the sputtering time was 30 min. Subsequently, 1% O 2 Gas is removed from the sputtering device to return the pressure to normal pressure, and the catalyst is removed from the sputtering device.

[0087] The catalyst reduction process is offline reduction. The specific process is: 2 and 95% N 2 In an atmosphere of , the temperature was raised to 220 ° C for 1 h and maintained for 10 h. After the reduction was completed, the temperature was allowed to drop to room temperature, and then nitrogen was introduced for 1 h, and finally 1% O diluted with nitrogen was used. 2 Unless otherwise specified, % refers to volume percentage.

[0088] Example 2

[0089] Weigh 50g Zn(NO 3 ) 2 6H 2 O and 31.5g Al(NO 3 ) 3 9H 2 O (Zn / Al molar ratio is 2) was dissolved in 300 mL of deionized water and stirred to completely dissolve, which was recorded as salt solution A. 1 mol / L Na 2 CO 3Solution, recorded as alkaline solution B. Heat a beaker filled with 10mL of deionized water in a water bath. After the temperature rises to 90°C, drip salt solution A and alkaline solution B at the same time and start stirring. In this process, the pH is controlled between 7.5-8.5 by adjusting the feed rate of salt solution A and alkaline solution B, and the water bath temperature is controlled at 90°C. After salt solution A is completely dripped in, stop dripping alkaline solution B and stop stirring. After aging the precipitate at a water bath temperature of 90°C for 2h, the precipitate is filtered and washed, and then dried at 120°C for 12h. The precipitate is then placed in a muffle furnace for calcination, heated to 350°C at a rate of 5°C / min and maintained for 3h. After calcination, a ZnAl carrier is obtained.

[0090] 0.1 g of ZnAl carrier was placed in the bottom of the hexagonal barrel of the barrel sputtering device, and a Pd target was installed. Then, the pressure of the device was reduced to 9.9 × 10 -4 Pa. Subsequently, high-purity argon (99.995%) was introduced into the device until the pressure reached about 1 Pa, and the ZnAl carrier was sputtered. The RF output was 100 W and the sputtering time was 5 min. Subsequently, 1% O 2 Gas is removed from the sputtering device to return the pressure to normal pressure, and the catalyst is removed from the sputtering device.

[0091] The catalyst reduction process is offline reduction. The specific process is: 2 and 95% N 2 In an atmosphere of , the temperature was raised to 220 ° C for 1 h and maintained for 10 h. After the reduction was completed, the temperature was allowed to drop to room temperature, and then nitrogen was introduced for 1 h, and finally 1% O diluted with nitrogen was used. 2 Perform passivation treatment.

[0092] Example 3

[0093] Weigh 73g Ce(NO 3 ) 2 6H 2 O and 1.3 g Cr(NO 3 ) 3 9H 2 O (Ce / Cr molar ratio is 50) was dissolved in 300 mL of deionized water and stirred to completely dissolve, which was recorded as salt solution A. 1 mol / L Na 2 CO 3Solution, recorded as alkaline solution B. Heat a beaker filled with 300mL of deionized water in a water bath. After the temperature rises to 40°C, drip salt solution A and alkaline solution B at the same time and start stirring. In this process, the pH is controlled between 7.5-8.5 by adjusting the feed rate of salt solution A and alkaline solution B, and the water bath temperature is controlled at 40°C. After salt solution A is completely dripped in, stop dripping alkaline solution B and stop stirring. After the precipitate is aged at a water bath temperature of 40°C for 12h, the precipitate is filtered and washed, and then dried at 120°C for 12h. The precipitate is then placed in a muffle furnace for calcination, heated to 450°C at a rate of 5°C / min and maintained for 6h. After calcination, a CeCr carrier is obtained.

[0094] 50 g of CeCr carrier was placed in the bottom of the hexagonal barrel of the barrel sputtering device, and a Pt target was installed. Then, the pressure of the device was reduced to 9.9 × 10 -4 Pa. Subsequently, high-purity argon (99.995%) was introduced into the device until the pressure reached about 1 Pa, and the CeCr carrier was sputtered. The RF output was 200 W and the sputtering time was 60 min. Subsequently, 1% O 2 Gas is removed from the sputtering device to return the pressure to normal pressure, and the catalyst is removed from the sputtering device.

[0095] The catalyst reduction process is offline reduction. The specific process is: 2 and 95% N 2 In an atmosphere of , the temperature was raised to 220 ° C for 1 h and maintained for 10 h. After the reduction was completed, the temperature was allowed to drop to room temperature, and then nitrogen was introduced for 1 h, and finally 1% O diluted with nitrogen was used. 2 Perform passivation treatment.

[0096] In order to highlight the effect of sputtering different metals on catalytic performance under the same preparation conditions, comparative examples 1-2 are provided. That is, comparative examples 1-2 use the same carrier as Example 1, and the other process flows are also exactly the same, the only difference is that the sputtered metals are different, in order to explore the effect of sputtering different metals on catalytic performance.

[0097] Comparative Example 1

[0098] Weigh 40.6 g Cu(NO 3 ) 2 ·3H 2 O and 50 g Zn(NO 3 ) 2 6H 2 O (Cu / Zn molar ratio is 1) was dissolved in 300 mL of deionized water and stirred to completely dissolve, which was recorded as salt solution A. 1 mol / L Na 2 CO 3Solution, recorded as alkaline solution B. Heat a beaker filled with 100mL of deionized water in a water bath. After the temperature rises to 60°C, drip salt solution A and alkaline solution B at the same time and start stirring. In this process, the pH is controlled between 6.5-7.5 by adjusting the feed rate of salt solution A and alkaline solution B, and the water bath temperature is controlled at 60°C. After salt solution A is completely dripped in, stop dripping alkaline solution B and stop stirring. After the precipitate is aged at a water bath temperature of 60°C for 4h, the precipitate is filtered and washed, and then dried at 100°C for 12h. The precipitate is then placed in a muffle furnace for calcination, heated to 400°C at a rate of 5°C / min and maintained for 4h. The CuZn carrier is obtained after calcination.

[0099] 5.0 g of CuZn carrier was placed in the bottom of the hexagonal barrel of the barrel sputtering device, and a Pd target was installed. Then, the pressure of the device was reduced to 9.9 × 10 -4 Pa. Subsequently, high-purity argon (99.995%) was introduced into the device until the pressure reached about 1 Pa, and the CuZn carrier was sputtered. The RF output was 150 W and the sputtering time was 30 min. Subsequently, 1% O 2 Gas is removed from the sputtering device to return the pressure to normal pressure, and the catalyst is removed from the sputtering device.

[0100] The catalyst reduction process is offline reduction. The specific process is: 2 and 95% N 2 In an atmosphere of , the temperature was raised to 220 ° C for 1 h and maintained for 10 h. After the reduction was completed, the temperature was allowed to drop to room temperature, and then nitrogen was introduced for 1 h, and finally 1% O diluted with nitrogen was used. 2 Perform passivation treatment.

[0101] Comparative Example 2

[0102] Weigh 40.6 g Cu(NO 3 ) 2 ·3H 2 O and 50 g Zn(NO 3 ) 2 6H 2 O (Cu / Zn molar ratio is 1) was dissolved in 300 mL of deionized water and stirred to completely dissolve, which was recorded as salt solution A. 1 mol / L Na 2 CO 3Solution, recorded as alkaline solution B. Heat a beaker filled with 100mL of deionized water in a water bath. After the temperature rises to 60°C, drip salt solution A and alkaline solution B at the same time and start stirring. In this process, the pH is controlled between 6.5-7.5 by adjusting the feed rate of salt solution A and alkaline solution B, and the water bath temperature is controlled at 60°C. After salt solution A is completely dripped in, stop dripping alkaline solution B and stop stirring. After the precipitate is aged at a water bath temperature of 60°C for 4h, the precipitate is filtered and washed, and then dried at 100°C for 12h. The precipitate is then placed in a muffle furnace for calcination, heated to 400°C at a rate of 5°C / min and maintained for 4h. The CuZn carrier is obtained after calcination.

[0103] 5.0 g of CuZn carrier was placed in the bottom of the hexagonal barrel of the barrel sputtering device, and a Pt target was installed. Then, the pressure of the device was reduced to 9.9 × 10 -4 Pa. Subsequently, high-purity argon (99.995%) was introduced into the device until the pressure reached about 1 Pa, and the CuZn carrier was sputtered. The RF output was 150 W and the sputtering time was 30 min. Subsequently, 1% O 2 Gas is removed from the sputtering device to return the pressure to normal pressure, and the catalyst is removed from the sputtering device.

[0104] The catalyst reduction process is offline reduction. The specific process is: 2 and 95% N 2 In an atmosphere of , the temperature was raised to 220 ° C for 1 h and maintained for 10 h. After the reduction was completed, the temperature was allowed to drop to room temperature, and then nitrogen was introduced for 1 h, and finally 1% O diluted with nitrogen was used. 2 Perform passivation treatment.

[0105] Comparative Example 3

[0106] Weigh 40.6 g Cu(NO 3 ) 2 ·3H 2 O and 50 g Zn(NO 3 ) 2 6H 2 O (Cu / Zn molar ratio is 1) was dissolved in 300 mL of deionized water and stirred to completely dissolve, which was recorded as salt solution A. 1 mol / L Na 2 CO 3Solution, recorded as alkaline solution B. Heat a beaker filled with 100mL of deionized water in a water bath. After the temperature rises to 60°C, drip salt solution A and alkaline solution B at the same time and start stirring. In this process, the pH is controlled between 6.5-7.5 by adjusting the feed rate of salt solution A and alkaline solution B, and the water bath temperature is controlled at 60°C. After salt solution A is completely dripped in, stop dripping alkaline solution B and stop stirring. After the precipitate is aged at a water bath temperature of 60°C for 4h, the precipitate is filtered and washed, and then dried at 100°C for 12h. The precipitate is then placed in a muffle furnace for calcination, heated to 400°C at a rate of 5°C / min and maintained for 4h. The CuZn carrier is obtained after calcination.

[0107] The catalyst reduction process is offline reduction. The specific process is: 2 and 95% N 2 In an atmosphere of , the temperature was raised to 220 ° C for 1 h and maintained for 10 h. After the reduction was completed, the temperature was allowed to drop to room temperature, and then nitrogen was introduced for 1 h, and finally 1% O diluted with nitrogen was used. 2 Perform passivation treatment.

[0108] Comparative Example 4

[0109] Weigh 40.6 g Cu(NO 3 ) 2 ·3H 2 O and 50 g Zn(NO 3 ) 2 6H 2 O (Cu / Zn molar ratio is 1) was dissolved in 300 mL of deionized water and stirred to completely dissolve, which was recorded as salt solution A. 1 mol / L Na 2 CO 3 Solution, recorded as alkaline solution B. Heat a beaker filled with 100mL of deionized water in a water bath. After the temperature rises to 60°C, drip salt solution A and alkaline solution B at the same time and start stirring. In this process, the pH is controlled between 6.5-7.5 by adjusting the feed rate of salt solution A and alkaline solution B, and the water bath temperature is controlled at 60°C. After salt solution A is completely dripped in, stop dripping alkaline solution B and stop stirring. After the precipitate is aged at a water bath temperature of 60°C for 4h, the precipitate is filtered and washed, and then dried at 100°C for 12h. The precipitate is then placed in a muffle furnace for calcination, heated to 400°C at a rate of 5°C / min and maintained for 4h. The CuZn carrier is obtained after calcination.

[0110] The same amount of Cu as that sputtered in Example 1 was impregnated onto the CuZn carrier using a conventional impregnation method.

[0111] The catalyst reduction process is offline reduction. The specific process is: 2 and 95% N2 In an atmosphere of , the temperature was raised to 220 ° C for 1 h and maintained for 10 h. After the reduction was completed, the temperature was allowed to drop to room temperature, and then nitrogen was introduced for 1 h, and finally 1% O diluted with nitrogen was used. 2 Perform passivation treatment.

[0112] Comparative Example 5

[0113] Weigh 40.6 g Cu(NO 3 ) 2 ·3H 2 O and 50 g Zn(NO 3 ) 2 6H 2 O (Cu / Zn molar ratio is 1) was dissolved in 300 mL of deionized water and stirred to completely dissolve, which was recorded as salt solution A. 1 mol / L Na 2 CO 3 Solution, recorded as alkaline solution B. Heat a beaker filled with 100mL of deionized water in a water bath. After the temperature rises to 60°C, drip salt solution A and alkaline solution B at the same time and start stirring. In this process, the pH is controlled between 6.5-7.5 by adjusting the feed rate of salt solution A and alkaline solution B, and the water bath temperature is controlled at 60°C. After salt solution A is completely dripped in, stop dripping alkaline solution B and stop stirring. After the precipitate is aged at a water bath temperature of 60°C for 4h, the precipitate is filtered and washed, and then dried at 100°C for 12h. The precipitate is then placed in a muffle furnace for calcination, heated to 400°C at a rate of 5°C / min and maintained for 4h. The CuZn carrier is obtained after calcination.

[0114] 5.0 g of CuZn carrier was placed in the bottom of the hexagonal barrel of the barrel sputtering device, and the Cu target was installed. Then, the pressure of the device was reduced to 9.9 × 10 -4 Pa. Subsequently, high-purity argon (99.995%) was introduced into the device until the pressure reached about 1 Pa, and the CuZn carrier was sputtered. The RF output was 200 W and the sputtering time was 30 min. Subsequently, 1% O 2 Gas is removed from the sputtering device to return the pressure to normal pressure, and the catalyst is removed from the sputtering device.

[0115] The catalyst reduction process is offline reduction. The specific process is: 2 and 95% N 2 In an atmosphere of , the temperature was raised to 220 ° C for 1 h and maintained for 10 h. After the reduction was completed, the temperature was allowed to drop to room temperature, and then nitrogen was introduced for 1 h, and finally 1% O diluted with nitrogen was used. 2 Perform passivation treatment.

[0116] Comparative Example 6

[0117] Weigh 40.6 g Cu(NO 3 ) 2 ·3H 2 O and 50 g Zn(NO 3 ) 2 6H 2 O (Cu / Zn molar ratio is 1) was dissolved in 300 mL of deionized water and stirred to completely dissolve, which was recorded as salt solution A. 1 mol / L Na 2 CO 3 Solution, recorded as alkaline solution B. Heat a beaker filled with 100mL of deionized water in a water bath. After the temperature rises to 60°C, drip salt solution A and alkaline solution B at the same time and start stirring. In this process, the pH is controlled between 6.5-7.5 by adjusting the feed rate of salt solution A and alkaline solution B, and the water bath temperature is controlled at 60°C. After salt solution A is completely dripped in, stop dripping alkaline solution B and stop stirring. After the precipitate is aged at a water bath temperature of 60°C for 4h, the precipitate is filtered and washed, and then dried at 100°C for 12h. The precipitate is then placed in a muffle furnace for calcination, heated to 400°C at a rate of 5°C / min and maintained for 4h. The CuZn carrier is obtained after calcination.

[0118] 5.0 g of CuZn carrier was placed in the bottom of the hexagonal barrel of the barrel sputtering device, and the Cu target was installed. Then, the pressure of the device was reduced to 9.9 × 10 -4 Pa. Subsequently, high-purity argon (99.995%) was introduced into the device until the pressure reached about 1 Pa, and the CuZn carrier was sputtered. The RF output was 300 W and the sputtering time was 30 min. Subsequently, 1% O 2 Gas is removed from the sputtering device to return the pressure to normal pressure, and the catalyst is removed from the sputtering device.

[0119] The catalyst reduction process is offline reduction. The specific process is: 2 and 95% N 2 In an atmosphere of , the temperature was raised to 220 ° C for 1 h and maintained for 10 h. After the reduction was completed, the temperature was allowed to drop to room temperature, and then nitrogen was introduced for 1 h, and finally 1% O diluted with nitrogen was used. 2 Perform passivation treatment.

[0120] The catalysts prepared in Example 1 (CuZn+Cu) and Comparative Example 3 (CuZn) and the reduced catalysts were subjected to XRD tests. The test results are as follows: Figure 3 As shown. Figure 3 It can be seen that both CuZn and CuZn+Cu catalysts show typical ZnO and CuO crystal phases, and after reduction, CuO is converted into metallic Cu.

[0121] The nine catalysts prepared in Examples 1-3 and Comparative Examples 1-6 were tested for their activities.

[0122] The activity of the catalyst was tested using a liquid phase fluidized bed reaction device, and the specific steps were as follows: the reduced catalysts prepared in Examples 1-3 and Comparative Examples 1-6 were crushed and placed in a reactor with a volume of 85 mL. 40 mL of butanol was then added as a solvent. After 1 MPa of synthesis gas was introduced into the reactor for three replacements, the pressure in the reactor was raised to 3 MPa with synthesis gas, and stirring was started with a stirring paddle. When the temperature in the reactor rose to 170°C, the reaction started.

[0123] Low-temperature methanol synthesis reaction conditions: catalyst mass 1g; solvent butanol; reaction pressure 3MPa; reaction temperature 170℃; reaction time 20h; stirring speed 2000rpm; synthesis gas volume ratio CO / CO 2 / Ar / H 2 =33 / 5.27 / 3.02 / 58.71. The catalyst activity test results are shown in Table 1.

[0124] Table 1. Catalyst activity test results

[0125]

[0126]

[0127] From the data in Table 1, it can be seen that in Example 1 and Comparative Examples 1-2 (CuZn carrier, sputtered Cu, Pd, Pt respectively), under the same other conditions, sputtered Cu can show the highest CO conversion rate and CO 2 The CO conversion rate, total carbon conversion rate and methanol selectivity of the samples of Examples 1-3 and Comparative Examples 1-2 and 5-6 (prepared by sputtering) are shown in Table 1. 2 The conversion rate, total carbon conversion rate and methanol selectivity are all higher than those of Comparative Example 4 (prepared by impregnation method), indicating that the catalyst prepared by sputtering method has higher catalytic activity, higher conversion rate and higher methanol selectivity. Comparing Example 1 with Comparative Examples 5 and 6, under the same other conditions, as the RF output gradually increases, the CO conversion rate shows a trend of first increasing and then decreasing, and the total carbon conversion rate and methanol selectivity gradually decrease.

[0128] In summary, the present invention provides a low-temperature methanol synthesis catalyst prepared by a sputtering method, and a preparation method and application thereof. The low-temperature methanol synthesis catalyst prepared by a sputtering method of the present invention has excellent catalytic activity, good hydrothermal stability and a stable service life. The preparation process of the low-temperature methanol synthesis catalyst is simple to operate, efficient and practical, and the preparation process is stable and highly repeatable. The low-temperature methanol synthesis catalyst can directly convert synthesis gas into methanol under low temperature conditions. Compared with the catalyst prepared by the impregnation method, the catalyst prepared by the sputtering method has higher catalytic activity, higher conversion rate, and higher methanol selectivity.

[0129] It should be understood that the application of the present invention is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A low-temperature methanol synthesis catalyst prepared by a sputtering method, characterized in that: The invention comprises a carrier and an active metal fixed on the carrier by a sputtering method.

2. The low-temperature methanol synthesis catalyst prepared by sputtering method according to claim 1, characterized in that: The carrier is prepared by a co-precipitation method; The carrier is selected from one of a CuZn carrier, a ZnAl carrier and a CeCr carrier; The active metal is selected from one of Cu, Pd and Pt; The mass ratio of the carrier to the active metal is in the range of 0.1% to 10%.

3. A method for preparing a low-temperature methanol synthesis catalyst according to any one of claims 1 to 2, characterized in that: The preparation method comprises: Step 1, preparing a carrier; Step 2: placing the carrier into a sputtering device, installing a target material, and sputtering the active metal on the target material onto the carrier to obtain the low-temperature methanol synthesis catalyst.

4. The method for preparing a low-temperature methanol synthesis catalyst according to claim 3, characterized in that: The step 1 specifically includes: Step 11, preparing an aqueous solution of a soluble metal salt, recorded as salt solution A; preparing an alkaline solution, recorded as alkaline solution B; Step 12, adding the salt solution A and the alkaline solution B into water and reacting under stirring; Step 13: After the reaction is completed, stop stirring and age the precipitate obtained by the reaction; Step 14: After aging, the precipitate is purified and calcined to obtain the carrier.

5. The method for preparing a low-temperature methanol synthesis catalyst according to claim 4, characterized in that: In the step 11, the alkali in the alkaline solution is selected from one or more of ammonium carbonate, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, sodium hydroxide, and potassium hydroxide; In step 12, the reaction temperature is 30°C-90°C; the pH value during the reaction is maintained between 3-11; In the step 13, the aging time is 2h-24h; In the step 14, the calcination temperature is 350° C.-550° C., and the calcination time is 3 h-8 h.

6. The method for preparing a low-temperature methanol synthesis catalyst according to claim 3, characterized in that: The step 2 specifically includes: Step 21, placing the carrier into the bottom of a hexagonal barrel of a barrel sputtering device, and installing a target material; Step 22: Reduce the pressure of the sputtering device to 9.9×10 -4 Pa, and then an inert gas is introduced into the sputtering device until the pressure reaches 1 Pa, and the active metal on the target is sputtered onto the carrier to obtain the low-temperature methanol synthesis catalyst.

7. The method for preparing a low-temperature methanol synthesis catalyst according to claim 6, characterized in that: In the step 21, the target material is a metal target material or a metal oxide target material; In the step 22, the sputtering time is 5 min-720 min; and the RF output is 100 W-400 W.

8. Use of the low-temperature methanol synthesis catalyst prepared by sputtering method according to any one of claims 1 to 2 in catalyzing the preparation of methanol from synthesis gas.

9. A method for preparing methanol from synthesis gas, characterized in that: Includes steps: The low-temperature methanol synthesis catalyst prepared by the sputtering method according to any one of claims 1 to 2 is crushed, placed in a reaction kettle, and a solvent is added; After introducing synthesis gas into the reactor to replace the air, the pressure in the reactor is increased to a predetermined pressure with the synthesis gas, and stirring is started at the same time. Then, the temperature in the reactor is increased to a predetermined temperature and maintained for a predetermined time to obtain methanol.

10. The method for preparing methanol from synthesis gas according to claim 9, characterized in that: The catalyst mass is 0.5-5 g; the solvent volume is 10-50 mL; the solvent is butanol; the reaction pressure is 2-5 MPa; the predetermined temperature is 150-190° C.; the predetermined time is 20 h; and the stirring speed is 2000 rpm.

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