Catalyst for hydrogenation of co / co2 to methanol and preparation method and application thereof

Abstract

The application provides a catalyst for preparing methanol by CO / CO2 hydrogenation and a preparation method thereof. The preparation method takes copper salt, iron salt, functional ligand and auxiliary metal salt as raw materials, adopts a hydrothermal method and a coprecipitation method to obtain a catalyst precursor, and then the catalyst is obtained after drying and calcining the catalyst precursor. In the method, on one hand, the functional ligand forms a unique cyclopentadienone diphosphine framework, and on the other hand, metal auxiliaries are introduced. Both of the two aspects effectively improve the problem that Cu components in the existing Cu-based catalyst are prone to agglomeration and sintering, thereby prolonging the service life of the catalyst.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of catalysts, more particularly, to a catalyst for CO / CO2 hydrogenation to methanol and a preparation method and application thereof. BACKGROUND

[0002] Methanol is a liquid fuel very suitable for hydrogen production and is one of the clean green energy sources. The technology for preparing methanol from carbon dioxide has attracted much attention, and the core of the technology lies in the catalyst.

[0003] The noble metal catalyst has the advantages of high activity and good stability, but the cost of the catalyst is high, and it is difficult to realize large-scale industrial application. The Cu-based catalyst is currently most widely used in industry, and has the advantages of high cost performance, high activity, mild use conditions, good selectivity and less by-products, but the defect of the Cu-based catalyst lies in easy thermal sintering deactivation.

[0004] In order to continuously optimize the performance of copper-based catalysts, researchers have made various attempts. Patent CN202410329997.9 provides a method for introducing trivalent variable valence element X (X = Ti, Ce) and divalent variable valence Y (Cr, Fe) element to adjust the oxygen vacancy of CuZnZrOx catalyst, which improves the activity of the catalytic reaction, but the selectivity of methanol is low. Patent CN201110286798.7 prepared a CuO-Fe2O3 / SiO2 bimetallic catalyst by impregnation method, and the prepared catalyst has the advantages of high carbon monoxide conversion rate and good methanol selectivity, but the CuFe-based catalyst still has problems such as easy agglomeration and sintering of Cu component, and gradual increase in selectivity of by-products during the reaction process due to phase separation of Cu and Fe active components.

[0005] Therefore, there is an urgent need for a carbon oxide (CO / CO2) hydrogenation to methanol catalyst with mild reaction conditions, low cost, and high catalytic activity, selectivity and stability. SUMMARY

[0006] In view of the above technical problems existing in the prior art, the present application provides a CO / CO2 catalytic hydrogenation to methanol catalyst, which forms a unique cyclopentadienone diphosphine framework, which forms a confinement effect on the active component during carbonization, effectively improving the problem of easy agglomeration and sintering of Cu component in the existing Cu Fe-based catalyst, thereby prolonging the service life of the catalyst.

[0007] The basic idea of the technical solution adopted by the present application is as follows:

[0008] A preparation method of a CO / CO2 hydrogenation to methanol catalyst, comprising:

[0009] 1) Iron salt and cyclopentadienone are mixed uniformly in a solvent and then transferred to a reaction kettle for hydrothermal reaction;

[0010] 2) After the hydrothermal reaction is completed, solid powder is obtained by centrifugal separation, unreacted raw materials are removed by washing, and Fe-cyclopentadienone complex powder is obtained by vacuum drying;

[0011] 3) The salt solution of the auxiliary metal, the copper salt solution, the Fe-cyclopentadienone complex powder, and the precipitant solution are added to a reaction container, and the pH value is kept at 7.0 by water bath stirring to obtain a mixed solution;

[0012] 4) After the mixed solution is aged, a catalyst precursor is obtained by filtration and is calcined under a nitrogen atmosphere to obtain the carbon oxide hydrogenation methanol catalyst;

[0013] The auxiliary metal is one or more of Mg, Al, Zr, and Cr.

[0014] As one mode, the solvent in step (1) is N,N-dimethylformamide; wherein the molar ratio of iron salt to cyclopentadienone is 3:5.

[0015] Preferably, in step (3), the molar ratio of the copper salt solution to the salt solution of the auxiliary metal to the Fe-cyclopentadienone complex powder is 4:1:2.

[0016] Preferably, the iron salt is a ferric sulfate salt, a ferric nitrate salt, or a ferric chloride salt.

[0017] As one mode, in step 1), the temperature of the hydrothermal reaction is 110-150°C, and the reaction time is 18-26h.

[0018] As one mode, in step 2), N,N-dimethylformamide and ethanol are used for washing 3-4 times.

[0019] Preferably, the temperature of vacuum drying is 80-110°C, and the drying time is 4-8h.

[0020] As one mode, the specific operation mode of step (3) is: the salt solution of the auxiliary metal is added to the copper salt solution and mixed uniformly, and then the Fe-cyclopentadienone complex powder is added, and the mixed solution is obtained after stirring uniformly; the mixed solution and the precipitant solution are added to a three-necked flask using a peristaltic pump, and the pH value is kept at 7.0 by water bath stirring to obtain a mixed solution;

[0021] Alternatively, the specific operation mode of step (3) is as follows: the Fe-cyclopentadienyl ketone complex powder is added into the copper salt solution to obtain a mixed solution; the mixed solution and part of the precipitant solution are added into a three-necked flask by using a peristaltic pump; then the salt solution of the auxiliary metal and the remaining precipitant solution are continuously added into the three-necked flask by using the peristaltic pump, and water bath stirring is carried out to keep the pH value at 7.0, thereby obtaining a mixed solution.

[0022] Preferably, the concentrations of the salt solution of the auxiliary metal, the copper salt solution and the precipitant solution are respectively 0.2-0.5 mol / L; preferably, the precipitant is a carbonate.

[0023] As a mode, in step 4), the aging temperature is 70-90℃, the aging time is 1-2h; the calcination temperature is 300-400℃, the heating rate is 5-10℃ / min, and the calcination time is 3-5h.

[0024] The application further provides a CO / CO2 hydrogenation methanol catalyst prepared by the preparation method according to any one of the above.

[0025] The application further provides the application of the CO / CO2 hydrogenation methanol catalyst as described above, i.e. the catalyst is used to catalyze the hydrogenation of one or both of carbon monoxide and carbon dioxide to prepare methanol.

[0026] As a mode, the catalyst is subjected to an activation treatment before use, and the activation treatment is carried out under the following conditions: the activation atmosphere is hydrogen or a mixed gas of hydrogen and a non-active gas, the pressure is 0.1-1.0 MPa, the activation treatment temperature is 170-270℃, and the activation treatment time is 2-24h.

[0027] Preferably, the concentration of hydrogen in the mixed gas is 5.00%-99.99%; preferably, the non-active gas is at least one selected from helium, argon and nitrogen; preferably, the reaction pressure is 0.5-0.8 MPa; and the activation reaction temperature is 200-240℃.

[0028] As a mode, the mixed gas CO / CO2 / Ar and H2 are introduced to carry out the catalytic reaction, the target product of the reaction is methanol, the reaction temperature is 230-310℃, the reaction pressure is 4-8 MPa, and the reaction volume space velocity is 8000-10000h -1 ;

[0029] In the mixed gas CO / CO2 / Ar, the volume fraction of CO is 30%-40%, the volume fraction of CO2 is 5%-15%, and the volume fraction of Ar is 50%-60%; and the volume ratio of H2 to the mixed gas is 6:4.

[0030] The application has the following beneficial effects:

[0031] 1. The present application provides a catalyst for CO / CO2 hydrogenation to methanol, which is prepared by hydrothermal method and coprecipitation method. The preparation process conditions are simple, the raw materials are easy to obtain, and the price is low, which is conducive to large-scale production. At the same time, by adjusting the metal ratio of the precursor to optimize the content of the catalyst component, it is helpful to the synergistic effect of bimetallic, and the formation and stability of active phase.

[0032] 2. The catalyst of the present application can form a unique cyclopentadienone diphosphine framework by adding cyclopentadienone (CPD), which effectively improves the problem of easy agglomeration and sintering of Cu component in the existing Cu Fe-based catalyst, thereby significantly prolonging the service life of the catalyst.

[0033] 3. The catalyst of the present application has a carbon monoxide conversion rate of greater than 45% at 250℃, and a heat resistance retention rate of greater than 75%. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the technical scheme of the embodiments of the present application is described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present application, not all. Based on the described embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the present application.

[0035] Hereinafter, DMF is N,N-dimethylformamide, and CPD is cyclopentadienone.

[0036] Comparative Example 1

[0037] (1) 14.6g of Fe(NO3)3·9H2O and 5mL of cyclopentadienone (CPD) were added to DMF (40ML), and ultrasonic treatment was used until the mixture was uniform, the obtained mixed solution A was transferred to a reaction kettle, and then hydrothermal reaction was carried out in an oven at 120℃ for 24 hours.

[0038] (2) After the hydrothermal reaction was completed, the solid powder was separated by centrifugation, and washed with DMF and ethanol three times to remove the unreacted raw materials. Then the obtained sample was dried in a vacuum drying oven at 80℃ for 4 hours to obtain Fe-cyclopentadienone complex powder (Fe-CPD powder).

[0039] (3) 0.3 mol / L Na2CO3 aqueous solution 200 ml, 0.3 mol / L Cu(NO3)2 aqueous solution 100 ml; 1 g Fe-CPD powder was put into the Cu(NO3)2 aqueous solution, stirred at 60℃ for 1 h, and then mixed solution B was obtained; mixed solution B and Na2CO3 aqueous solution were added into a three-necked flask at the same time by using a peristaltic pump, and stirred in a 70℃ water bath, keeping the pH value at 7.0, and then mixed solution C was obtained.

[0040] (4) After mixed solution C was aged at 80℃ for 2 h, the catalyst precursor was obtained by filtration, and then the precursor was heated at 110℃ (the heating rate was 5℃ / min) in a tube furnace under argon atmosphere for 5 h, and then the precursor was calcined at 350℃ under nitrogen atmosphere at a heating rate of 5℃ / min for 3 h, and then Cu / Fe-CPD catalyst was obtained. -1 ) under argon atmosphere for 5 h, and then the precursor was calcined at 350℃ under nitrogen atmosphere at a heating rate of 5℃ / min for 3 h, and then Cu / Fe-CPD catalyst was obtained. -1 ) under argon atmosphere for 5 h, and then the precursor was calcined at 350℃ under nitrogen atmosphere at a heating rate of 5℃ / min for 3 h, and then Cu / Fe-CPD catalyst was obtained.

[0041] Comparative Example 2

[0042] 0.3 mol / L Na2CO3 aqueous solution 220 ml, 0.3 mol / L Fe(NO3)3·9H2O solution 50 ml and 0.3 mol / L Cu(NO3)2 aqueous solution 100 ml were measured, and Fe(NO3)3·9H2O solution, Cu(NO3)2 aqueous solution and Na2CO3 aqueous solution were added into a three-necked flask at the same time by using a peristaltic pump, and stirred in a 70℃ water bath, keeping the pH value at 7.0.

[0043] After the obtained mixed solution was aged at 80℃ for 2 h, the catalyst precursor was obtained by filtration, and then the precursor was heated at 110℃ (the heating rate was 5℃ / min) in a tube furnace under argon atmosphere for 5 h, and then the precursor was calcined at 350℃ under nitrogen atmosphere at a heating rate of 5℃ / min for 3 h, and then Cu / Fe catalyst was obtained. -1 ) under argon atmosphere for 5 h, and then the precursor was calcined at 350℃ under nitrogen atmosphere at a heating rate of 5℃ / min for 3 h, and then Cu / Fe-CPD catalyst was obtained. -1 ) under argon atmosphere for 5 h, and then the precursor was calcined at 350℃ under nitrogen atmosphere at a heating rate of 5℃ / min for 3 h, and then Cu / Fe-CPD catalyst was obtained.

[0044] Example 1

[0045] (1) 14.6 g of Fe(NO3)3·9H2O and 5 mL of cyclopentadienone (CPD) were added to DMF (40 ML), and the mixture was uniformly treated by ultrasonic treatment, and then the obtained mixed solution A was transferred into a reaction kettle, and then hydrothermal reaction was carried out in an oven at 120℃ for 24 hours.

[0046] (2) After the completion of the hydrothermal reaction, the solid powder was separated by centrifugation, and washed with DMF and ethanol three times to remove the unreacted raw materials. Finally, the obtained sample was dried in a vacuum drying oven at 80℃ for 4 hours to obtain Fe-cyclopentadienone complex powder.

[0047] (3) Measure 50 ml of 0.2 mol / L Na2CO3 aqueous solution, 20 ml of 0.2 mol / L Cu(NO3)2 aqueous solution and 5 ml of 0.2 mol / L Mg(NO3)2 solution. Add the Mg(NO3)2 solution to the Cu(NO3)2 solution and mix well. Add 1 g of Fe-CPD powder to the mixture and stir at 60°C for 1 h to obtain mixed solution B. Use a peristaltic pump to add mixed solution B and Na2CO3 aqueous solution dropwise to a three-necked flask. Stir in a water bath at 70°C and keep the pH value at 7.0 to obtain mixed solution C.

[0048] (4) The resulting mixture C was aged at 80℃ for 2 hours and then filtered to obtain the catalyst precursor; it was then heated at 110℃ (heating rate of 5℃ / min). -1 The precursor was heated in an argon atmosphere tube furnace for 5 hours, and then heated in a nitrogen atmosphere at 5°C for 1 minute. -1 The T-Cu / Fe-CPD-Mg catalyst was obtained by calcining at 350℃ for 3 hours.

[0049] Example 2

[0050] (1) Add 14.6g of Fe(NO3)3·9H2O and 5mL of cyclopentadienone (CPD) to DMF (40mL), and use sonication to mix until homogeneous. Transfer the resulting mixed solution A to a reaction vessel and then carry out a hydrothermal reaction at 120°C in an oven for 24 hours.

[0051] (2) After the hydrothermal reaction was completed, the solid powder was obtained by centrifugation and washed three times with DMF and ethanol to remove unreacted raw materials. Finally, the obtained sample was dried in a vacuum drying oven at 80°C for 4 hours to obtain the Fe-cyclopentadienone complex.

[0052] (3) Measure 40 ml of 0.2 mol / L Na2CO3 aqueous solution and 20 ml of 0.2 mol / L Cu(NO3)2 solution. Put 1 g of Fe-CPD powder into copper nitrate aqueous solution and stir at 60℃ for 1 h to obtain mixture B. Use a peristaltic pump to add mixture B and Na2CO3 aqueous solution dropwise into a three-necked flask. Then measure 5 ml of 0.2 mol / L Mg(NO3)2 solution and 10 ml of 0.2 mol / L Na2CO3 aqueous solution and add them dropwise into the above three-necked flask using a peristaltic pump. Stir in a water bath at 70℃ and keep the pH value at 7.0 to obtain mixture C.

[0053] (4) After aging the obtained mixture C at 80℃ for 2 hours, the catalyst precursor was obtained by filtration and then heated at 110℃ (heating rate of 5℃ / min). -1 The precursor was heated in an argon atmosphere tube furnace for 5 hours, and then heated in a nitrogen atmosphere at 5°C for 1 minute.-1 The obtained mixture solution B and the Na2CO3 aqueous solution were simultaneously added into a three-necked flask by using a peristaltic pump, and stirred in a 70°C water bath to keep the pH value at 7.0, to obtain a mixed solution C.

[0054] Example 3

[0055] (1) 14.6 g of Fe(NO3)3·9H2O and 5 mL of cyclopentadienone (CPD) were added into DMF (40 mL) and mixed uniformly by using ultrasonic treatment, and the obtained mixture solution A was transferred into a reaction kettle, and then aged in an oven at 120°C for 24 hours.

[0056] (2) After the hydrothermal reaction was completed, the solid powder was separated by centrifugation, and washed with DMF and ethanol for three times to remove the unreacted raw materials. Finally, the obtained sample was dried in a vacuum drying oven at 80°C for 4 hours to obtain a Fe-cyclopentadienone complex.

[0057] (3) 50 ml of a 0.2 mol / L Na2CO3 aqueous solution, 20 ml of a 0.2 mol / L Cu(NO3)2 aqueous solution and 5 ml of a 0.2 mol / L Al(NO3)3 solution were measured, the Al(NO3)3 solution was added into the Cu(NO3)2 aqueous solution and mixed uniformly, then 1 g of Fe-CPD powder was added, and after stirring at 60°C for 1 hour, a mixed solution B was obtained; the obtained mixed solution B and the Na2CO3 aqueous solution were simultaneously added into a three-necked flask by using a peristaltic pump, and stirred in a 70°C water bath to keep the pH value at 7.0, to obtain a mixed solution C.

[0058] (4) After the obtained mixed solution C was aged at 80°C for 2 hours, a catalyst precursor was obtained by filtration, and then the precursor was heated in a tube furnace under an argon atmosphere at a temperature increasing rate of 5°C / min -1 ) to 110°C for 5 hours, and then calcined at 350°C for 3 hours at a temperature increasing rate of 5°C / min -1 under a nitrogen atmosphere to obtain a T-Cu / Fe-CPD-Al catalyst.

[0059] Example 4

[0060] (1) 14.6 g of Fe(NO3)3·9H2O and 5 mL of cyclopentadienone (CPD) were added into DMF (40 mL) and mixed uniformly by using ultrasonic treatment, and the obtained mixture solution A was transferred into a reaction kettle, and then aged in an oven at 120°C for 24 hours.

[0061] (2) After the hydrothermal reaction was completed, the solid powder was separated by centrifugation, and washed with DMF and ethanol for three times to remove the unreacted raw materials. Finally, the obtained sample was dried in a vacuum drying oven at 80°C for 4 hours to obtain a Fe-cyclopentadienone complex.

[0062] (3) Measured 40 ml of 0.2 mol / L Na2CO3 aqueous solution, 20 ml of 0.2 mol / L Cu(NO3)2 aqueous solution, and 1 g of Fe-CPD powder was added into the copper nitrate aqueous solution, stirred at 60°C for 1 h, and then mixed solution B was obtained; using a peristaltic pump, mixed solution B and the Na2CO3 aqueous solution were simultaneously added into a three-necked flask; then, 5 ml of 0.2 mol / L Al(NO3)3 aqueous solution and 10 ml of 0.2 mol / L Na2CO3 aqueous solution were measured and simultaneously added into the above three-necked flask using a peristaltic pump, and stirred at 70°C water bath, keeping the pH value at 7.0, and then mixed solution C was obtained.

[0063] (4) After the obtained mixed solution C was aged at 80°C for 2 h, the catalyst precursor was obtained by filtration, and then the catalyst precursor was heated at 110°C (the temperature increasing rate was 5°C / min) for 5 h in a tube furnace under an argon atmosphere, and then the precursor was calcined at 350°C for 3 h under a nitrogen atmosphere at a temperature increasing rate of 5°C / min, and then F-Cu / Fe-CPD-Al catalyst was obtained. -1 ) under a nitrogen atmosphere at a temperature increasing rate of 5°C / min, and then F-Cu / Fe-CPD-Al catalyst was obtained. -1

[0064] Example 5

[0065] (1) 14.6 g of Fe(NO3)3·9H2O and 5 mL of cyclopentadienone (CPD) were added into DMF (40 mL), and the obtained mixture A was transferred into a reaction kettle, and then the mixture was hydrothermally reacted at 120°C in an oven for 24 hours.

[0066] (2) After the hydrothermal reaction was completed, the solid powder was obtained by centrifugal separation, and then the solid powder was washed with DMF and ethanol for three times to remove the unreacted raw materials. Finally, the obtained sample was dried in a vacuum drying oven at 80°C for 4 hours, and then Fe-cyclopentadienone complex powder (Fe-CPD powder) was obtained.

[0067] (3) Measured 50 ml of 0.2 mol / L Na2CO3 aqueous solution, 20 ml of 0.2 mol / L Cu(NO3)2 aqueous solution, and 5 ml of 0.2 mol / L ZrCl4 solution, and then the ZrCl4 solution was added into the copper nitrate aqueous solution and mixed uniformly, and then 1 g of Fe-CPD powder was added, and then mixed solution B was obtained after stirring at 60°C for 1 h; using a peristaltic pump, mixed solution B and the Na2CO3 aqueous solution were simultaneously added into a three-necked flask, and then mixed solution C was obtained by stirring at 70°C water bath, keeping the pH value at 7.0.

[0068] (4) After the obtained mixed solution C was aged at 80°C for 2 h, the catalyst precursor was obtained by filtration, and then the catalyst precursor was heated at 110°C (the temperature increasing rate was 5°C / min) for 5 h in a tube furnace under an argon atmosphere, and then the precursor was calcined at 350°C for 3 h under a nitrogen atmosphere at a temperature increasing rate of 5°C / min, and then F-Cu / Fe-CPD-Al catalyst was obtained. -1 ​-1 -1 -1

[0069] Example 6

[0070] (1) 14.6 g of Fe(N03)3-9H20 and 5 mL of cyclopentadienone (CPD) were added to DMF (40 mL) and mixed uniformly using ultrasonic treatment. The obtained mixed solution A was transferred to a reaction kettle, and then a hydrothermal reaction was performed at 120°C in an oven for 24 hours.

[0071] (2) After the hydrothermal reaction was completed, the solid powder was separated by centrifugation and washed with DMF and ethanol three times to remove unreacted raw materials. Finally, the obtained sample was dried in a vacuum drying oven at 80°C for 4 hours to obtain Fe-cyclopentadienone complex powder (Fe-CPD powder).

[0072] (3) 40 mL of 0.2 mol / L Na2C03 aqueous solution and 20 mL of 0.2 mol / L Cu(N03)2 aqueous solution were measured, and 1 g of Fe-CPD powder was placed in the copper nitrate aqueous solution. After stirring at 60°C for 1 hour, mixed solution B was obtained. Mixed solution B and the Na2C03 aqueous solution were simultaneously added to a three-necked flask using a peristaltic pump. Then, 5 mL of 0.2 mol / L ZrCl4 solution and 10 mL of 0.2 mol / L Na2C03 aqueous solution were measured and simultaneously added to the above three-necked flask using a peristaltic pump. The pH value was maintained at 7.0 by stirring in a 70°C water bath to obtain mixed solution C.

[0073] (4) After the obtained mixed solution C was aged at 80°C for 2 hours, the catalyst precursor was obtained by filtration. The precursor was heated in an argon atmosphere tube furnace at 110°C (the temperature was raised at a rate of 5°C / min -1 ) for 5 hours, and then the precursor was calcined at 350°C under a nitrogen atmosphere at a temperature rising rate of 5°C / min -1 for 3 hours to obtain F-Cu / Fe-CPD-Zr catalyst.

[0074] Example 7

[0075] (1) 14.6 g of Fe(N03)3-9H20 and 5 mL of cyclopentadienone (CPD) were added to DMF (40 mL) and mixed uniformly using ultrasonic treatment. The obtained mixed solution A was transferred to a reaction kettle, and then a hydrothermal reaction was performed at 120°C in an oven for 24 hours.

[0076] (2) After the hydrothermal reaction was completed, the solid powder was obtained by centrifugation and washed three times with DMF and ethanol to remove unreacted raw materials. Finally, the obtained sample was dried in a vacuum drying oven at 80°C for 4 hours to obtain Fe-cyclopentadienone complex powder (Fe-CPD powder).

[0077] (3) Measure 50 ml of 0.2 mol / L Na2CO3 aqueous solution, 20 ml of 0.2 mol / L Cu(NO3)2 solution and 5 ml of 0.2 mol / L Cr(NO3)3·9H2O solution. Mix the Cu(NO3)2 solution and Cr(NO3)3·9H2O solution and then add 1 g of Fe-CPD powder. Stir at 60℃ for 1 h to obtain mixed solution B. Use a peristaltic pump to simultaneously add mixed solution B and Na2CO3 aqueous solution to a three-necked flask. Stir in a water bath at 70℃ and keep the pH value at 7.0 to obtain mixed solution C.

[0078] (4) After aging the obtained mixture C at 80℃ for 2 hours, the catalyst precursor was obtained by filtration and then heated at 110℃ (heating rate of 5℃ / min). -1 The precursor was heated in an argon atmosphere tube furnace for 5 hours, and then heated in a nitrogen atmosphere at 5°C for 1 minute. -1 The T-Cu / Fe-CPD-Cr catalyst was obtained by calcining at 350℃ for 3 hours.

[0079] Example 8

[0080] (1) Add 14.6g of Fe(NO3)3·9H2O and 5mL of cyclopentadienone (CPD) to DMF (40mL), and use sonication to mix until homogeneous. Transfer the obtained mixed solution A to a reaction vessel and then carry out a hydrothermal reaction at 120℃ in an oven for 24 hours.

[0081] (2) After the hydrothermal reaction was completed, the solid powder was obtained by centrifugation and washed three times with DMF and ethanol to remove unreacted raw materials. The obtained sample was then dried in a vacuum drying oven at 80°C for 4 hours to obtain Fe-cyclopentadienone complex powder (Fe-CPD powder).

[0082] (3) Measuring 40 ml of 0.2 mol / L Na2CO3 aqueous solution, 20 ml of 0.2 mol / L Cu(NO3)2 aqueous solution, and putting 1 g of Fe-CPD powder into the copper nitrate aqueous solution, stirring at 60°C for 1 h to obtain a mixed solution B; using a peristaltic pump, the mixed solution B and the Na2CO3 aqueous solution are simultaneously dropped into a three-necked flask; then, measuring 5 ml of 0.2 mol / L Cr(NO3)3·9H2O aqueous solution and 10 ml of 0.2 mol / L Na2CO3 aqueous solution, and using a peristaltic pump, the two solutions are simultaneously dropped into the above three-necked flask, stirring at 70°C water bath, keeping the pH value at 7.0, to obtain a mixed solution C.

[0083] (4) After the obtained mixed solution C is aged at 80°C for 2 h, a catalyst precursor is obtained by filtration, and then the precursor is heated at 110°C (the temperature increasing rate is 5°C / min) for 5 h in a tube furnace under an argon atmosphere, and then the precursor is calcined at 350°C for 3 h under a nitrogen atmosphere with a temperature increasing rate of 5°C / min, to obtain a F-Cu / Fe-CPD-Cr catalyst. -1 ) under a nitrogen atmosphere with a temperature increasing rate of 5°C / min, to obtain a F-Cu / Fe-CPD-Cr catalyst. -1

[0084] Performance test

[0085] The catalysts obtained in Examples 1-8 and Comparative Examples 1-2 are subjected to a catalyst performance test in a fixed bed reactor.

[0086] Measuring 1 ml of the catalyst obtained in Examples 1-8 and Comparative Examples 1-2 with a mesh size of 20-40 and 1 mL of quartz sand with the same mesh size, uniformly mixing, and then loading into the isothermal zone of the fixed bed reactor. The catalytic reaction conditions are a temperature of 250°C, a reaction pressure of 5 MPa, a reaction volume space velocity of 10000 h-1, and a mixed reaction gas CO / CO2 / Ar / H2 volume ratio of 14% / 4% / 22% / 60%, wherein Ar is an internal standard gas for gas chromatography analysis. The carbon dioxide, carbon monoxide and methane in the gas phase products are quantitatively analyzed by an online gas chromatograph equipped with a TCD detector, and the compounds in the liquid phase products are quantitatively analyzed by an online gas chromatograph equipped with a TCD detector, and finally the carbon monoxide conversion rate and the methanol content in the liquid phase are calculated.

[0087] The catalyst evaluation process is as follows: the catalyst is tested for initial activity under the reaction condition of 250°C, after a period of reaction, the temperature is increased to 380°C for high-temperature treatment to accelerate the deactivation of the catalyst, after a period of heat resistance, the reaction temperature is decreased back to 250°C, the heat resistance activity after heat resistance is tested, and the percentage of the heat resistance activity after heat resistance to the initial activity is the heat resistance retention rate, which is usually used to replace the life experiment.

[0088] The CO / CO2 hydrogenation performance test results are shown in Table 1.

[0089] ​Table 1 CO / CO2 hydrogenation performance over different catalysts

[0090]

[0091] Although the embodiments of the present application have been disclosed with reference to the above embodiments, the above description is merely used to facilitate understanding of the present application and is not used to limit the present application. Any modification and change in the form and details of the embodiments can be made by any person skilled in the art without departing from the spirit and scope of the present application, and the patent protection scope of the present application should be subject to the scope defined by the claims.

Claims

1. A method for preparing a catalyst for the hydrogenation of CO / CO2 to methanol, characterized in that, include: 1) Add the iron salt and cyclopentadienone to the solvent and mix, then transfer to a reaction vessel for hydrothermal reaction; 2) After the hydrothermal reaction is complete, the solid powder is obtained by centrifugation, unreacted raw materials are washed away, and the powder is dried under vacuum to obtain Fe-cyclopentadienone complex powder. 3) Add the salt solution of the auxiliary metal, the copper salt solution, the Fe-cyclopentadienone complex powder, and the precipitant solution dropwise into the reaction vessel, stir in a water bath and maintain the pH value at 7.0 to obtain a mixed solution; 4) After aging, the mixture is filtered to obtain the catalyst precursor and calcined under a nitrogen atmosphere to obtain the catalyst for the hydrogenation of CO / CO2 to methanol. The auxiliary metal is one or more of Mg, Al, Zr, and Cr; The solvent in step 1) is N,N-dimethylformamide; wherein the molar ratio of iron salt to cyclopentadienone is 3:5; In step 3), the molar ratio of copper salt solution: salt solution of auxiliary metal: Fe-cyclopentadienone complex powder is 4:1:2; Iron salts are ferric sulfate, ferric nitrate, or ferric chloride.

2. The method for preparing the catalyst for CO / CO2 hydrogenation to methanol according to claim 1, characterized in that, In step 1), the hydrothermal reaction temperature is 110~150℃ and the reaction time is 18~26h.

3. The method for preparing the catalyst for CO / CO2 hydrogenation to methanol according to claim 1, characterized in that, In step 2), the product is washed 3-4 times with N,N-dimethylformamide and ethanol; the vacuum drying temperature is 80-110℃ and the drying time is 4-8h.

4. The method for preparing the catalyst for CO / CO2 hydrogenation to methanol according to claim 1, characterized in that, The specific operation method of step 3) is as follows: add the salt solution of the auxiliary metal and the Fe-cyclopentadienone complex powder to the copper salt solution and mix and stir evenly to obtain a mixed solution; use a peristaltic pump to drop the mixed solution and the precipitant solution into the reaction vessel, stir in a water bath and maintain the pH value at 7.0 to obtain the mixed liquid; Alternatively, step 3) can be performed as follows: Fe-cyclopentadienone complex powder is added to a copper salt solution and mixed to obtain a mixed solution; the mixed solution and a portion of the precipitant solution are added to a three-necked flask using a peristaltic pump; then the salt solution of the auxiliary metal and the remaining precipitant solution are added to the three-necked flask using a peristaltic pump, the mixture is stirred in a water bath and the pH is maintained at 7.0 to obtain the mixed solution. The concentrations of the auxiliary metal salt solution, copper salt solution, and precipitant solution are 0.2~0.5 mol / L, respectively; the precipitant is a carbonate.

5. The method for preparing the catalyst for CO / CO2 hydrogenation to methanol according to claim 1, characterized in that, In step 4), the aging temperature is 70~90℃ and the aging time is 1~2h; the calcination temperature is 300~400℃, the heating rate is 5~10℃ / min, and the calcination time is 3~5h.

6. A catalyst for the hydrogenation of CO / CO2 to methanol, characterized in that, The preparation method according to any one of claims 1-5 is obtained.

7. The application of the catalyst for CO / CO2 hydrogenation to methanol as described in claim 6, characterized in that, The catalyst is used to catalyze the hydrogenation of one or a combination of CO or CO2 gases to produce methanol.

8. The application according to claim 7, characterized in that, The catalyst is activated before use. The activation treatment is performed in the following manner: the activation atmosphere is hydrogen or a mixture of hydrogen and inactive gas, the pressure is 0.1 to 1.0 MPa, the activation temperature is 170 to 270°C, and the activation time is 2 to 24 hours.

9. The application according to claim 8, characterized in that, The hydrogen concentration in the mixed gas is 5.00% to 99.99%; the inactive gas is selected from at least one of helium, argon, and nitrogen; the activation treatment pressure is 0.5 to 0.8 MPa; and the activation treatment temperature is 200 to 240°C.

10. The application according to claim 7, characterized in that, A catalytic reaction is carried out by introducing a mixture of CO / CO2 / Ar and H2, with methanol as the target product. The reaction temperature is 230-310℃, the reaction pressure is 4-8 MPa, and the reaction volume hourly space velocity is 8000-10000 h⁻¹. -1 ; In the CO / CO2 / Ar mixture, the volume fraction of CO is 30%~40%, the volume fraction of CO2 is 5%~15%, and the volume fraction of Ar is 50%~60%; the volume ratio of H2 to the mixture is 6:4.

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