Catalyst for preparing synthesis gas through hydrogenation of carbon dioxide and preparation method and application thereof

Abstract

The invention discloses a catalyst for preparing synthesis gas by hydrogenation of carbon dioxide and a preparation method and application thereof, the catalyst takes indium oxide rich in oxygen vacancies as a carrier, metal Ni is loaded on the surface or surface layer of the carrier, and the metal is highly dispersed by nitrogen-doped carbon to form a composite material. Reducing substances generated in the process that 1, 10-phenanthroline is roasted to form nitrogen-doped carbon can partially reduce indium oxide to enable the indium oxide to be rich in oxygen vacancies, and alkali metal is used as an electron donor, so that the catalyst has relatively good carbon dioxide adsorption performance, loaded Ni has relatively good hydrogen dissociation performance, the catalyst has very good CO2 hydrogenation performance, and the catalyst has good catalytic activity at 360 DEG C; the CO2 conversion rate can reach 31%, and the CO selectivity can reach 99%.

Description

Technical field:

[0001] The present invention relates to the technical field of preparing synthesis gas by hydrogenating carbon dioxide, and in particular to a catalyst for preparing synthesis gas by hydrogenating carbon dioxide, and a preparation method and application thereof. Background technology:

[0002] The conversion of carbon dioxide (CO2) into carbon monoxide (CO) has important significance and multi-faceted application value, including: 1. Chemical production: Carbon monoxide (CO) is an important intermediate in the synthesis of many chemicals. It can be used to produce chemicals such as methanol, dimethyl ether, and methane, and has a wide range of applications. 2. Fuel synthesis: Carbon monoxide (CO) can be reacted with hydrogen (H2) to produce low-carbon olefins, fuels, lubricants and other products through the Fischer-Tropsch synthesis reaction. 3. Energy storage: The conversion of carbon dioxide into carbon monoxide can use carbon dioxide as a form of storage for renewable energy, achieving efficient utilization and storage of energy. 4. Environmental protection: By converting carbon dioxide into useful chemicals and fuels, carbon dioxide emissions can be reduced, which helps to mitigate climate change and reduce the impact of carbon emissions on the environment. Therefore, the conversion of carbon dioxide into carbon monoxide is an important way to utilize CO2.

[0003] Traditional catalysts have some problems in the process of converting carbon dioxide (CO2) to carbon monoxide (CO), including: 1. Low selectivity: Some traditional catalysts produce byproducts during the reaction, which reduces the selectivity of CO and affects the purity and yield of the product. 2. Poor stability: Some catalysts are easily deactivated or lose activity under high temperature and high pressure reaction conditions, resulting in a short catalyst life and the need for frequent replacement or regeneration. 3. Harsh operating conditions: Some catalysts require higher operating temperatures and pressures to achieve higher conversion rates, increasing energy consumption and production costs. 4. Complex synthesis: The synthesis process of some catalysts is complex, requiring expensive precursor materials and multi-step reactions, making it difficult to mass produce and industrialize. 5. Poor environmental friendliness: Some traditional catalysts may contain precious metals or other components that are harmful to the environment, which is not conducive to sustainable development and environmental protection requirements. Therefore, previous catalysts have problems in selectivity, stability, operating conditions, synthesis complexity, and environmental friendliness, which limit the efficiency and sustainability of carbon dioxide to carbon monoxide conversion. Summary of the invention:

[0004] The purpose of the present invention is to provide a catalyst for preparing synthesis gas by hydrogenating carbon dioxide, and a preparation method and application thereof.

[0005] The present invention is achieved through the following technical solutions:

[0006] A carbon dioxide hydrogenation synthesis gas catalyst is composed of indium oxide, nitrogen-doped carbon and nickel. Indium oxide rich in oxygen vacancies is used as a carrier and nickel is loaded. The nickel loading amount is 0.5wt% to 20wt%, and 10wt% is most preferred.

[0007] The nickel is highly dispersed with nitrogen-doped carbon to form a composite material.

[0008] In particular, an alkali metal or its oxide is also supported. Preferably, the molar ratio of the alkali metal or its oxide to nickel is 1-10:10, and most preferably 1:5.

[0009] Indium oxide rich in oxygen vacancies is used as a carrier. Indium oxide has a high ability to catalyze CO2 hydrogenation reactions. On this basis, nickel dispersed by nitrogen-doped carbon is loaded to enhance the ability to crack hydrogen. Alkaline metals can also be added to enhance the adsorption capacity of carbon dioxide. The catalyst has the ability to efficiently catalyze CO2 hydrogenation to produce CO at a relatively low temperature, maintains high stability, has a simple preparation method, and does not use precious metals.

[0010] The preparation method of the catalyst is as follows: dissolving a stoichiometric nickel metal precursor and a nitrogen-containing organic matter in anhydrous ethanol, then adding indium oxide or indium hydroxide powder, heating and stirring for several hours and then drying the solid, introducing an inert gas in a tubular furnace or first introducing air and then converting it into an inert gas, air when below 250° C. and inert gas when above 250° C., calcining the catalyst precursor at 250-500° C. to obtain the catalyst.

[0011] The molar ratio of the nickel metal precursor to the nitrogen-containing organic matter is 1:1-3.

[0012] Specifically, the calcination temperature was raised from room temperature to 250° C., maintained for 1 hour, and then raised to 500° C., maintained for 3 hours.

[0013] The inert gas is nitrogen or argon. If only nitrogen or argon is introduced into the tube furnace, the effect is slightly worse. It is better to introduce air first and then nitrogen or argon.

[0014] In particular, the catalyst also carries an alkali metal or its oxide, and when the nickel metal precursor is nickel acetate and the nitrogen-containing organic matter is 1,10-phenanthroline, the method specifically comprises the following steps: pouring an alkali metal salt, nickel acetate and 1,10-phenanthroline into anhydrous ethanol according to a certain molar ratio, magnetically stirring at room temperature for 30 minutes, adding indium hydroxide or indium oxide, vigorously stirring at 80° C. for 3 hours, pouring the generated suspension into an evaporating dish, and drying at low pressure in a vacuum drying oven at 60° C.; grinding the dried solid and placing it in a tubular furnace for roasting, and continuously introducing gas.

[0015] The alkali metal salt is one or more of lithium acetate, lithium nitrate, cesium acetate, cesium nitrate, sodium acetate, sodium nitrate, potassium acetate, potassium nitrate, rubidium acetate, and rubidium nitrate;

[0016] The molar ratio of the alkali metal salt to the nickel acetate is 1-10:10, and the molar ratio of the total amount of metals composed of the alkali metal salt and the nickel acetate to 1,10-phenanthroline is 1:1-3.

[0017] The present invention also protects the application of the carbon dioxide hydrogenation synthesis gas catalyst in the carbon dioxide hydrogenation reaction, and the application conditions are: the catalyst is placed in the middle section of a stainless steel tubular furnace, the catalyst is fixed by quartz wool and a quartz rod, a reaction mixed gas is introduced, the mixed gas components are argon, carbon dioxide and hydrogen in a molar ratio of 1:6:18, the mixed gas flow rate is 30 to 100 sccm, heating and pressurization are applied to promote the reaction, the reaction temperature is 260 to 360°C, and the reaction pressure is 0.2 to 4MPa.

[0018] The beneficial effects of the present invention are:

[0019] The catalyst of the present invention uses indium oxide rich in oxygen vacancies as a carrier, and loads metal Ni on the surface or surface layer of the carrier. The metal is highly dispersed by nitrogen-doped carbon to form a composite material. Since the reducing substances generated by 1,10-phenanthroline during the calcination process to form nitrogen-doped carbon will partially reduce the indium oxide, making it rich in oxygen vacancies, and with the aid of alkali metals as electron donors, it has good carbon dioxide adsorption performance, and the loaded Ni has good hydrogen dissociation performance, so that the catalyst has good CO2 hydrogenation performance. At 360°C, the CO2 conversion rate can reach 31%, and the CO selectivity can reach 99%. Description of the drawings:

[0020] Figure 1 This is a diagram showing the catalytic reaction effects of the catalysts obtained in Examples 1-7 in Example 8.

[0021] Figure 2 It is an AC-TEM image of the catalyst obtained in Example 6 of the present invention.

[0022] Figure 3 This is an EDX image of the catalyst obtained in Example 6 of the present invention.

[0023] Figure 4 This is a life test chart of the catalyst obtained in Example 6 in Example 9. Specific implementation method:

[0024] The following is a further description of the present invention, rather than a limitation of the present invention.

[0025] Example 1: Preparation of 5Ni / IO-1,10(3:1)-250,1,air,500,3,Ar catalyst

[0026] (1) 10 g of indium hydroxide was placed in a quartz boat and calcined in a muffle furnace at 550° C. for 3 h to obtain indium oxide (IO).

[0027] (2) 1 g of nickel acetate and 2.1726 g of 1,10-phenanthroline were poured into 15 mL of anhydrous ethanol and magnetically stirred at room temperature for 30 min to form a deep red solution. 4.7171 g of indium oxide (IO) was then added and vigorously stirred in an oil bath at 80°C for 3 h. The suspension was then poured into a glass petri dish and placed in a vacuum drying oven at 60°C. The temperature was evacuated to -0.1 MPa using a rotary vane vacuum pump and maintained at 60°C for 2 h. The formed pink powder was ground to obtain 5Ni / IO-1,10 (3:1).

[0028] (3) 5Ni / IO-1,10(3:1) was placed in a quartz boat, then in a quartz tube, and air was introduced. The temperature was raised to 250°C at a rate of 10°C / min. After holding for 1 hour, the gas was switched to argon and the temperature was raised to 500°C at a rate of 10°C / min. The temperature was held for 3 hours. After cooling, the catalyst 5Ni / IO-1,10(3:1)-250,1,air,500,3,Ar was obtained.

[0029] Example 2: Preparation of 5Ni / IHO-1,10(1:1)-250,1,500,3,Ar catalyst

[0030] (1) 1 g of nickel acetate and 0.7242 g of 1,10-phenanthroline were poured into 15 mL of anhydrous ethanol and magnetically stirred at room temperature for 30 min to form a deep red solution. 5.6354 g of indium hydroxide was then added and vigorously stirred in an oil bath at 80°C for 3 h. The suspension was then poured into a glass petri dish and placed in a vacuum drying oven at 60°C. The temperature was evacuated to -0.1 MPa using a rotary vane vacuum pump and maintained at 60°C for 2 h. The formed pink powder was ground to obtain 5Ni / IHO-1,10 (1:1).

[0031] (2) 5Ni / IHO-1,10(1:1) was placed in a quartz boat, then in a quartz tube, argon was introduced, and the temperature was raised to 250°C at a rate of 10°C / min, maintained for 1 hour, and then raised to 500°C at a rate of 10°C / min, maintained for 3 hours. After cooling, the catalyst was taken out to obtain 5Ni / IHO-1,10(1:1)-250,1,air,500,3,Ar catalyst.

[0032] Example 3: Preparation of 5Na5Ni / IHO-1,10(1:1)-250,1,500,3,N2 catalyst

[0033] (1) 1 g of nickel acetate, 0.3415 g of sodium nitrate and 0.8690 g of 1,10-phenanthroline were poured into 15 mL of anhydrous ethanol and magnetically stirred at room temperature for 30 min to form a deep red solution. 5.6354 g of indium hydroxide was then added and vigorously stirred in an oil bath at 80°C for 3 h. The suspension was then poured into a glass petri dish and placed in a vacuum drying oven at 60°C. The temperature was evacuated to -0.1 MPa using a rotary vane vacuum pump and maintained at 60°C for 2 h. The green powder formed was ground to obtain 5Na5Ni / IHO-1,10 (1:1).

[0034] (2) 5Na5Ni / IHO-1,10 (1:1) was placed in a quartz boat, then placed in a quartz tube, nitrogen was introduced, and the temperature was raised to 250°C at a rate of 10°C / min, maintained for 1 hour, and then raised to 500°C at a rate of 10°C / min, maintained for 3 hours. After cooling, the catalyst 5Na5Ni / IHO-1,10 (1:1)-250,1,500,3,N2 was obtained.

[0035] Example 4: Preparation of 5Cs5Ni / IHO-1,10(1:1)-250,1,500,3,N2 catalyst

[0036] (1) 1 g of nickel acetate, 0.7714 g of cesium acetate and 0.8690 g of 1,10-phenanthroline were poured into 15 mL of anhydrous ethanol and magnetically stirred at room temperature for 30 min to form a deep red solution. 5.6354 g of indium hydroxide was then added and vigorously stirred in an oil bath at 80°C for 3 h. The suspension was then poured into a glass petri dish and placed in a vacuum drying oven at 60°C. The temperature was evacuated to -0.1 MPa using a rotary vane vacuum pump and maintained at 60°C for 2 h. The green powder formed was ground to obtain 5Cs5Ni / IHO-1,10 (1:1).

[0037] (2) 5Cs5Ni / IHO-1,10(1:1) was placed in a quartz boat, then placed in a quartz tube, nitrogen was introduced, and the temperature was raised to 250°C at a rate of 10°C / min, maintained for 1 hour, and then raised to 500°C at a rate of 10°C / min, maintained for 3 hours. After cooling, the 5Cs5Ni / IHO-1,10(1:1)-250,1,500,3,N2 catalyst was obtained.

[0038] Example 5: Preparation of 5Cs5Ni / IHO-1,10(1:1)-250,1,air,500,3,Ar catalyst

[0039] (1) 1 g of nickel acetate, 0.7714 g of cesium acetate and 0.8690 g of 1,10-phenanthroline were poured into 15 mL of anhydrous ethanol and magnetically stirred at room temperature for 30 min to form a deep red solution. 5.6354 g of indium hydroxide was then added and vigorously stirred in an oil bath at 80°C for 3 h. The suspension was then poured into a glass petri dish and placed in a vacuum drying oven at 60°C. The temperature was evacuated to -0.1 MPa using a rotary vane vacuum pump and maintained at 60°C for 2 h. The green powder formed was ground to obtain 5Cs5Ni / IHO-1,10 (1:1).

[0040] (2) 5Cs5Ni / IHO-1,10(1:1) was placed in a quartz boat, then in a quartz tube, and air was introduced. The temperature was raised to 250°C at a rate of 10°C / min. After holding for 1 hour, the gas was switched to argon and the temperature was raised to 500°C at a rate of 10°C / min. The temperature was held for 3 hours. After cooling, the catalyst 5Cs5Ni / IHO-1,10(1:1)-250,1,air,500,3,Ar was obtained.

[0041] Example 6: Preparation of 2Cs10Ni / IHO-1,10(1:1)-250,1,500,3,N2 catalyst

[0042] (1) 2 g of nickel acetate, 0.3086 g of cesium acetate and 1.7384 g of 1,10-phenanthroline were poured into 15 mL of anhydrous ethanol and magnetically stirred at room temperature for 30 min to form a deep red solution. 5.6354 g of indium hydroxide was then added and vigorously stirred in an oil bath at 80°C for 3 h. The suspension was then poured into a glass petri dish and placed in a vacuum drying oven at 60°C. The temperature was evacuated to -0.1 MPa using a rotary vane vacuum pump and maintained at 60°C for 2 h. The green powder formed was ground to obtain 2Cs10Ni / IHO-1,10 (1:1).

[0043] (2) 2Cs10Ni / IHO-1,10(1:1) was placed in a quartz boat, then placed in a quartz tube, nitrogen was introduced, and the temperature was raised to 250°C at a rate of 10°C / min, maintained for 1 hour, and then raised to 500°C at a rate of 10°C / min, maintained for 3 hours. After cooling, the catalyst was taken out to obtain 2Cs10Ni / IHO-1,10(1:1)-250,1,500,3,N2 catalyst.

[0044] Example 7: Preparation of 2Cs10Ni / IHO-1,10(1:1)-250,1,air,500,3,Ar catalyst

[0045] (1) 2 g of nickel acetate, 0.3086 g of cesium acetate and 1.7384 g of 1,10-phenanthroline were poured into 15 mL of anhydrous ethanol and magnetically stirred at room temperature for 30 min to form a deep red solution. 5.6354 g of indium hydroxide was then added and vigorously stirred in an oil bath at 80°C for 3 h. The suspension was then poured into a glass petri dish and placed in a vacuum drying oven at 60°C. The temperature was evacuated to -0.1 MPa using a rotary vane vacuum pump and maintained at 60°C for 2 h. The green powder formed was ground to obtain 2Cs10Ni / IHO-1,10 (1:1).

[0046] (2) 2Cs10Ni / IHO-1,10(1:1) was placed in a quartz boat, then placed in a quartz tube, air was introduced, and the temperature was raised to 250°C at a rate of 10°C / min. After holding for 1 hour, the gas was switched to argon, and the temperature was raised to 500°C at a rate of 10°C / min. After cooling, the catalyst 2Cs10Ni / IHO-1,10(1:1)-250,1,500,3,Ar was obtained.

[0047] Example 8: Application of Catalyst

[0048] 0.1 g of catalyst was placed in the middle section of a 316L stainless steel tube with a diameter of 10 mm. The catalyst was fixed by quartz wool and a quartz rod. An electric heating furnace was installed outside the tube. The reaction mixture (Ar:CO2:H2=1:6:18) was introduced into the tube. After blowing at a flow rate of 400 sccm for 2 minutes, the back pressure valve was increased to make the gas pressure in the tube reach 4 MPa, the flow rate was reduced to 30 sccm, and the electric heating furnace was controlled to increase it to 300°C at a rate of 10°C / min. At the same time, the product composition was detected online by gas chromatography, and samples were taken every 15 minutes.

[0049] The calculation formula is: CO2 conversion rate = (intake CO2 concentration - outlet CO2 concentration * intake Ar concentration / outlet Ar concentration) / inlet CO2 concentration

[0050] CO selectivity = outlet CO concentration / (outlet CO concentration + outlet CH4 concentration + outlet CH3OH concentration)

[0051] Figure 1 This is a catalyst performance diagram obtained by using the catalysts prepared in Example 1, Example 2, Example 3, Example 4, Example 5, Example 6 and Example 7 according to the application method of this example.

[0052] Example 9: Application of 2Cs10Ni / IHO-1,10(1r1)-250,1,500,3,N2

[0053] 0.1g of catalyst was placed in the middle of a 316L stainless steel tube with a diameter of 10mm. The catalyst was fixed by quartz wool and a quartz rod. An electric heating furnace was installed outside the tube. A reaction mixture (Ar:CO2:H2=1:6:18) was introduced into the tube. After purging for 2 minutes at a flow rate of 400sccm, the back pressure valve was adjusted to make the gas pressure in the tube reach 4MPa. The flow rate was reduced to 30sccm. The electric heating furnace was controlled to increase the temperature to 360°C at a rate of 10°C / min. At the same time, the product components were detected online by gas chromatography, and samples were taken every 15 minutes. The calculation formula was the same as in Example 8.

[0054] Figure 4 This is a catalyst stability test chart obtained by using the catalyst prepared in Example 6 according to the application method of this example.

[0055] The above are only preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be regarded as limiting the present invention, and the protection scope of the present invention should be based on the scope defined by the claims. For ordinary technicians in this technical field, several improvements and modifications can be made without departing from the spirit and scope of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A catalyst for preparing synthesis gas by hydrogenating carbon dioxide, characterized in that: The composite material is composed of indium oxide, nitrogen-doped carbon and nickel. Indium oxide rich in oxygen vacancies is used as a carrier to load nickel. The nickel loading amount is 0.5wt% to 20wt%. The nickel is highly dispersed in the nitrogen-doped carbon to form a composite material.

2. The catalyst according to claim 1, characterized in that An alkali metal or its oxide is also supported.

3. The catalyst according to claim 2, characterized in that The molar ratio of the alkali metal or its oxide to nickel is 1-10:

10.

4. The method for preparing the catalyst according to claim 1, characterized in that: The steps are as follows: dissolving a stoichiometric nickel metal precursor and a nitrogen-containing organic matter in anhydrous ethanol, then adding indium oxide or indium hydroxide powder, heating and stirring for several hours and then drying the solid, introducing an inert gas in a tubular furnace or introducing air first and then converting it to an inert gas to calcine the catalyst precursor at 250-500°C to obtain a catalyst.

5. The method for preparing the catalyst according to claim 4, characterized in that: The molar ratio of the nickel metal precursor to the nitrogen-containing organic matter is 1:1-3.

6. The method for preparing the catalyst according to claim 4, characterized in that: The calcination temperature was raised from room temperature to 250°C, maintained for 1 hour, and then raised to 500°C and maintained for 3 hours.

7. The method for preparing the catalyst according to claim 4, characterized in that: The air is first introduced and then converted into an inert gas: air is used when the temperature is below 250°C, and inert gas is used when the temperature is above 250°C; the inert gas is nitrogen or argon.

8. The method for preparing the catalyst according to claim 4, characterized in that: The catalyst is also loaded with alkali metal or its oxide. When the nickel metal precursor is nickel acetate and the nitrogen-containing organic matter is 1,10-phenanthroline, the catalyst specifically comprises the following steps: pouring alkali metal salt, nickel acetate and 1,10-phenanthroline into anhydrous ethanol according to a certain molar ratio, magnetically stirring at room temperature for 30 minutes, adding indium hydroxide or indium oxide, vigorously stirring at 80°C for 3 hours, pouring the generated suspension into an evaporating dish, and drying at low pressure in a vacuum drying oven at 60°C; grinding the dried solid, placing it in a tubular furnace for roasting, and continuously introducing gas.

9. The method for preparing the catalyst according to claim 8, characterized in that: The alkali metal salt is one or more of lithium acetate, lithium nitrate, cesium acetate, cesium nitrate, sodium acetate, sodium nitrate, potassium acetate, potassium nitrate, rubidium acetate, and rubidium nitrate; the molar ratio of the alkali metal salt to nickel acetate is 1 to 10:10, and the molar ratio of the total amount of metal composed of the alkali metal salt and nickel acetate to 1,10-phenanthroline is 1:1 to 3.

10. Use of the catalyst according to claim 1 in carbon dioxide hydrogenation reaction, characterized in that: The application conditions are as follows: the catalyst is placed in the middle section of a stainless steel tube furnace, the catalyst is fixed by quartz wool and a quartz rod, a reaction mixed gas is introduced, the mixed gas composition is argon, carbon dioxide and hydrogen in a molar ratio of 1:6:18, the mixed gas flow rate is 30 to 100 sccm, heating and pressurization are applied to promote the reaction, the reaction temperature is 260 to 360°C, and the reaction pressure is 0.2 to 4MPa.

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