A supported anti-perovskite nitride catalyst, a preparation method and application thereof

Abstract

The application provides a preparation method of a supported anti-perovskite nitride catalyst, comprising the following steps: S1) performing a thermal polymerization reaction on a carbon-nitrogen monomer in an air atmosphere to convert the carbon-nitrogen monomer into a carbon nitride material; S2) mixing and dispersing the carbon nitride material and a metal salt solution, and drying to obtain a calcined precursor; and S3) calcining the calcined precursor to obtain the supported anti-perovskite nitride catalyst. The application provides a universal method for preparing a supported anti-perovskite nitride catalyst, which uses a carbon nitride as a carbon source and a nitrogen source, and obtains a carbon-supported anti-perovskite nitride catalyst through impregnation and in-situ pyrolysis, and the catalyst has excellent catalytic activity and selectivity, can obtain a high space-time yield (more than 1 g CH3OH / g cat / h), and has good stability. The preparation process is simple, easy to operate, and easy to repeat, and has a good application prospect.

Description

Technical Field

[0001] This invention relates to the field of catalyst technology, and in particular to a supported anti-perovskite nitride catalyst, its preparation method, and its application. Background Technology

[0002] Methanol, as an important chemical raw material, can be used to manufacture high-value-added fuels and chemicals such as olefins, gasoline, biodiesel, and fuel additives. Currently, my country's annual methanol production capacity is approximately 93 million tons. At present, most methanol is still synthesized from fossil fuels via the catalytic conversion of syngas, a route that involves the generation and emission of large amounts of carbon dioxide. Therefore, utilizing the catalytic hydrogenation of carbon dioxide to produce methanol can not only reduce the consumption of traditional fossil fuels but also effectively alleviate the environmental problems caused by carbon emissions.

[0003] Catalyst design and synthesis are crucial for the hydrogenation of carbon dioxide to methanol. Currently, much work focuses on developing catalysts for carbon dioxide hydrogenation to methanol based on Cu-ZnO compositions. However, the reverse water-gas shift reaction is difficult to suppress in these catalysts, and they are prone to poisoning and deactivation. In contrast, oxide-based catalysts, such as ZnO-ZrO2 solid solution catalysts and In2O3 catalysts, while exhibiting good selectivity and stability, require further improvement in activity. Other catalysts, such as Co@SiO2 and MoS2, suffer from low activity or high methane content as a byproduct. Therefore, designing and synthesizing catalysts that balance activity, selectivity, and stability has become a significant challenge in the conversion of carbon dioxide to methanol. Summary of the Invention

[0004] In view of this, the technical problem to be solved by the present invention is to provide a supported anti-perovskite nitride catalyst, its preparation method and application, wherein the catalyst has high catalytic activity, selectivity and stability.

[0005] This invention provides a method for preparing a supported anti-perovskite nitride catalyst, comprising the following steps:

[0006] S1) Carbon and nitrogen monomers are thermally polymerized in air to convert them into carbon nitride materials;

[0007] S2) The carbon nitride material and the metal salt solution are mixed, dispersed, and dried to obtain the calcination precursor;

[0008] S3) The above-mentioned calcined precursor was calcined to obtain a supported anti-perovskite nitride catalyst.

[0009] The preparation method provided by this invention is simple to operate, and the prepared catalyst exhibits excellent catalytic activity and stability in the reaction of carbon dioxide hydrogenation to methanol, making it suitable for industrial application.

[0010] Preferably, the carbon-nitrogen monomer is selected from one or more of urea, cyanamide, dicyandiamide, and melamine. In some specific embodiments of the present invention, the carbon-nitrogen monomer is melamine.

[0011] Preferably, the temperature of the thermal polymerization reaction is 475–625°C, and the time of the thermal polymerization reaction is 0.5–6 hours. In some specific embodiments of the present invention, the temperature of the thermal polymerization is 550°C, and the time of the thermal polymerization is 4 hours.

[0012] The metal salt solution is preferably an aqueous solution of the metal salt.

[0013] Preferably, the metal salt is one or more of the metal ions selected from nitrates, chlorides, sulfates, and acetates; in some specific embodiments of the present invention, the metal salt is a nitrate.

[0014] The metal ions preferably include metal ion A and metal ion B; metal ion A is preferably one or more selected from iron ion, copper ion, nickel ion, cobalt ion, and chromium ion; metal ion B is preferably one or more selected from indium ion, gallium ion, zinc ion, copper ion, and aluminum ion. In some specific embodiments of the present invention, metal ion A is selected from iron ion, nickel ion, or cobalt ion; and metal ion B is indium ion.

[0015] Preferably, the molar ratio of metal ion A to metal ion B in this invention is (1-5):1, including but not limited to 1:1, 2:1, 3:1, 4:1 or 5:1. In some specific embodiments of this invention, the molar ratio of metal ion A to metal ion B is 3:1.

[0016] The dispersion is preferably ultrasonic dispersion.

[0017] The drying temperature is preferably 20-80°C, more preferably 60°C.

[0018] Preferably, the loading of metal ions in the calcined precursor is 1 wt% to 40 wt%. In some specific embodiments of the present invention, the loading of metal ions in the calcined precursor is approximately 10 wt%.

[0019] Preferably, the heating rate of the calcination is 1-10℃ / min; in some specific embodiments of the present invention, the heating rate of the calcination is 5℃ / min; the calcination temperature is preferably 300-800℃; more preferably 500-600℃; the calcination time is preferably 0-24h; more preferably 4h.

[0020] The calcination atmosphere is preferably a hydrogen / argon or hydrogen / nitrogen mixture, wherein the concentration of hydrogen is 0% to 100%. In some specific embodiments of the present invention, the calcination atmosphere is a 10% hydrogen / argon mixture.

[0021] This invention provides a supported anti-perovskite nitride catalyst prepared by the above preparation method.

[0022] The experimental results show that the above catalyst has high catalytic activity, selectivity and stability in the reaction of carbon dioxide hydrogenation to methanol.

[0023] Based on this, the present invention provides the application of the supported anti-perovskite nitride catalyst prepared by the above preparation method as a catalyst for the reaction of carbon dioxide hydrogenation to methanol.

[0024] Compared with existing technologies, this invention provides a method for preparing a supported anti-perovskite nitride catalyst, comprising the following steps: S1) thermally polymerizing carbon and nitrogen monomers in an air atmosphere to convert them into carbon nitride materials; S2) mixing, dispersing, and drying the carbon nitride materials and a metal salt solution to obtain a calcination precursor; S3) calcining the above-mentioned calcination precursor to obtain the supported anti-perovskite nitride catalyst. This invention provides a universal method for preparing a supported anti-perovskite nitride catalyst, using carbon nitride as both a carbon and nitrogen source, and obtaining a carbon-supported anti-perovskite nitride catalyst through impregnation and in-situ pyrolysis. This catalyst exhibits excellent catalytic activity and selectivity, and can achieve a high space-time yield (greater than 1 g). CH3OH / g cat It exhibits good stability ( / h). The preparation process is simple, easy to operate, and easy to repeat, showing promising application prospects. Attached Figure Description

[0025] Figure 1 The image shows the X-ray diffraction pattern of the carbon nitride material prepared in Example 1 of this invention.

[0026] Figure 2 The X-ray diffraction pattern of the carbon-supported nickel indium nitride catalyst finally prepared in Example 1 of this invention;

[0027] Figure 3 This is a transmission electron microscope (TEM) image of the carbon-supported nickel indium nitride catalyst finally prepared in Example 1 of the present invention.

[0028] Figure 4 This is a catalytic activity diagram of the carbon-supported nickel indium nitride catalyst finally obtained in Example 1 of the present invention;

[0029] Figure 5This is a comparison diagram of the activity of the carbon-supported nickel-indium nitride catalyst finally prepared in Example 1 of the present invention and the carbon-supported nickel-indium intermetallic compound catalyst finally prepared in Comparative Example 1.

[0030] Figure 6 This is a lifetime curve of the carbon-supported nickel indium nitride catalyst finally prepared in Example 1 of the present invention in the carbon dioxide hydrogenation reaction.

[0031] Figure 7 The X-ray diffraction pattern of the carbon-supported cobalt indium nitride catalyst finally prepared in Example 2 of this invention;

[0032] Figure 8 The image shows the catalytic activity of the carbon-supported cobalt indium nitride catalyst finally obtained in Example 2 of this invention.

[0033] Figure 9 The X-ray diffraction pattern of the carbon-supported cobalt indium nitride catalyst finally obtained in Example 3 of this invention;

[0034] Figure 10 The image shows the X-ray diffraction pattern of the carbon-supported iron-indium nitride catalyst finally obtained in Example 4 of this invention. Detailed Implementation

[0035] To further illustrate the present invention, the supported anti-perovskite nitride catalyst, its preparation method, and its application are described in detail below with reference to embodiments.

[0036] The reagents used in the following embodiments of the present invention, such as gases (carbon dioxide, hydrogen, argon, etc.) and reagents such as ferric nitrate, nickel nitrate, cobalt nitrate, indium nitrate, and melamine, were all purchased from the market.

[0037] Example 1

[0038] 10g of melamine was weighed and placed in a crucible, covered, and placed in a muffle furnace. The temperature was increased to 550℃ at a rate of 5℃ / min and calcined for 4 hours. After cooling to room temperature, the resulting carbon nitride material was thoroughly ground into powder for later use. 0.291g of nickel nitrate hexahydrate and 0.124g of indium nitrate tetrahydrate were weighed and dissolved in 1mL of deionized water to prepare a metal salt solution. 1.0g of carbon nitride powder was then weighed and added to the metal salt solution. The solution was ultrasonically dispersed at room temperature for 30 minutes and then dried in a 60℃ oven to obtain a calcined precursor. The calcined precursor was placed in a tube furnace and heated to 500℃ at a rate of 5℃ / min under a 10vol% H2 / Ar atmosphere. After holding at this temperature for 4 hours, it was allowed to cool naturally to obtain a carbon-supported nickel-indium nitride catalyst.

[0039] The obtained carbon nitride material was analyzed using X-ray diffraction, and the results are as follows: Figure 1As shown, there are two main diffraction peaks, which correspond to the (100) and (002) crystal planes of the carbon nitride material, respectively, confirming that the crystal structure is graphitic carbon nitride.

[0040] The final carbon-supported nickel-indium nitride catalyst was analyzed by X-ray diffraction, and the results are as follows: Figure 2 As shown, the X-ray diffraction pattern of the catalyst is similar to that of the standard anti-perovskite nitride (Ni3InN). 0.5 X-ray diffraction pattern Figure 1 This demonstrates that the method used in Example 1 of the present invention can effectively synthesize anti-perovskite-based nickel indium nitride materials.

[0041] The carbon-supported nickel-indium nitride catalyst was observed using transmission electron microscopy, and the results are as follows: Figure 3 As shown, the carbon-supported nickel indium nitride catalyst prepared in Example 1 of this invention has a nanoparticle size of about 10 nm, good dispersion, and the surface of the nanoparticles is partially coated with a carbon layer, which can effectively protect the nanoparticles from agglomeration and sintering during the high temperature and high pressure reaction process and improve the stability of the catalyst.

[0042] The catalytic performance of the prepared carbon-supported nickel-indium nitride catalyst and the carbon-supported nickel-indium intermetallic compound catalyst prepared in Comparative Example 1 were tested.

[0043] Hydrogenation tests were conducted on a flow-through fixed-bed reactor. Specifically, 100 mg of catalyst was placed in a quartz tube with an inner diameter of 5 mm, and the quartz tube was placed on the flow-through fixed-bed reactor. The reaction atmosphere was a mixture of carbon dioxide and hydrogen (gas ratio 1:3), at a pressure of 5 MPa, and at a temperature of 250 °C. The composition of the reaction products was detected in real time by online gas chromatography, and their specific catalytic activity was as follows: Figure 4 and Figure 5 As shown. From Figure 4 As can be seen, when the space velocity is 12000 mL / gcat / h, the carbon dioxide conversion rate is 19.8% and the methanol selectivity is 72.9%; when the space velocity is increased to 36000 mL / gcat / h, the carbon dioxide conversion rate is 12.0%, the methanol selectivity is 79.5%, and the methanol space-time yield (STY) is 1.1 g. CH3OH / g cat / h. From Figure 5 As can be seen, its reactivity is significantly higher than that of the ordinary carbon-supported nickel-indium intermetallic compound catalyst in Comparative Example 1. This indicates that the anti-perovskite structure formed by the introduction of nitrogen atoms into the nickel-indium intermetallic compound can significantly enhance the catalytic activity of carbon dioxide hydrogenation to methanol.

[0044] Catalyst lifetime test at reaction temperature 250℃ as follows: Figure 6As shown, the carbon dioxide conversion rate remained stable at ~20%, and the methanol selectivity remained stable at ~72%, maintaining this level for 1000 hours without significant deactivation. This indicates the protective effect of the partially encapsulated surface carbon layer formed in situ during catalyst preparation on the nanoparticles.

[0045] Example 2

[0046] 10g of melamine was weighed and placed in a crucible, covered, and placed in a muffle furnace. The temperature was increased to 550℃ at a rate of 5℃ / min and calcined for 4 hours. After cooling to room temperature, the resulting carbon nitride material was thoroughly ground into powder for later use. 0.291g of cobalt nitrate hexahydrate and 0.124g of indium nitrate tetrahydrate were weighed and dissolved in 1mL of deionized water to prepare a metal salt solution. 1.0g of carbon nitride powder was then weighed and added to the metal salt solution. The solution was ultrasonically dispersed at room temperature for 30 minutes and then dried in a 60℃ oven to obtain a calcined precursor. The calcined precursor was placed in a tube furnace and heated to 550℃ at a rate of 5℃ / min under a 10vol% H2 / Ar atmosphere. After holding at this temperature for 4 hours, it was allowed to cool naturally to obtain a carbon-supported cobalt-indium nitride catalyst.

[0047] The final catalyst was analyzed using X-ray diffraction, and the results are as follows: Figure 7 As shown, the X-ray diffraction pattern of the catalyst is similar to that of the standard anti-perovskite nitride (Co3InN). 0.5 X-ray diffraction pattern Figure 1 This demonstrates that the method used in Example 2 of the present invention can effectively synthesize anti-perovskite-based cobalt indium nitride materials.

[0048] The catalytic performance of the prepared carbon-supported cobalt indium nitride catalyst was tested.

[0049] Hydrogenation tests were conducted on a flow-through fixed-bed reactor. Specifically, 100 mg of the catalyst was placed in a quartz tube with an inner diameter of 5 mm, and the tube was placed on the flow-through fixed-bed reactor. The reaction atmosphere was a mixture of carbon dioxide and hydrogen (gas ratio 1:3), at a pressure of 5 MPa, and at a temperature of 275 °C. The composition of the reaction products was detected in real time by online gas chromatography. Its specific catalytic activity is as follows: Figure 8 As shown, when the space velocity was 12000 mL / gcat / h, the carbon dioxide conversion rate was 12.2% and the methanol selectivity was 90.9%; when the space velocity was increased to 36000 mL / gcat / h, the carbon dioxide conversion rate was 7.4%, the methanol selectivity was 94.9%, and the methanol space-time yield (STY) was 0.9 g. CH3OH / g cat / h.

[0050] Example 3

[0051] 10g of melamine was weighed and placed in a crucible, covered, and placed in a muffle furnace. The temperature was increased to 550℃ at a rate of 5℃ / min and calcined for 4 hours. After cooling to room temperature, the resulting carbon nitride material was thoroughly ground into powder for later use. 0.291g of cobalt nitrate hexahydrate and 0.124g of indium nitrate tetrahydrate were weighed and dissolved in 1mL of deionized water to prepare a metal salt solution. 1.0g of carbon nitride powder was then weighed and added to the metal salt solution. The solution was ultrasonically dispersed at room temperature for 30 minutes and then dried in a 60℃ oven to obtain a calcined precursor. The calcined precursor was placed in a tube furnace and heated to 450℃ at a rate of 5℃ / min under a 10vol% H2 / Ar atmosphere. After holding at this temperature for 4 hours, it was allowed to cool naturally to obtain a carbon-supported cobalt-indium nitride catalyst.

[0052] The final catalyst was analyzed using X-ray diffraction, and the results are as follows: Figure 9 As shown, the X-ray diffraction pattern of the catalyst is similar to that of the standard anti-perovskite nitride (Co3InN). 0.5 X-ray diffraction pattern Figure 1 This demonstrates that the method used in Example 3 of the present invention can effectively synthesize anti-perovskite-based cobalt indium nitride materials.

[0053] Example 4

[0054] 10g of melamine was weighed and placed in a crucible, covered, and placed in a muffle furnace. The temperature was increased to 550℃ at a rate of 5℃ / min and calcined for 4 hours. After cooling to room temperature, the resulting carbon nitride material was thoroughly ground into powder for later use. 0.404g of ferric nitrate nonahydrate and 0.124g of indium nitrate tetrahydrate were weighed and dissolved in 1mL of deionized water to prepare a metal salt solution. 1.0g of carbon nitride powder was then weighed and added to the metal salt solution. The solution was ultrasonically dispersed at room temperature for 30 minutes and then dried in a 60℃ oven to obtain a calcined precursor. The calcined precursor was placed in a tube furnace and heated to 600℃ at a rate of 5℃ / min under a 10vol% H2 / Ar atmosphere. After holding at this temperature for 4 hours, the solution was allowed to cool naturally to obtain a carbon-supported iron-indium nitride catalyst.

[0055] The final catalyst was analyzed using X-ray diffraction, and the results are as follows: Figure 10 As shown, the X-ray diffraction pattern of the catalyst is similar to that of the standard anti-perovskite nitride (Fe3InN). 0.5 X-ray diffraction pattern Figure 1 This demonstrates that the method used in Example 4 of the present invention can effectively synthesize anti-perovskite-based iron indium nitride materials.

[0056] Comparative Example 1

[0057] 0.582 g of nickel nitrate hexahydrate and 0.248 g of indium nitrate tetrahydrate were weighed and dissolved in 5 mL of deionized water to prepare a metal salt solution. Then, 300 mg of activated carbon powder was weighed and added to the metal salt solution. After ultrasonic dispersion at room temperature for 30 minutes, the solution was dried in a 60°C oven to obtain a calcined precursor. The calcined precursor was placed in a tube furnace and heated to 500°C at a rate of 5°C / min under a 10 vol% H₂ / Ar atmosphere. After holding at this temperature for 4 hours, the solution was allowed to cool naturally to obtain a carbon-supported nickel-indium intermetallic compound catalyst. According to inductively coupled plasma (ICP) testing results, the metal loading of the obtained carbon-supported nickel-indium intermetallic compound catalyst was similar to that of the nickel-indium nitride catalyst finally obtained in Example 1, both being ~40 wt.%.

[0058] In summary, the embodiments of the present invention can effectively synthesize anti-perovskite nitride catalysts, which not only have high activity, high selectivity and high stability, but also have simple preparation methods and low preparation costs, and can exhibit very high catalytic performance in the reaction of carbon dioxide hydrogenation to methanol.

[0059] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing a supported anti-perovskite nitride catalyst, characterized by, The preparation method comprises the following steps: S1) performing a thermal polymerization reaction on the carbon-nitrogen monomer in an air atmosphere to convert the carbon-nitrogen monomer into a carbon nitride material; the thermal polymerization reaction is performed at a temperature of 475-625°C; the thermal polymerization reaction is performed for a time period of 0.5-6h; S2) mixing and dispersing the carbon nitride material and a metal salt solution, and drying to obtain a calcined precursor; S3) calcining the calcined precursor to obtain a supported anti-perovskite nitride catalyst; the calcination is performed at a temperature increasing rate of 1-10°C / min; the calcination is performed at a temperature of 300-800°C; the calcination is performed for a time period of 4-24h; the metal ions in the metal salt in the metal salt solution comprise metal ion A and metal ion B; the metal ion A is selected from one or more of iron ions, copper ions, nickel ions, cobalt ions, and chromium ions; the metal ion B is selected from one or more of indium ions, gallium ions, zinc ions, and aluminum ions; the atmosphere for the calcination is a hydrogen / argon or hydrogen / nitrogen mixed gas atmosphere.

2. The production method according to claim 1, characterized by, the carbon-nitrogen monomer is selected from one or more of urea, monocyamide, dicyandiamide, and melamine.

3. The production method according to claim 1, characterized by, the metal salt is one or more of a nitrate salt, a chloride salt, a sulfate salt, and an acetate salt of the metal ion.

4. The method of claim 1, wherein, the molar ratio of the metal ion A to the metal ion B is (1-5):

1.

5. The preparation method according to claim 1, characterized in that, the loading amount of the metal ion in the calcined precursor is 1wt%-40wt%.

6. The supported anti-perovskite nitride catalyst prepared by the preparation method in any one of claims 1-5.

7. The use of the supported anti-perovskite nitride catalyst prepared by the preparation method in any one of claims 1-5 as a catalyst for a carbon dioxide hydrogenation reaction to produce methanol.

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