CN111151293B - Nitrogen-doped tungsten carbide catalyst, and preparation and application thereof - Google Patents

Abstract

The invention relates to the technical field of catalysis, in particular to a nitrogen-doped tungsten carbide catalyst and preparation and application thereof, and discloses the nitrogen-doped tungsten carbide catalyst which comprises a nitrogen-doped tungsten carbide active center and a carrier containing a B acid site, wherein the nitrogen-doped tungsten carbide active center is nitrogen-doped tungsten carbide nano particles, the particle size is less than or equal to 10nm, and CO can be used for removing CO ₂ The product is converted into ethanol and propanol products with high added values, so that the conversion rate and the selectivity of ethanol and propanol are remarkably improved; the preparation method adopts a co-impregnation preparation method, is simple and convenient, does not need to strictly control the concentration of a metal salt solution, and has reasonable content matching of C and N in the active center of the prepared catalyst, so that the catalyst has higher activity and stability; regulation of W ₂ Electronic structure in C, thereby effectively regulating and controlling CO ₂ The C-C bond generation rate and the C-O bond breakage rate in the hydrogenation process greatly reduce the selectivity of C1 products, improve the selectivity of ethanol and propanol products and have wide application prospect.

Description

A kind of nitrogen-doped tungsten carbide catalyst and its preparation and application

technical field

The invention relates to the technical field of catalysis, in particular to a nitrogen-doped tungsten carbide catalyst and its preparation and application.

Background technique

Ethanol and propanol are very important organic solvents and basic chemical raw materials, and their uses are very extensive. Ethanol can be used to manufacture chemical raw materials such as acetaldehyde, ether, ethyl acetate, ethylamine, etc., and can also be transferred into gasoline as a vehicle fuel; Alcohol can be used to synthesize bulk chemicals such as propyl acetate, glycol ether, and propylamine, as well as pharmaceutical and pesticide supplies such as propylparaben, perfluoropropionic acid, and trifluralin; ethanol and propanol are used in the defense industry , Medical and health, organic synthesis, food industry, industrial and agricultural production have a wide range of uses.

The existing ethanol preparation methods mainly include fermentation method, ethylene hydration method, coal chemical industry, and synthesis gas direct ethanol production method. However, the traditional fermentation method takes a long time and has low efficiency; while methods such as ethylene hydration, coal chemical industry, and synthesis gas to ethanol directly have relatively high costs. Industrially, propanol is mostly produced by hydration reaction of propylene under high temperature and pressure, but the conversion rate of propylene in this method is low and the production cost is relatively high.

_CO2 is a direct product of fossil fuel combustion and is extremely abundant on Earth. However, the continuous development of human society has led to a sharp increase in the use of fossil fuels and an increase in the CO ₂ content in the atmosphere, which not only intensifies the greenhouse effect, but also causes a huge waste of carbon resources. Catalytic conversion of CO ₂ into high value-added ethanol and propanol is one of the important technical means for resource utilization of CO ₂ , and it is of great significance to solve the two new challenges of climate change and energy crisis that human society is facing today.

So far, there are few reaction systems for heterogeneously catalyzed _CO2 hydrogenation to ethanol and propanol. Wang Liang et al. used CoAlO _x as a catalyst to convert _CO2 into ethanol, propanol and other products under the reaction conditions of 100 °C and 4 MPa. The conversion rate of _CO2 was 28.9%, and the selectivity of ethanol in liquid alcohol products was 62.7%, but the selectivity in the total product is only 2.82% (CN108380216A); People such as Zhenhong He use Pt/Co ₃ O ₄ as catalyst, in the mixed solvent of DMI and H ₂ O, at 200 ℃, 8MPa Under the reaction conditions, _CO2 is converted into C2 ⁺ alcohols, wherein the selectivities of ethanol and propanol in the liquid alcohol products are 29% and 5.2%, respectively, but the selectivity in the total product is less than 11.3% (Angew.Chem.Int. Ed., 2016, 55, 737-741); Shuxing Bai et al. used Pd-Cu supported on P25 as a bimetallic catalyst to convert CO ₂ into ethanol at 200°C, and ethanol was in liquid The selectivity among alcohol products reaches up to 92% (J.Am.Chem.Soc., 2017, 139, 6827-6830).

At present, in the process of heterogeneously catalyzed _CO2 catalytic hydrogenation to ethanol and propanol, although the selectivity of ethanol and propanol in liquid alcohol products is relatively high, the main products of the reaction are still CO and _CH4 Or C ₁ products such as methyl alcohol, the selectivity of ethanol, propanol in the total product after reaction is still lower (<20%). This is mainly because, on the one hand, _CO2 is a molecule with an extremely stable chemical structure, and it is difficult to achieve effective activation; on the other hand, it is difficult to form CC bonds in a controlled manner while maintaining the C-OH bond structure during _CO2 hydrogenation reaction. Obtain ethanol or propanol, cause the main product after reaction to be C1 compound or long-chain alkane. The currently developed catalytic reaction system is still unable to achieve a high conversion rate of CO ₂ and a high selectivity of ethanol and propanol products. Therefore, the conversion of _CO2 into high value-added C2 ⁺ alcohols such as ethanol or propanol remains a huge challenge.

Contents of the invention

Therefore, the technical problem to be solved in the present invention is to overcome the problems of low conversion rate and low selectivity of _CO2 catalytic hydrogenation to ethanol and propanol process in the prior art, _and reasonably match the generation rate and C-OH bond breaking rate, thus providing a supported tungsten carbide catalyst as a catalyst for the production of ethanol and propanol products with high activity and high selectivity of _CO2 .

The invention discloses a nitrogen-doped tungsten carbide catalyst, which comprises a carrier and a nitrogen-doped tungsten carbide active component loaded on the carrier, the carrier contains B acid sites, and the nitrogen-doped tungsten carbide active component is Nitrogen-doped tungsten carbide nanoparticles with particle size ≤10nm.

The invention also discloses a raw material composition for preparing the nitrogen-doped tungsten carbide catalyst, including soluble tungsten salt, methylene amine organic matter and B acid carrier, wherein the molar ratio of tungsten salt and methylene amine is 1:0.5-1:5.

Optionally, the content of tungsten is 5wt%-50wt%, and the content of nitrogen is 0.5wt%-5wt%.

Optionally, the soluble tungsten salt includes one of ammonium metatungstate, ammonium paratungstate, sodium tungstate and phosphotungstic acid.

Optionally, the methylene amine organic compound is one of hexamethylenediamine, hexamethylenetetramine, tetramethylenediamine and trimethylhexamethylenediamine.

Optionally, the B acid site carrier includes a molecular sieve carrier containing a B acid site, including one of ZSM-5 carrier, Y carrier, Beta carrier and MOR carrier.

Optionally, an auxiliary agent is also included, the auxiliary agent includes at least one of Cu, Co, In and Fe, and the content of the auxiliary agent is 0.5wt%-5wt%.

The invention also discloses a method for preparing the nitrogen-doped tungsten carbide catalyst or the nitrogen-doped tungsten carbide catalyst prepared from the raw material composition for preparing the nitrogen-doped tungsten carbide catalyst, which includes the following steps:

(1) Take soluble tungsten salt, methylene amine organic matter and water to prepare a mixed solution, impregnate the mixed solution on a carrier containing B acid sites, and then dry at 80-120°C to obtain a catalyst precursor;

(2) Place the precursor in a mixed gas atmosphere containing hydrogen and heat it up to 600-900°C for 2-12 hours to obtain a supported nitrogen-doped tungsten carbide catalyst, wherein the temperature-programmed temperature rise rate is 0.5-2 °C/min.

Optionally, the mixed gas further includes at least one of nitrogen, argon and helium, and the volume fraction of hydrogen is 10-50%.

The invention also discloses the nitrogen-doped tungsten carbide catalyst, or the carbon-doped tungsten carbide catalyst prepared from the raw material composition for preparing the nitrogen-doped tungsten carbide catalyst, or the nitrogen-doped tungsten carbide catalyst prepared The nitrogen-doped catalyst prepared by the method is applied in the field of carbon dioxide hydrogenation to alcohol.

The invention also discloses a method for catalytic carbon dioxide hydrogenation to produce alcohol. _CO2 and _H2 with a volume ratio of 1:3-1:4 are reacted to generate alcohol under the action of a catalyst, wherein the catalyst is claim 1 or The nitrogen-doped tungsten carbide catalyst described in 2, or the nitrogen-doped catalyst prepared by the method for preparing the nitrogen-doped tungsten carbide catalyst described in claim 8 or 9.

Optionally, the reaction temperature of the catalytic reaction is 200-350°C.

Optionally, the reaction pressure of the catalytic reaction is 0.5-10 MPa.

Optionally, the volume space velocity of the catalytic reaction is 1000-10000h ^-1 .

The technical solution of the present invention has the following advantages:

1. The present invention discloses a nitrogen-doped tungsten carbide catalyst (N-W2C/B), which includes a nitrogen-doped tungsten carbide active center and a carrier, the carrier contains B acid sites, and the nitrogen-doped tungsten carbide active center is nitrogen-doped carbide Tungsten nanoparticles, nitrogen-doped tungsten carbide nanoparticles with a particle size of ≤10nm, loaded on a carrier; the nanometer size significantly enhances the activity of the catalyst, without the use of precious metals, and can convert _CO2 into high value-added ethanol and propanol products , significantly improving the conversion of _CO2 and the selectivity of ethanol to propanol. Among them, the carrier is preferably a molecular sieve containing B acid sites, which has a large specific surface area, and the nitrogen-doped tungsten carbide active centers are evenly distributed in the pore diameter, and the catalytic performance is good and stable.

2. The preparation method of nitrogen-doped tungsten carbide catalyst (N-W2C/B) provided by the present invention adopts the co-impregnation preparation method, which is simple and convenient, and uses methylene amine as the carbon source and nitrogen source, avoiding the traditional tungsten carbide synthesis process The carbon deposition problem of the catalyst caused by the cracking of _CH in the gas at high temperature makes the catalyst have higher activity and stability in the _CO catalytic hydrogenation reaction; the temperature-programmed carbonization preparation method adopted by the present invention provides N-W /B catalyst, through the reasonable matching of the content of C and N in the active center, the electronic structure in W ₂ C can be adjusted, so as to effectively control the formation rate of CC bond and the break rate of CO bond in the process of CO ₂ hydrogenation, thus greatly reducing the selection of C1 products It improves the selectivity of ethanol and propanol products.

3. The application of the nitrogen-doped tungsten carbide catalyst (N-W2C/B) provided by the present invention in the _CO2 hydrogenation process has changed the current preparation methods of ethanol and propanol, compared with the traditional fermentation method, ethylene water Carbon dioxide has a rich carbon source, and it can be catalytically hydrogenated into high value-added ethanol and propanol; it can solve the problem of carbon balance imbalance and has broad application prospects.

Description of drawings

In order to more clearly illustrate the specific implementation of the present invention or the technical solutions in the prior art, the following will briefly introduce the accompanying drawings that need to be used in the specific implementation or description of the prior art. Obviously, the accompanying drawings in the following description The drawings show some implementations of the present invention, and those skilled in the art can obtain other drawings based on these drawings without any creative work.

Fig. 1 is the electron micrograph of nitrogen-doped tungsten carbide catalyst described in embodiment 1;

Fig. 2 is the electron micrograph of nitrogen-doped tungsten carbide catalyst described in embodiment 2;

Fig. 3 is the electron micrograph of nitrogen-doped tungsten carbide catalyst described in embodiment 3;

Fig. 4 is the electron micrograph of nitrogen-doped tungsten carbide catalyst described in embodiment 4;

Fig. 5 is the electron micrograph of nitrogen-doped tungsten carbide catalyst described in embodiment 5;

Fig. 6 is the electron micrograph of nitrogen-doped tungsten carbide catalyst described in embodiment 6;

Fig. 7 is the electron micrograph of nitrogen-doped tungsten carbide catalyst described in embodiment 7;

Fig. 8 is an electron micrograph of the nitrogen-doped tungsten carbide catalyst described in Example 8.

Detailed ways

The following examples are provided in order to further understand the present invention better, are not limited to the best implementation mode, and do not limit the content and protection scope of the present invention, anyone under the inspiration of the present invention or use the present invention Any product identical or similar to the present invention obtained by combining features of other prior art falls within the protection scope of the present invention.

If no specific experimental steps or conditions are indicated in the examples, it can be carried out according to the operation or conditions of the conventional experimental steps described in the literature in this field. The reagents or instruments used, whose manufacturers are not indicated, are all commercially available conventional reagent products.

Example 1

This example discloses a specific implementation of a nitrogen-doped tungsten carbide catalyst (NW ₂ C/B), including the following steps:

Add 10mmol ammonium metatungstate and 8mmol hexamethylenediamine into water to mix the solution, impregnate the mixed solution with an equal volume on 5g of HZSM-5 molecular sieve containing B acid sites, let it stand at room temperature for 12h, and then put it in the oven After drying at 100°C for 24 hours, the precursor of nitrogen-doped tungsten carbide catalyst was obtained. The mass fraction of tungsten element in the precursor was measured to be 27%, and the mass fraction of nitrogen element was 0.5%;

The precursor was heated to 600°C for carbonization in a mixed gas of hydrogen and nitrogen for 4h, wherein the volume fraction of hydrogen in the mixed gas was 10%, and the rate of temperature increase was 1.5°C/min to obtain a nitrogen-doped tungsten carbide catalyst (NW ₂ C/B), as shown in Figure 1, wherein the particle size of nitrogen-doped tungsten carbide nanoparticles is 5-7nm.

Example 2

This example discloses a specific implementation of a nitrogen-doped tungsten carbide catalyst (NW ₂ C/B), including the following steps:

Add 6.8mmol of ammonium metatungstate and 20.4mmol of hexamethylenediamine into water to mix the solution, impregnate the mixed solution on 5g of H-β molecular sieve containing B acid sites, let it stand at room temperature for 12h, and then put it in the oven After drying at 80°C for 18 hours, the precursor of the nitrogen-doped tungsten carbide catalyst was obtained, and the mass fraction of tungsten element in the precursor was measured to be 20%, and the mass fraction of nitrogen element was 1%;

The precursor was heated to 800°C for carbonization in a mixed gas of hydrogen and helium for 4h, wherein the volume fraction of hydrogen in the mixed gas was 30%, and the rate of temperature increase was 2.0°C/min to obtain a nitrogen-doped tungsten carbide catalyst ( NW ₂ C/B), as shown in Fig. 2, wherein the nitrogen-doped tungsten carbide nanoparticles have a particle size of 5-9nm.

Example 3

This example discloses a specific implementation of a nitrogen-doped tungsten carbide catalyst (NW ₂ C/B), including the following steps:

Add 15.3mmol of ammonium metatungstate and 19.2mmol of hexamethylenediamine into water to mix the solution, impregnate the mixed solution on 5g of H-Y molecular sieve containing B acid sites, let it stand at room temperature for 12h, and then place it in an oven at 120°C After drying for 24 hours, the precursor of nitrogen-doped tungsten carbide catalyst was obtained, and the mass fraction of tungsten element in the precursor was measured to be 36%, and the mass fraction of nitrogen element was 0.8%;

The precursor was heated to 700°C for 2h in a mixed gas of hydrogen and nitrogen for carbonization, wherein the volume fraction of hydrogen in the mixed gas was 40%, and the rate of temperature increase was 1.0°C/min, to obtain a nitrogen-doped tungsten carbide catalyst (NW ₂ C/B), as shown in Figure 3, wherein the nitrogen-doped tungsten carbide nanoparticles have a particle size of 5-8nm.

Example 4

This example discloses a specific implementation of a nitrogen-doped tungsten carbide catalyst (NW ₂ C/B), including the following steps:

Add 1.4mmol of ammonium metatungstate and 4.0mmol of hexamethylenediamine to the mixed solution in water, impregnate the mixed solution on 5g of MOR type molecular sieve containing B acid sites, let it stand at room temperature for 12h, and then place it in an oven at 100°C After drying for 24 hours, the precursor of the nitrogen-doped tungsten carbide catalyst was obtained, and the mass fraction of the tungsten element in the precursor was measured to be 5%, and the mass fraction of the nitrogen element was 0.6%;

The precursor was heated to 650° C. for 12 hours in a mixed gas of hydrogen and argon, wherein the volume fraction of hydrogen in the mixed gas was 20%, and the temperature programmed rate was 0.5° C./min to obtain a nitrogen-doped tungsten carbide catalyst ( NW ₂ C/B), as shown in Fig. 4, wherein the nitrogen-doped tungsten carbide nanoparticles have a particle size of 5-7nm.

Example 5

This example discloses a specific implementation of a nitrogen-doped tungsten carbide catalyst (NW ₂ C/B), including the following steps:

Add 3.7mmol of ammonium metatungstate and 15.6mmol of hexamethylenediamine to the mixed solution in water, impregnate the mixed solution on 5g of H-β molecular sieve containing B acid sites, let it stand at room temperature for 12h, and then put it in the oven After drying at 100°C for 30 hours, the precursor of the nitrogen-doped tungsten carbide catalyst was obtained. The mass fraction of tungsten element in the precursor was measured to be 12%, and the mass fraction of nitrogen element was 2%;

The precursor was heated to 750° C. for carbonization in a mixed gas of hydrogen and argon for 4 h, wherein the volume fraction of hydrogen in the mixed gas was 15%, and the temperature programmed rate was 2.5° C./min to obtain a nitrogen-doped tungsten carbide catalyst ( NW ₂ C/B), as shown in Fig. 5, wherein the nitrogen-doped tungsten carbide nanoparticles have a particle size of 3-5nm.

Example 6

This example discloses a specific implementation of a nitrogen-doped tungsten carbide catalyst (NW ₂ C/B), including the following steps:

Add 22.3mmol of ammonium metatungstate and 80.1mmol of hexamethylenediamine to the mixed solution in water, impregnate the mixed solution on 5g of HZSM-5 molecular sieve containing B acid sites, let it stand at room temperature for 12h, and then put it in the oven After drying at 100°C for 24 hours, the precursor of the nitrogen-doped tungsten carbide catalyst was obtained, and the mass fraction of tungsten element in the precursor was measured to be 45%, and the mass fraction of nitrogen element was 5%;

The precursor was heated to 680° C. for carbonization in a mixed gas of hydrogen and argon for 4 h, wherein the volume fraction of hydrogen in the mixed gas was 35%, and the temperature programmed rate was 3.0° C./min to obtain a nitrogen-doped tungsten carbide catalyst ( NW ₂ C/B), as shown in Fig. 6, wherein the nitrogen-doped tungsten carbide nanoparticles have a particle size of 3-5nm.

Example 7

This example discloses a specific implementation of a nitrogen-doped tungsten carbide catalyst (NW ₂ C/B), including the following steps:

Add 6.0mmol ammonium metatungstate and 30.0mmol hexamethylenediamine into water to mix the solution, impregnate the mixed solution on 5g of H-Y type molecular sieve containing B acid sites, let it stand at room temperature for 12h, and then place it in an oven at 100°C After drying for 24 hours, the precursor of nitrogen-doped tungsten carbide catalyst was obtained, and the mass fraction of tungsten element in the precursor was measured to be 18%, and the mass fraction of nitrogen element was 2.5%;

The precursor was heated to 730° C. for carbonization in a mixed gas of hydrogen and argon for 4 h, wherein the volume fraction of hydrogen in the mixed gas was 25%, and the temperature programmed rate was 2.5° C./min to obtain a nitrogen-doped tungsten carbide catalyst ( NW ₂ C/B), as shown in FIG. 7 , wherein the nitrogen-doped tungsten carbide nanoparticles have a particle size of 6-10 nm.

Example 8

This example discloses a specific implementation of a nitrogen-doped tungsten carbide catalyst (NW ₂ C/B), including the following steps:

Add 27.2mmol of ammonium metatungstate and 13.6mmol of hexamethylenediamine into the mixed solution in water, impregnate the mixed solution on the MOR type molecular sieve containing B acid sites, let it stand at room temperature for 12h, and then dry it in an oven at 100°C After 24 hours, the precursor of the nitrogen-doped tungsten carbide catalyst was obtained, and the mass fraction of the tungsten element in the precursor was measured to be 50%, and the mass fraction of the nitrogen element was 1.8%;

The precursor was heated to 780° C. for carbonization in a mixed gas of hydrogen and argon for 4 h, wherein the volume fraction of hydrogen in the mixed gas was 50%, and the temperature programmed rate was 1.5° C./min to obtain a nitrogen-doped tungsten carbide catalyst ( NW ₂ C/B), as shown in FIG. 8 , wherein the nitrogen-doped tungsten carbide nanoparticles have a particle size of 6-8nm.

Example 9

This example discloses a specific implementation of a nitrogen-doped tungsten carbide catalyst (Cu-NW ₂ C/B) containing copper additives, including the following steps:

Add 16mmol ammonium metatungstate, 24mmol hexamethylenediamine and 0.45mmol copper nitrate to the mixed solution in water, impregnate the mixed solution on the HZSM-5 molecular sieve containing B acid sites, let it stand at room temperature for 12h, and then After drying in an oven at 100° C. for 24 hours, the precursor of nitrogen-doped tungsten carbide catalyst was obtained. The mass fraction of tungsten element in the precursor was measured to be 36%, the mass fraction of nitrogen element was 1.6%, and the mass fraction of copper element was 0.5%;

The precursor was heated to 750°C for carbonization in a mixed gas of hydrogen and argon for 4 hours, wherein the volume fraction of hydrogen in the mixed gas was 50%, and the rate of temperature increase was 1°C/min to obtain a nitrogen-doped solution containing copper additives. Heterotungsten carbide catalyst (Cu—NW ₂ C/B).

Example 10

This example discloses a specific implementation of a nitrogen-doped tungsten carbide catalyst (Co-NW ₂ C/B) containing a cobalt additive, including the following steps:

Add 17mmol of ammonium metatungstate, 41.5mmol of hexamethylenediamine and 1.2mmol of cobalt nitrate into water to mix the solution, impregnate the mixed solution on the MOR type molecular sieve containing B acid sites, let it stand at room temperature for 12h, and then After drying in an oven at 100°C for 24 hours, the precursor of nitrogen-doped tungsten carbide catalyst was obtained. The mass fraction of tungsten element in the precursor was measured to be 38%, the mass fraction of nitrogen element was 2.1%, and the mass fraction of cobalt element was 2.3%;

The precursor was heated to 700°C for carbonization in a mixed gas of hydrogen and argon for 6 hours, wherein the volume fraction of hydrogen in the mixed gas was 50%, and the rate of temperature increase was 1.5°C/min to obtain a nitrogen-doped carbon containing cobalt additive. Heterotungsten carbide catalyst (Co-NW ₂ C/B).

Example 11

This example discloses a specific implementation of a nitrogen-doped tungsten carbide catalyst (In-NW ₂ C/B) containing an indium additive, including the following steps:

Add 9.5mmol of ammonium metatungstate, 33.5mmol of hexamethylenediamine and 2.4mmol of indium nitrate into water to mix the solution, impregnate the mixed solution on the H-β molecular sieve containing B acid sites, and let it stand at room temperature for 12h , then dry at 100°C in an oven for 24h to obtain the precursor of the nitrogen-doped tungsten carbide catalyst. The mass fraction of the tungsten element in the precursor is measured to be 25%, the mass fraction of the nitrogen element is 2.5%, and the mass fraction of the indium element is 5.0%;

The precursor was heated to 680°C for 6 hours in a mixed gas of hydrogen and argon, where the volume fraction of hydrogen in the mixed gas was 35%, and the rate of temperature increase was 2.0°C/min. Heterotungsten carbide catalyst (In-NW ₂ C/B).

Example 12

This example discloses a specific implementation of a nitrogen-doped tungsten carbide catalyst (Fe-NW ₂ C/B) containing an iron promoter, including the following steps:

Add 4.8mmol of ammonium metatungstate, 21.5mmol of hexamethylenediamine and 3.2mmol of ferric nitrate into water to mix the solution, impregnate the mixed solution on the H-Y type molecular sieve containing B acid sites, let it stand at room temperature for 12h, and then After drying in an oven at 100°C for 24 hours, the precursor of nitrogen-doped tungsten carbide catalyst was obtained. The mass fraction of tungsten element in the precursor was measured to be 14.5%, the mass fraction of nitrogen element was 1.4%, and the mass fraction of iron element was 3.3%. ;

The precursor was heated to 720°C for 4 hours in a mixed gas of hydrogen and argon for carbonization, wherein the volume fraction of hydrogen in the mixed gas was 15%, and the rate of temperature increase was 2.0°C/min, to obtain a nitrogen-doped Heterotungsten carbide catalyst (Fe-NW ₂ C/B).

Example 13

This example provides a specific implementation of the nitrogen-doped tungsten carbide catalyst described in Example 1 for hydrogenation of carbon dioxide to alcohol, including the following steps:

The nitrogen-doped tungsten carbide catalyst was granulated to 70 mesh, placed in a fixed-bed reactor with an inner diameter of 10mm, and the feed gas for the catalytic reaction was CO2 _{and H2} Mixed gas, the volume ratio was 1:3, The reaction temperature of the catalytic reaction is 200°C; the reaction pressure of the catalytic reaction is 3MPa; the volume space velocity of the catalytic reaction is 2000h ^-1 ;

The outlet pipeline of the reactor is passed through two gas chromatographs in the 100°C insulation tube, and the qualitative and quantitative analysis of the raw gas CO ₂ and H ₂ and the product ethanol and propanol are carried out respectively.

Example 14

This example provides a specific implementation of the nitrogen-doped tungsten carbide catalyst described in Example 2 for hydrogenation of carbon dioxide to alcohol, including the following steps:

The nitrogen-doped tungsten carbide catalyst was granulated to 60 mesh, placed in a fixed-bed reactor with an inner diameter of 10mm, and the feed gas for the catalytic reaction was CO2 _{and H2} Mixed gas, the volume ratio was 1:3.6, The reaction temperature of the catalytic reaction is 240°C; the reaction pressure of the catalytic reaction is 4MPa; the volume space velocity of the catalytic reaction is 4000h ^-1 ;

The outlet pipeline of the reactor is passed through two gas chromatographs in the 100°C insulation tube, and the qualitative and quantitative analysis of the raw gas CO ₂ and H ₂ and the product ethanol and propanol are carried out respectively.

Example 15

This example provides a specific implementation of the nitrogen-doped tungsten carbide catalyst described in Example 2 for hydrogenation of carbon dioxide to alcohol, including the following steps:

The nitrogen-doped tungsten carbide catalyst was granulated to 80 mesh, placed in a fixed-bed reactor with an inner diameter of 10mm, and the feed gas for the catalytic reaction was CO2 _{and H2} Mixed gas, the volume ratio was 1:3.2, The reaction temperature of the catalytic reaction is 280°C; the reaction pressure of the catalytic reaction is 2.6MPa; the volume space velocity of the catalytic reaction is 8000h ^-1 ;

The outlet pipeline of the reactor is passed through two gas chromatographs in the 100°C insulation tube, and the qualitative and quantitative analysis of the raw gas CO ₂ and H ₂ and the product ethanol and propanol are carried out respectively.

Example 16

This example provides a specific implementation of the nitrogen-doped tungsten carbide catalyst described in Example 4 for hydrogenation of carbon dioxide to alcohol, including the following steps:

The nitrogen-doped tungsten carbide catalyst was granulated to 70 mesh, placed in a fixed-bed reactor with an inner diameter of 10mm, and the feed gas for the catalytic reaction was CO2 _{and H2} Mixed gas, the volume ratio was 1:3.5, The reaction temperature of the catalytic reaction is 300°C; the reaction pressure of the catalytic reaction is 3.5MPa; the volume space velocity of the catalytic reaction is 1000h ^-1 ;

The outlet pipeline of the reactor is passed through two gas chromatographs in the 100°C insulation tube, and the qualitative and quantitative analysis of the raw gas CO ₂ and H ₂ and the product ethanol and propanol are carried out respectively.

Example 17

This example provides a specific implementation of the nitrogen-doped tungsten carbide catalyst described in Example 3 for hydrogenation of carbon dioxide to alcohol, including the following steps:

The nitrogen-doped tungsten carbide catalyst was granulated to 70 mesh, placed in a fixed-bed reactor with an inner diameter of 10mm, and the feed gas for the catalytic reaction was CO2 _{and H2} Mixed gas, the volume ratio was 1:4, The reaction temperature of the catalytic reaction is 260°C; the reaction pressure of the catalytic reaction is 8.5MPa; the volume space velocity of the catalytic reaction is 3000h ^-1 ;

The outlet pipeline of the reactor is passed through two gas chromatographs in the 100°C insulation tube, and the qualitative and quantitative analysis of the raw gas CO ₂ and H ₂ and the product ethanol and propanol are carried out respectively.

Example 18

This example provides a specific implementation of the nitrogen-doped tungsten carbide catalyst described in Example 7 for carbon dioxide hydrogenation to alcohol, including the following steps:

The nitrogen-doped tungsten carbide catalyst was granulated to 70 mesh, placed in a fixed-bed reactor with an inner diameter of 10mm, and the feed gas for the catalytic reaction was CO2 _{and H2} Mixed gas, the volume ratio was 1:3.5, The reaction temperature of the catalytic reaction is 250°C; the reaction pressure of the catalytic reaction is 6.8MPa; the volume space velocity of the catalytic reaction is 9000h ^-1 ;

The outlet pipeline of the reactor is passed through two gas chromatographs in the 100°C insulation tube, and the qualitative and quantitative analysis of the raw gas CO ₂ and H ₂ and the product ethanol and propanol are carried out respectively.

Example 19

This example provides a specific implementation of the nitrogen-doped tungsten carbide catalyst described in Example 8 for hydrogenation of carbon dioxide to alcohol, including the following steps:

The nitrogen-doped tungsten carbide catalyst was granulated to 70 mesh, placed in a fixed-bed reactor with an inner diameter of 10mm, and the feed gas for the catalytic reaction was CO2 _{and H2} Mixed gas, the volume ratio was 1:3.6, The reaction temperature of the catalytic reaction is 320°C; the reaction pressure of the catalytic reaction is 5.6MPa; the volume space velocity of the catalytic reaction is 10000h ^-1 ;

The outlet pipeline of the reactor is passed through two gas chromatographs in the 100°C insulation tube, and the qualitative and quantitative analysis of the raw gas CO ₂ and H ₂ and the product ethanol and propanol are carried out respectively.

Example 20

This example provides a specific implementation of the nitrogen-doped tungsten carbide catalyst described in Example 5 for hydrogenation of carbon dioxide to alcohol, including the following steps:

The nitrogen-doped tungsten carbide catalyst was granulated to 70 mesh, placed in a fixed-bed reactor with an inner diameter of 10mm, and the feed gas for the catalytic reaction was CO2 _{and H2} Mixed gas, the volume ratio was 1:3.4, The reaction temperature of the catalytic reaction is 300°C; the reaction pressure of the catalytic reaction is 0.5MPa; the volume space velocity of the catalytic reaction is 5000h ^-1 ;

The outlet pipeline of the reactor is passed through two gas chromatographs in the 100°C insulation tube, and the qualitative and quantitative analysis of the raw gas CO ₂ and H ₂ and the product ethanol and propanol are carried out respectively.

Example 21

This example provides a specific implementation of the nitrogen-doped tungsten carbide catalyst described in Example 6 for hydrogenation of carbon dioxide to alcohol, including the following steps:

The nitrogen-doped tungsten carbide catalyst was granulated to 70 mesh, placed in a fixed-bed reactor with an inner diameter of 10mm, and the feed gas for the catalytic reaction was CO2 _{and H2} Mixed gas, the volume ratio was 1:3.6, The reaction temperature of the catalytic reaction is 330°C; the reaction pressure of the catalytic reaction is 6.3MPa; the volume space velocity of the catalytic reaction is 6000h ^-1 ;

The outlet pipeline of the reactor is passed through two gas chromatographs in the 100°C insulation tube, and the qualitative and quantitative analysis of the raw gas CO ₂ and H ₂ and the product ethanol and propanol are carried out respectively.

Example 22

This example provides a specific implementation of the nitrogen-doped tungsten carbide catalyst described in Example 3 for hydrogenation of carbon dioxide to alcohol, including the following steps:

The nitrogen-doped tungsten carbide catalyst was granulated to 70 mesh, placed in a fixed-bed reactor with an inner diameter of 10mm, and the feed gas for the catalytic reaction was CO2 _{and H2} Mixed gas, the volume ratio was 1:3.9, The reaction temperature of the catalytic reaction is 350°C; the reaction pressure of the catalytic reaction is 4.5MPa; the volume space velocity of the catalytic reaction is 4800h ^-1 ;

The outlet pipeline of the reactor is passed through two gas chromatographs in the 100°C insulation tube, and the qualitative and quantitative analysis of the raw gas CO ₂ and H ₂ and the product ethanol and propanol are carried out respectively.

Example 23

This example provides a specific implementation of the nitrogen-doped tungsten carbide catalyst described in Example 4 for hydrogenation of carbon dioxide to alcohol, including the following steps:

The nitrogen-doped tungsten carbide catalyst was granulated to 70 mesh, placed in a fixed-bed reactor with an inner diameter of 10mm, and the feed gas for the catalytic reaction was CO2 _{and H2} Mixed gas, the volume ratio was 1:3.1, The reaction temperature of the catalytic reaction is 320°C; the reaction pressure of the catalytic reaction is 1.5MPa; the volume space velocity of the catalytic reaction is 6400h ^-1 ;

The outlet pipeline of the reactor is passed through two gas chromatographs in the 100°C insulation tube, and the qualitative and quantitative analysis of the raw gas CO ₂ and H ₂ and the product ethanol and propanol are carried out respectively.

Example 24

This example provides a specific implementation of the nitrogen-doped tungsten carbide catalyst described in Example 6 for hydrogenation of carbon dioxide to alcohol, including the following steps:

The nitrogen-doped tungsten carbide catalyst was granulated to 70 mesh, placed in a fixed-bed reactor with an inner diameter of 10mm, and the feed gas for the catalytic reaction was CO2 _{and H2} Mixed gas, the volume ratio was 1:3.8, The reaction temperature of the catalytic reaction is 310°C; the reaction pressure of the catalytic reaction is 9.2MPa; the volume space velocity of the catalytic reaction is 3500h ^-1 ;

The outlet pipeline of the reactor is passed through two gas chromatographs in the 100°C insulation tube, and the qualitative and quantitative analysis of the raw gas CO ₂ and H ₂ and the product ethanol and propanol are carried out respectively.

Example 25

This example provides a specific implementation of the nitrogen-doped tungsten carbide catalyst described in Example 3 for hydrogenation of carbon dioxide to alcohol, including the following steps:

The nitrogen-doped tungsten carbide catalyst was granulated to 70 mesh, placed in a fixed-bed reactor with an inner diameter of 10mm, and the feed gas for the catalytic reaction was CO2 _{and H2} Mixed gas, the volume ratio was 1:3.2, The reaction temperature of the catalytic reaction is 290°C; the reaction pressure of the catalytic reaction is 10MPa; the volume space velocity of the catalytic reaction is 7200h ^-1 ;

The outlet pipeline of the reactor is passed through two gas chromatographs in the 100°C insulation tube, and the qualitative and quantitative analysis of the raw gas CO ₂ and H ₂ and the product ethanol and propanol are carried out respectively.

Example 26

This example provides a specific implementation of the nitrogen-doped tungsten carbide catalyst described in Example 5 for hydrogenation of carbon dioxide to alcohol, including the following steps:

The nitrogen-doped tungsten carbide catalyst was granulated to 70 mesh, placed in a fixed-bed reactor with an inner diameter of 10mm, and the feed gas for the catalytic reaction was CO2 _{and H2} Mixed gas, the volume ratio was 1:3.7, The reaction temperature of the catalytic reaction is 340°C; the reaction pressure of the catalytic reaction is 7.6MPa; the volume space velocity of the catalytic reaction is 1800h ^-1 ;

The outlet pipeline of the reactor is passed through two gas chromatographs in the 100°C insulation tube, and the qualitative and quantitative analysis of the raw gas CO ₂ and H ₂ and the product ethanol and propanol are carried out respectively.

Example 27

This example provides a specific implementation of the nitrogen-doped tungsten carbide catalyst containing cobalt promoter described in Example 10 for hydrogenation of carbon dioxide to alcohol, including the following steps:

The nitrogen-doped tungsten carbide catalyst containing cobalt additives is granulated to 70 meshes, and placed in a fixed-bed reactor with an inner diameter of 10mm. The raw gas for the catalytic reaction is CO2 _{and H2} Mixed gas, the volume ratio 1:3.5, the reaction temperature of the catalytic reaction is 330°C; the reaction pressure of the catalytic reaction is 3.6MPa; the volume space velocity of the catalytic reaction is 4800h ^-1 ;

The outlet pipeline of the reactor is passed through two gas chromatographs in the 100°C insulation tube, and the qualitative and quantitative analysis of the raw gas CO ₂ and H ₂ and the product ethanol and propanol are carried out respectively.

Example 28

This example provides a specific implementation of the nitrogen-doped tungsten carbide catalyst containing indium additive described in Example 11 for hydrogenation of carbon dioxide to alcohol, including the following steps:

The nitrogen-doped tungsten carbide catalyst containing indium additives is granulated to 70 meshes, and placed in a fixed-bed reactor with an inner diameter of 10mm. The raw material gas for the catalytic reaction is CO2 _{and H2} Mixed gas, the volume ratio 1:3, the reaction temperature of the catalytic reaction is 320°C; the reaction pressure of the catalytic reaction is 4.6MPa; the volume space velocity of the catalytic reaction is 6000h ^-1 ;

The outlet pipeline of the reactor is passed through two gas chromatographs in the 100°C insulation tube, and the qualitative and quantitative analysis of the raw gas CO ₂ and H ₂ and the product ethanol and propanol are carried out respectively.

Example 29

This example provides a specific implementation of the nitrogen-doped tungsten carbide catalyst containing copper additives described in Example 9 for hydrogenation of carbon dioxide to alcohol, including the following steps:

The nitrogen-doped tungsten carbide catalyst containing copper additives is granulated to 70 mesh, and placed in a fixed-bed reactor with an inner diameter of 10mm. The raw material gas for the catalytic reaction is CO2 _{and H2} Mixed gas, the volume ratio is 1:3.8, the reaction temperature of the catalytic reaction is 280°C; the reaction pressure of the catalytic reaction is 5.2MPa; the volume space velocity of the catalytic reaction is 2500h ^-1 ;

The outlet pipeline of the reactor is passed through two gas chromatographs in the 100°C insulation tube, and the qualitative and quantitative analysis of the raw gas CO ₂ and H ₂ and the product ethanol and propanol are carried out respectively.

Example 30

This example provides a specific implementation of the nitrogen-doped tungsten carbide catalyst containing iron promoter described in Example 12 for hydrogenation of carbon dioxide to alcohol, including the following steps:

The nitrogen-doped tungsten carbide catalyst containing iron additives is granulated to 70 meshes, and placed in a fixed-bed reactor with an inner diameter of 10mm. The raw gas for the catalytic reaction is CO2 _{and H2} Mixed gas, the volume ratio is 1:3.8, the reaction temperature of the catalytic reaction is 260°C; the reaction pressure of the catalytic reaction is 3.8MPa; the volume space velocity of the catalytic reaction is 5400h ^-1 ;

The outlet pipeline of the reactor is passed through two gas chromatographs in the 100°C insulation tube, and the qualitative and quantitative analysis of the raw gas CO ₂ and H ₂ and the product ethanol and propanol are carried out respectively.

Test example 1

Example 13-30 Reactor outlet pipeline leads into two gas chromatographs, gas chromatograph 1 adopts FID detector, is used for quantitatively analyzing ethanol, propanol product in the product, gas chromatograph 2 adopts TCD detector, is used for quantitatively analyzing mixed The conversion rate of CO2 in the gas, the calculation method is shown in the following formula, and the measured results are shown in Table 1:

Table 1. _CO Hydroconversion reaction performance comparison in Examples 13-302

Result discussion: the nitrogen-doped tungsten carbide catalyst provided by the present invention can significantly improve the conversion rate of carbon dioxide and the selectivity of ethanol, and the tungsten content in the catalyst precursor, nitrogen content, _H Volume fraction, heating rate and carbonization temperature and The space velocity, reaction temperature, pressure, and feed gas ratio in the catalytic reaction will all affect the conversion of CO ₂ and the selectivity of ethanol and propanol.

Apparently, the above-mentioned embodiments are only examples for clearly illustrating, rather than limiting the implementation. For those of ordinary skill in the art, other changes or changes in different forms can be made on the basis of the above description. It is not necessary and impossible to exhaustively list all the implementation manners here. However, the obvious changes or changes derived therefrom are still within the scope of protection of the present invention.

Claims (13)

1. The preparation method of the nitrogen-doped tungsten carbide catalyst is characterized by comprising the following steps of:

(1) Preparing a mixed solution of soluble tungsten salt, methylene amine organic matters and water, soaking the mixed solution on a carrier containing an acid site B, and drying at 80-120 ℃ to obtain a catalyst precursor;

(2) Placing the precursor in a mixed atmosphere containing hydrogen, and carrying out temperature programming on the precursor to 600-900 ℃ for carbonization for 2-12h to obtain a supported nitrogen-doped tungsten carbide catalyst, wherein the temperature programming rate is 0.5-2 ℃/min;

the nitrogen-doped tungsten carbide catalyst comprises a carrier and a nitrogen-doped tungsten carbide active ingredient loaded on the carrier, wherein the carrier contains a B acid site, and the nitrogen-doped tungsten carbide active ingredient is nitrogen-doped tungsten carbide nano-particles with the particle size of less than or equal to 10nm.

2. The production method according to claim 1, wherein the molar ratio of the soluble tungsten salt to the methylene amine is 1.

3. The preparation method of claim 1, wherein the nitrogen-doped tungsten carbide catalyst contains 5wt% to 50wt% of tungsten and 0.5wt% to 5wt% of nitrogen.

4. The method of claim 1, wherein the soluble tungsten salt comprises one of ammonium metatungstate, ammonium paratungstate, sodium tungstate, and phosphotungstic acid.

5. The method of claim 1, wherein the organic methylene amine is one of hexamethylenediamine, hexamethylenetetramine, tetramethylenediamine, and trimethylhexamethylenediamine.

6. The method of claim 1, wherein the B acid site carrier comprises a molecular sieve carrier containing B acid sites, including one of ZSM-5 type carrier, Y type carrier, beta type carrier and MOR type carrier.

7. The preparation method of claim 1, wherein the nitrogen-doped tungsten carbide catalyst further comprises an auxiliary agent, wherein the auxiliary agent comprises at least one of Cu, co, in and Fe, and the content of the auxiliary agent is 0.5wt% to 5wt%.

8. The method of claim 1, wherein the gas mixture further comprises at least one of nitrogen, argon and helium, and the volume fraction of the hydrogen gas is 10-50%.

9. Use of the nitrogen-doped tungsten carbide catalyst prepared by the method of any one of claims 1 to 8 in the production of alcohol from carbon dioxide with hydrogen.

10. A method for preparing alcohol by catalyzing carbon dioxide hydrogenation gas is characterized in that the volume ratio of CO is 1 ₂ And H ₂ Reacting under the action of a catalyst to generate alcohol, whereinThe catalyst is a nitrogen-doped tungsten carbide catalyst prepared by the method for preparing a nitrogen-doped tungsten carbide catalyst according to any one of claims 1 to 8.

11. The method for producing alcohol from carbon dioxide and hydrogen gas according to claim 10, wherein the reaction temperature of the catalytic reaction is 200-350 ℃.

12. The method for producing alcohol from carbon dioxide and hydrogen gas according to claim 10 or 11, wherein the reaction pressure of the catalytic reaction is 0.5 to 10MPa.

13. The method for preparing alcohol from carbon dioxide hydrogenation gas according to claim 10, wherein the volume space velocity of the catalytic reaction is 1000-10000h ^-1 。

Images