CN116135306A - A kind of high-performance alkali metal modified CuFeZr catalytic material and preparation method thereof - Google Patents

Abstract

The invention belongs to the technical field of catalytic materials, in particular to a high-performance alkali metal-modified CuFeZr catalytic material and a preparation method thereof, comprising the following steps: S1, in the presence of a solvent, a zirconium salt and propylene oxide undergo a first contact reaction to obtain a solution I ; S2, the solution I is placed in a high-temperature oven for hydrothermal reaction to obtain an amorphous zirconia material; S3, in the presence of a solvent, the zirconia and copper salt are subjected to a second contact reaction to obtain a solution II; S4, the obtained The solution II and the precipitant are subjected to the third contact reaction, and after the reaction, the obtained substance is centrifuged, dried, pulverized, and calcined; S5, the obtained solid is subjected to the fourth contact reaction with the iron salt to obtain the solution III; S6, the obtained The solution III is subjected to the fifth contact reaction with the precipitant, and after the reaction, the obtained material is centrifuged, dried, and pulverized; S7, the obtained material is subjected to the sixth contact reaction with an alkali metal salt to obtain a product. It has the advantages of low cost, high catalytic activity and high thermal stability.

Description

A high-performance alkali metal-modified CuFeZr catalytic material and preparation method thereof

Technical Field

The invention belongs to the technical field of catalytic materials, and particularly relates to a high-performance alkali metal-modified CuFeZr catalytic material and a preparation method thereof.

Background Art

Oxide-based porous materials are good carriers in the field of catalysis, but the preparation method of high-performance low-carbon alcohol synthesis catalytic materials still needs further exploration. Copper-iron-based materials are widely used in catalytic reactions such as carbon dioxide hydrogenation to synthesize methanol and low-carbon alcohols, Fischer-Tropsch reaction, etc. due to their unique redox properties and high catalytic activity.

It is generally believed that the catalytic reaction mainly takes place on the copper surface and the Cu-Fe interface. However, copper-based catalysts are prone to become metallic copper due to their extremely unstable microstructure of active copper species in a reducing atmosphere. They are also prone to sintering at high temperatures, causing their exposed active area to decrease rapidly, resulting in a rapid decrease in catalytic activity or even inactivation.

Metals (such as copper, iron, etc.) highly dispersed in porous oxide materials with high surface areas have been proven to be good redox reaction catalysts. Copper oxide and iron oxide have relatively high thermal stability. At the same time, because they are active components or active additives for catalytic reactions such as synthesis gas and carbon dioxide hydrogenation to synthesize methanol and low-carbon alcohols, adding copper oxide, iron oxide and other metals to amorphous zirconium oxide with a high specific surface area can form nano-scale copper nanocrystals and rich alloy/interface species, thereby increasing the stability of active species and the ability of the catalyst to catalyze the dissociation of hydrogen and activate carbon dioxide, enhancing the yield and selectivity of low-carbon alcohols, and facilitating the hydrogenation reaction of carbon dioxide, thereby preparing a high-performance _CO2 hydrogenation to synthesize low-carbon alcohols catalytic material.

The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention and should not be regarded as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art.

Summary of the invention

In order to solve the above problems, the present invention provides a method for preparing a high-performance alkali metal-modified CuFeZr catalytic material, which has the advantages of low preparation cost, simple and safe operation, short reaction cycle, good product repeatability, etc.; the high-performance alkali metal-modified CuFeZr catalytic material prepared by the method has the advantages of low cost, high catalytic activity, high thermal stability, etc., can catalytically reduce _CO2 to synthesize low-carbon alcohols with high selectivity under relatively low temperature conditions, and can be used in the fields of material research and catalytic hydrogenation of carbon dioxide to synthesize low-carbon alcohols.

The present invention is achieved by adopting the following technical solutions:

The preparation method of high-performance alkali metal-modified CuFeZr catalyst material comprises the following steps:

S1, adding zirconium salt to ethanol solvent, dissolving by ultrasonication, and then adding propylene oxide to carry out a first contact reaction to obtain solution I;

S2, subjecting solution I to a hydrothermal reaction, and drying and crushing the resulting material to obtain amorphous zirconium oxide;

S3, adding amorphous zirconium oxide into water, ultrasonically dispersing, adding metal copper salt, and performing a second contact reaction to obtain solution II;

S4, adding a precipitant aqueous solution to solution II to carry out a third contact reaction, and after the reaction is completed, the obtained material is centrifuged, dried, crushed, and calcined;

S5, subjecting the obtained solid to a fourth contact reaction with a metal iron salt to obtain a solution III;

S6, subjecting the solution III to a fifth contact reaction with a precipitant, and after the reaction is completed, centrifuging, drying, and crushing the obtained material;

S7, the obtained material is subjected to a sixth contact reaction with an alkali metal salt, and after rotary evaporation of water, the obtained material is crushed and calcined to obtain a high-performance alkali metal-modified CuFeZr catalytic material.

In a preferred embodiment, in step S1, the ultrasonic dissolution is performed at a frequency of 40-60 KHz for 25-40 min; in a further preferred embodiment, the ultrasonic dissolution is performed at a frequency of 50 KHz for 30 min;

In a preferred embodiment, in step S1, the zirconium salt may be one of zirconium nitrate, zirconium oxychloride, zirconium chloride and zirconium sulfate; the molar ratio of propylene oxide and zirconium salt calculated as Zr element is (1.5-2.5):1; in a further preferred embodiment, the molar ratio of propylene oxide, ethanol and zirconium nitrate calculated as Zr element is (1.5-2.5):(60-70):1.

In a preferred embodiment, in step S1, the conditions of the first contact reaction are: temperature of 10-40° C. and time of 0.05-1 h.

In a preferred embodiment, in step S1, the first contact reaction is carried out under stirring conditions at a stirring rate of 50-500 rpm; in a further preferred embodiment, the first contact reaction is carried out under stirring conditions at a stirring rate of 350-450 rpm.

Preferably, in step S2, the temperature of the hydrothermal reaction is 100-200°C and the time is 15-25h.

In a preferred embodiment, in step S3, the conditions of the second contact reaction are: temperature of 10-40° C. and time of 0.05-10 h.

The copper salt may be any one of copper nitrate, copper sulfate, copper acetate and copper chloride;

In terms of mass ratio, the usage ratio of the metal copper salt in terms of Cu element and the amorphous zirconium oxide in terms of zirconium oxide is (0.2-0.3):1;

In a preferred embodiment, in step S3, the second contact reaction is carried out under stirring conditions at a stirring rate of 50-500 rpm; in a further preferred embodiment, the second contact reaction is carried out under stirring conditions at a stirring rate of 350-450 rpm.

In a preferred embodiment, in step S4, the conditions of the third contact reaction are: temperature of 70-90° C. and time of 0.1-10 h.

The precipitant can be any one of ammonium carbonate, ammonium bicarbonate, potassium carbonate, potassium bicarbonate, sodium carbonate, sodium bicarbonate, sodium hydroxide, potassium hydroxide, and ammonia water;

In terms of molar ratio, the ratio of the precipitant to the metal copper salt in terms of Cu element is 1-3:1;

In a preferred embodiment, in step S5, the conditions of the fourth contact reaction are: temperature of 10-40° C. and time of 0.1-10 h.

The iron salt may be any one of ferric nitrate, ferric acetate, ferric sulfate, and ferric chloride;

The mass ratio of the metal iron salt calculated as Fe element to the copper zirconium material calculated as copper zirconium oxide is (0.1-0.2):1;

In a preferred embodiment, in step S6, the fifth contact reaction is carried out under stirring conditions at a stirring rate of 50-500 rpm; in a further preferred embodiment, the fifth contact reaction is carried out under stirring conditions at a stirring rate of 350-450 rpm.

In a preferred embodiment, in step S6, the conditions of the fifth contact reaction are: temperature of 70-90° C. and time of 0.1-10 h.

The precipitant can be any one of ammonium carbonate, ammonium bicarbonate, potassium carbonate, potassium bicarbonate, sodium carbonate, sodium bicarbonate, sodium hydroxide, potassium hydroxide, and ammonia water;

In terms of molar ratio, the ratio of the precipitant to the metal iron salt in terms of Fe element is 1-3:1;

In a preferred embodiment, in step S7, the conditions of the sixth contact reaction are: temperature of 10-40° C. and time of 0.1-10 h.

The alkali metal salt may be any one of potassium carbonate, sodium carbonate, and cesium carbonate;

The molar ratio of the alkali metal salt calculated as the alkali metal element to the amorphous zirconium oxide calculated as the Zr element is (0.1-0.25):1;

In a preferred embodiment, in step S7, the sixth contact reaction is carried out under stirring conditions at a stirring rate of 50-500 rpm; in a further preferred embodiment, the sixth contact reaction is carried out under stirring conditions at a stirring rate of 350-450 rpm.

In a preferred embodiment, in steps S2 and S6, the drying conditions are as follows: the temperature is 40-80°C and the time is 2-24h;

Preferably, in step S4, the drying conditions include: temperature of 40-80°C, time of 2-24h; the calcination conditions include: temperature of 300-500°C, time of 0.5-8h.

Preferably, in step S7, the conditions for the rotary evaporation include: a temperature of 40-80°C, a vacuum degree of -0.08 to -0.1, and a time of 2-6 hours; and the conditions for the calcination include: a temperature of 300-500°C and a time of 3-10 hours.

The beneficial effects of the present invention are:

1. The preparation method of the present invention has the advantages of low preparation cost, simple and safe operation, short reaction cycle, good product reproducibility, etc.

2. The high-performance alkali metal-modified CuFeZr catalytic material prepared by the preparation method of the present invention can provide nano-scale copper/iron oxide nanocrystals, or copper-iron alloy/interface species, which can increase the stability of active species, the catalyst's catalytic hydrogen dissociation activity and the ability to activate carbon dioxide, and is beneficial to the selective catalytic carbon dioxide reduction reaction.

3. The high-performance alkali metal-modified CuFeZr catalytic material prepared by the preparation method of the present invention has the advantages of low cost, high catalytic activity, high thermal stability, etc. It can catalyze the reduction of _CO2 to synthesize low-carbon alcohols with high selectivity under low temperature conditions, and can be used in the fields of material research and catalytic hydrogenation of carbon dioxide to synthesize low-carbon alcohols.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

FIG. 1 is an XRD spectrum of the CuFeZr catalytic material prepared in Example 1 of the present invention and the high-performance alkali metal-modified CuFeZr catalytic materials prepared in Examples 2-6.

DETAILED DESCRIPTION

The technical scheme in the embodiment will be described clearly and completely below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is only a part of the embodiment of the present invention, not all of the embodiments. Based on the embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

Example 1

A method for preparing a CuFeZr catalyst material comprises the following steps:

S1, at 25° C., 5.999 g of zirconium nitrate pentahydrate was dissolved in ethanol to obtain a mixture, and after ultrasonic dissolution at a frequency of 50 KHz for 30 min, propylene oxide was added to carry out a first contact reaction for 2 min to obtain a solution I;

S2, performing a hydrothermal reaction at 150°C for 20 hours, drying the obtained solid sol at 60°C for 24 hours, and then drying at 200°C for 3 hours before crushing to obtain a powdery amorphous zirconium oxide solid; in terms of molar ratio, the amount of zirconium nitrate pentahydrate: ethanol: propylene oxide is 1:60:1.5;

S3, at 25°C, 0.3 g of amorphous zirconium oxide solid is dispersed in 50 mL of water under ultrasonic conditions at a frequency of 50 KHz for 15 min to obtain a zirconium oxide aqueous dispersion with a mass concentration of 6 g/L; the water is deionized water;

S4, at 25°C, potassium carbonate is dissolved in water to form a potassium carbonate aqueous solution with a mass concentration of 9.6 g/L;

S5, taking the zirconium oxide aqueous dispersion, adding 0.2215 g of copper nitrate, stirring at 400 rpm for a second contact reaction at 25° C. for 1 hour; the molar ratio of potassium carbonate to copper nitrate in terms of Cu is 1.5:1;

S6, adding the potassium carbonate aqueous solution at 80°C and stirring for a third contact reaction for 3 hours; after the reaction is completed, the obtained material is fully washed and centrifuged at 6000-8000 rpm, the precipitate obtained after centrifugation is dried at 60°C for 12 hours and then crushed, and calcined at 400°C in a muffle furnace in an air atmosphere for 4 hours to obtain a 25Cu/a-ZrOx material;

S7, at 25°C, take 0.5g of the above 25Cu/a-ZrOx material, disperse it in 50mL of water under ultrasonic conditions at a frequency of 50KHz for 15min to obtain a copper-zirconium composite oxide aqueous dispersion with a mass concentration of 10g/L; at 25°C, dissolve ammonium bicarbonate in water to form an ammonium bicarbonate aqueous solution with a mass concentration of 9.6g/L; the water is deionized water;

S8, taking the zirconium oxide aqueous dispersion, adding 0.537 g of ferric sulfate, stirring at 25° C. and 400 rpm for a fourth contact reaction for 1 hour; the molar ratio of the ammonium bicarbonate to the ferric sulfate calculated as Fe is 2:1;

S9, adding the aqueous solution of ammonium bicarbonate at 80° C. and stirring for the fifth contact reaction for 3 hours; after the reaction is completed, the obtained material is fully washed and centrifuged at 6000-8000 rpm, and the precipitate obtained after centrifugation is dried at 60° C. for 12 hours and then crushed; calcining at 400° C. in a muffle furnace in an air atmosphere for 4 hours to obtain a brown-black 15Fe/25Cu/a-ZrO _x catalytic material.

Example 2

A method for preparing a high-performance alkali metal-modified CuFeZr catalyst material comprises the following steps:

S1, at 25° C., 4.5036 g of zirconium oxychloride octahydrate was dissolved in ethanol to obtain a mixture, and after ultrasonic dissolution at a frequency of 40 KHz for 45 min, propylene oxide was added to carry out a first contact reaction for 10 min to obtain a solution I;

S2, performing a hydrothermal reaction at 150°C for 24 hours, drying the obtained solid sol at 60°C for 28 hours, and then drying at 200°C for 6 hours before crushing to obtain a powdery amorphous zirconium oxide solid; in terms of molar ratio, the amount of zirconium oxychloride: ethanol: propylene oxide is 1:70:2.5;

S3, at 25°C, 0.3 g of amorphous zirconium oxide solid is dispersed in 50 mL of water under ultrasonic conditions at a frequency of 45 KHz for 15 min to obtain a zirconium oxide aqueous dispersion with a mass concentration of 6 g/L; the water is deionized water;

S4, at 25°C, dissolving sodium carbonate in water to form a sodium carbonate aqueous solution with a mass concentration of 9.6 g/L;

S5, taking the zirconium oxide aqueous dispersion, adding 0.2949 g of copper sulfate pentahydrate, stirring at 25° C. and 350 rpm for a second contact reaction for 1.5 hours; the molar ratio of the sodium carbonate to the copper sulfate pentahydrate calculated as Cu is 2.5:1;

S6, adding the sodium carbonate aqueous solution at 80° C. and stirring for a third contact reaction for 5 hours; after the reaction is completed, the obtained material is fully washed and centrifuged at 6000-8000 rpm, the precipitate obtained after centrifugation is dried at 60° C. for 12 hours, crushed, and calcined at 400° C. in a muffle furnace in an air atmosphere for 4 hours to obtain a 25Cu/a-ZrOx material;

S7, at 25°C, take 0.5g of the above 25Cu/a-ZrOx material, disperse it in 50mL of water under ultrasonic conditions at a frequency of 50KHz for 15min to obtain a copper-zirconium composite oxide aqueous dispersion with a mass concentration of 10g/L; at 25°C, dissolve sodium bicarbonate in water to form a sodium bicarbonate aqueous solution with a mass concentration of 9.6g/L; the water is deionized water;

S8, taking the copper-zirconium composite oxide aqueous dispersion, adding 0.2086 g of ferric acetate, stirring at 25° C. and 400 rpm for a fourth contact reaction for 1 hour; the molar ratio of the sodium bicarbonate to the ferric acetate calculated as Fe is 3:1;

S9, adding the sodium bicarbonate aqueous solution at 80° C. and stirring for the fifth contact reaction for 3 hours; after the reaction is completed, the obtained material is fully washed and centrifuged at 6000-8000 rpm, and the precipitate obtained after centrifugation is dried at 60° C. for 12 hours and then crushed;

S10, add 24.7 mg of sodium carbonate and 1 mL of aqueous solution at 25° C., stir at 400 rpm for the sixth contact reaction at 25° C. for 2 h, then dry at 40-70° C. for 2-6 h in a rotary evaporator with a vacuum degree of -0.08 to -0.1, and calcine in a muffle furnace at 400° C. in an air atmosphere for 4 h to obtain a brown-black 3Na-10Fe/25Cu/a-ZrOx catalytic material.

Example 3

A method for preparing a high-performance alkali metal-modified CuFeZr catalyst material comprises the following steps:

S1, at 25°C, 3.2569 g of zirconium chloride was dissolved in ethanol to obtain a mixture, and after ultrasonic dissolution for 45 min at a frequency of 30 KHz, propylene oxide was added to carry out a first contact reaction for 8 min to obtain a solution I;

S2, performing a hydrothermal reaction at 150°C for 16 hours, drying the obtained solid sol at 60°C for 24 hours, and then drying at 200°C for 3 hours before crushing to obtain a powdery amorphous zirconium oxide solid; in terms of molar ratio, the amount of zirconium chloride: ethanol: propylene oxide is 1:65:2;

S3, at 25°C, 0.3 g of amorphous zirconium oxide solid is dispersed in 50 mL of water under ultrasonic conditions at a frequency of 45 KHz for 15 min to obtain a zirconium oxide aqueous dispersion with a mass concentration of 6 g/L; the water is deionized water;

S4, at 25°C, dissolving sodium bicarbonate in water to form a sodium bicarbonate aqueous solution with a mass concentration of 9.6 g/L;

S5, taking the zirconium oxide aqueous dispersion, adding 0.1588 g of copper chloride, stirring at 400 rpm for a second contact reaction at 25° C. for 1 hour; the molar ratio of the sodium bicarbonate to the copper chloride calculated as Cu is 2:1;

S6, adding the sodium bicarbonate aqueous solution at 80° C. and stirring for a third contact reaction for 5 hours; after the reaction is completed, the obtained material is fully washed and centrifuged at 6000-8000 rpm, the precipitate obtained after centrifugation is dried at 60° C. for 12 hours, crushed, and calcined at 400° C. in a muffle furnace in an air atmosphere for 4 hours to obtain a 25Cu/a-ZrOx material;

S7, at 25°C, take 0.5g of the above 25Cu/a-ZrOx material, disperse it in 50mL of water under ultrasonic conditions at a frequency of 50KHz for 15min to obtain a copper-zirconium composite oxide aqueous dispersion with a mass concentration of 10g/L; at 25°C, dissolve potassium hydroxide in water to form a potassium hydroxide aqueous solution with a mass concentration of 9.6g/L; the water is deionized water;

S8, taking the copper-zirconium composite oxide aqueous dispersion, adding 0.2182 g of ferric chloride, stirring at 25° C. and 400 rpm for a fourth contact reaction for 1 hour; the molar ratio of potassium hydroxide to ferric chloride calculated as Fe is 2.5:1;

S9, adding the potassium hydroxide aqueous solution at 80° C. and stirring for a fifth contact reaction for 3 hours; after the reaction is completed, the obtained material is fully washed and centrifuged at 6000-8000 rpm, and the precipitate obtained after centrifugation is dried at 60° C. for 12 hours and then crushed;

S10, add 32.2 mg potassium carbonate 1 mL aqueous solution at 25 ° C, stir at 400 rpm at 25 ° C for the sixth contact reaction for 2 hours, then dry at 40-70 ° C for 2-6 hours in a rotary evaporator with a vacuum degree of -0.08 to -0.1, and calcine in a muffle furnace at 400 ° C for 4 hours in an air atmosphere to obtain a brown-black 3K-15Fe/25Cu/a-ZrOx catalytic material.

Example 4

A method for preparing a high-performance alkali metal-modified CuFeZr catalyst material comprises the following steps:

S1, at 25°C, 3.96 g of zirconium sulfate was dissolved in ethanol to obtain a mixture, and after ultrasonic dissolution for 30 min at a frequency of 50 KHz, propylene oxide was added to carry out a first contact reaction for 6 min to obtain a solution I;

S2, performing a hydrothermal reaction at 150°C for 20 hours, drying the obtained solid sol at 60°C for 24 hours, and then drying at 200°C for 3 hours before crushing to obtain a powdery amorphous zirconium oxide solid; in terms of molar ratio, the amount of zirconium sulfate: ethanol: propylene oxide is 1:60:1.5;

S3, at 25°C, 0.3 g of amorphous zirconium oxide solid is dispersed in 50 mL of water under ultrasonic conditions at a frequency of 45 KHz for 15 min to obtain a zirconium oxide aqueous dispersion with a mass concentration of 6 g/L; the water is deionized water;

S4, at 25°C, dissolving sodium hydroxide in water to form a sodium hydroxide aqueous solution with a mass concentration of 9.6 g/L;

S5, taking the zirconium oxide aqueous dispersion, adding 0.2358 g of copper acetate monohydrate, stirring at 400 rpm for a second contact reaction at 25° C. for 1 hour; the molar ratio of the sodium hydroxide to the copper acetate monohydrate calculated as Cu is 3:1;

S6, adding the sodium hydroxide aqueous solution at 80° C. and stirring for a third contact reaction for 3 hours; after the reaction is completed, the obtained material is fully washed and centrifuged at 6000-8000 rpm, the precipitate obtained after centrifugation is dried at 60° C. for 12 hours, crushed, and calcined at 400° C. in a muffle furnace in an air atmosphere for 4 hours to obtain a 25Cu/a-ZrOx material;

S7, at 25°C, take 0.5g of the above 25Cu/a-ZrOx material, disperse it in 50mL of water under ultrasonic conditions of 50KHz for 15min to obtain a copper-zirconium composite oxide aqueous dispersion with a mass concentration of 10g/L; the water is deionized water;

S8, taking the copper-zirconium composite oxide aqueous dispersion, adding 0.7235 g of ferric nitrate nonahydrate, stirring at 25° C. and 400 rpm for a fourth contact reaction for 1 hour; the molar ratio of the ammonia water to the ferric nitrate nonahydrate calculated as Fe is 1:1;

S9, adding the ammonia solution at 80° C. and stirring for the fifth contact reaction for 3 hours; after the reaction is completed, the obtained material is fully washed and centrifuged at 6000-8000 rpm, and the precipitate obtained after centrifugation is dried at 60° C. for 12 hours and then crushed;

S10, add 75.9 mg of cesium carbonate and 1 mL of aqueous solution at 25°C, stir at 400 rpm for the sixth contact reaction at 25°C for 2 hours, then dry at 40-70°C for 2-6 hours in a rotary evaporator with a vacuum degree of -0.08 to -0.1, and calcine in a muffle furnace at 400°C in an air atmosphere for 4 hours to obtain a brown-black 3Cs-20Fe/25Cu/a-ZrOx catalytic material.

Example 5

A method for preparing a high-performance alkali metal-modified CuFeZr catalyst material comprises the following steps:

S1, at 25° C., 5.999 g of zirconium nitrate pentahydrate was dissolved in ethanol to obtain a mixture, and after ultrasonic dissolution for 30 min at a frequency of 50 KHz, propylene oxide was added to carry out a first contact reaction for 4 min to obtain a solution I;

S2, performing a hydrothermal reaction at 150°C for 20 hours, drying the obtained solid sol at 60°C for 24 hours, and then drying at 200°C for 3 hours before crushing to obtain a powdery amorphous zirconium oxide solid; in terms of molar ratio, the amount of zirconium nitrate pentahydrate: ethanol: propylene oxide is 1:60:1.5;

S3, at 25°C, 0.3 g of amorphous zirconium oxide solid is dispersed in 50 mL of water under ultrasonic conditions at a frequency of 45 KHz for 15 min to obtain a zirconium oxide aqueous dispersion with a mass concentration of 6 g/L; the water is deionized water;

S4, at 25°C, dissolving ammonium carbonate in water to form an ammonium carbonate aqueous solution with a mass concentration of 9.6 g/L;

S5, taking the zirconium oxide aqueous dispersion, adding 0.2358 g of copper acetate monohydrate, stirring at 400 rpm for a second contact reaction at 25° C. for 1 hour; the molar ratio of the ammonium carbonate to the copper acetate monohydrate calculated as Cu is 1:1;

S6, adding the aqueous ammonium carbonate solution at 80°C and stirring for a third contact reaction for 3 hours; after the reaction is completed, the obtained material is fully washed and centrifuged at 6000-8000 rpm, the precipitate obtained after centrifugation is dried at 60°C for 12 hours, crushed, and calcined at 400°C in a muffle furnace in an air atmosphere for 4 hours to obtain a 25Cu/a-ZrOx material;

S7, at 25°C, take 0.5g of the above 25Cu/a-ZrOx material, disperse it in 50mL of water under ultrasonic conditions of 50KHz for 15min to obtain a copper-zirconium composite oxide aqueous dispersion with a mass concentration of 10g/L; the water is deionized water;

S8, taking the copper-zirconium composite oxide aqueous dispersion, adding 0.5426 g of ferric nitrate nonahydrate, stirring at 25° C. and 400 rpm for a fourth contact reaction for 1 hour; the molar ratio of the ammonium carbonate to the ferric nitrate nonahydrate calculated as Fe is 2:1;

S9, adding the aqueous ammonium carbonate solution at 80° C. and stirring for a fifth contact reaction for 3 hours; after the reaction is completed, the obtained material is fully washed and centrifuged at 6000-8000 rpm, and the precipitate obtained after centrifugation is dried at 60° C. for 12 hours and then crushed;

S10, add 42.9 mg potassium carbonate and 1 mL aqueous solution at 25° C., stir at 400 rpm for the sixth contact reaction at 25° C. for 2 h, then dry at 40-70° C. for 2-6 h in a rotary evaporator with a vacuum degree of -0.08 to -0.1, and calcine in a muffle furnace in an air atmosphere at 400° C. for 4 h to obtain a brown-black 4K-15Fe/25Cu/a-ZrOx catalytic material.

Example 6

A method for preparing a high-performance alkali metal-modified CuFeZr catalyst material comprises the following steps:

S1, at 25° C., 5.999 g of zirconium nitrate pentahydrate was dissolved in ethanol to obtain a mixture, and after ultrasonic dissolution at a frequency of 50 KHz for 30 min, propylene oxide was added to carry out a first contact reaction for 2 min to obtain a solution I;

S2, performing a hydrothermal reaction at 150°C for 20 hours, drying the obtained solid sol at 60°C for 24 hours, and then drying at 200°C for 3 hours before crushing to obtain a powdery amorphous zirconium oxide solid; in terms of molar ratio, the amount of zirconium nitrate pentahydrate: ethanol: propylene oxide is 1:60:1.5;

S3, at 25°C, 0.3 g of amorphous zirconium oxide solid is dispersed in 50 mL of water under ultrasonic conditions at a frequency of 45 KHz for 15 min to obtain a zirconium oxide aqueous dispersion with a mass concentration of 6 g/L; the water is deionized water;

S4, at 25°C, dissolving ammonium carbonate in water to form an ammonium carbonate aqueous solution with a mass concentration of 9.6 g/L;

S5, taking the zirconium oxide aqueous dispersion, adding 0.2358 g of copper acetate monohydrate, stirring at 400 rpm for a second contact reaction at 25° C. for 1 hour; the molar ratio of ammonium carbonate to copper acetate monohydrate in terms of Cu is 1.5:1;

S6, adding the aqueous ammonium carbonate solution at 80°C and stirring for a third contact reaction for 3 hours; after the reaction is completed, the obtained material is fully washed and centrifuged at 6000-8000 rpm, the precipitate obtained after centrifugation is dried at 60°C for 12 hours, crushed, and calcined at 400°C in a muffle furnace in an air atmosphere for 4 hours to obtain a 25Cu/a-ZrOx material;

S7, at 25°C, take 0.5g of the above 25Cu/a-ZrOx material, disperse it in 50mL of water under ultrasonic conditions of 50KHz for 15min to obtain a copper-zirconium composite oxide aqueous dispersion with a mass concentration of 10g/L; the water is deionized water;

S8, taking the copper-zirconium composite oxide aqueous dispersion, adding 0.5426 g of ferric nitrate nonahydrate, stirring at 25° C. and 400 rpm for a fourth contact reaction for 1 hour; the molar ratio of the ammonium carbonate to the ferric nitrate nonahydrate calculated as Fe is 2.5:1;

S9, adding the aqueous ammonium carbonate solution at 80° C. and stirring for a fifth contact reaction for 3 hours; after the reaction is completed, the obtained material is fully washed and centrifuged at 6000-8000 rpm, and the precipitate obtained after centrifugation is dried at 60° C. for 12 hours and then crushed;

S10, add 53.7 mg potassium carbonate and 1 mL aqueous solution at 25°C, stir at 400 rpm for the sixth contact reaction at 25°C for 2 hours, then dry at 40-70°C for 2-6 hours in a rotary evaporator with a vacuum degree of -0.08 to -0.1, and calcine in a muffle furnace at 400°C in an air atmosphere for 4 hours to obtain a brown-black 5K-15Fe/25Cu/a-ZrOx catalytic material.

Example 7

A method for preparing a high-performance alkali metal-modified CuFeZr catalyst material comprises the following steps:

S1, at 25° C., 5.999 g of zirconium nitrate pentahydrate was dissolved in ethanol to obtain a mixture, and after ultrasonic dissolution at a frequency of 50 KHz for 30 min, propylene oxide was added to carry out a first contact reaction for 2 min to obtain a solution I;

S2, performing a hydrothermal reaction at 150°C for 20 hours, drying the obtained solid sol at 60°C for 24 hours, and then drying at 200°C for 3 hours before crushing to obtain a powdery amorphous zirconium oxide solid; in terms of molar ratio, the amount of zirconium nitrate pentahydrate: ethanol: propylene oxide is 1:60:1.5;

S3, at 25°C, 0.3 g of amorphous zirconium oxide solid is dispersed in 50 mL of water under ultrasonic conditions at a frequency of 45 KHz for 15 min to obtain a zirconium oxide aqueous dispersion with a mass concentration of 6 g/L; the water is deionized water;

S4, at 25°C, dissolving ammonium carbonate in water to form an ammonium carbonate aqueous solution with a mass concentration of 9.6 g/L;

S5, taking the zirconium oxide aqueous dispersion, adding 0.1886 g of copper acetate monohydrate, stirring at 400 rpm for a second contact reaction at 25° C. for 1 hour; the molar ratio of the ammonium carbonate to the copper acetate monohydrate calculated as Cu is 1.5:1;

S6, adding the aqueous solution of ammonium carbonate at 80°C, stirring for a third contact reaction for 3 hours; after the reaction is completed, the obtained material is fully washed and centrifuged at 6000-8000 rpm, the precipitate obtained after centrifugation is dried at 60°C for 12 hours, crushed, and calcined at 400°C in a muffle furnace in an air atmosphere for 4 hours to obtain a 20Cu/a-ZrOx material;

S7, at 25°C, take 0.5g of the above 20Cu/a-ZrOx material, disperse it in 50mL of water under ultrasonic conditions of 50KHz for 15min to obtain a copper-zirconium composite oxide aqueous dispersion with a mass concentration of 10g/L; the water is deionized water;

S8, taking the copper-zirconium composite oxide aqueous dispersion, adding 0.5426 g of ferric nitrate nonahydrate, stirring at 25° C. and 400 rpm for a fourth contact reaction for 1 hour; the molar ratio of the ammonium carbonate to the ferric nitrate nonahydrate calculated as Fe is 1.5:1;

S9, adding the aqueous ammonium carbonate solution at 80° C. and stirring for a fifth contact reaction for 3 hours; after the reaction is completed, the obtained material is fully washed and centrifuged at 6000-8000 rpm, and the precipitate obtained after centrifugation is dried at 60° C. for 12 hours and then crushed;

S10, add 32.2 mg potassium carbonate 1 mL aqueous solution at 25 ° C, stir at 400 rpm at 25 ° C for the sixth contact reaction for 2 hours, then dry at 40-70 ° C for 2-6 hours in a rotary evaporator with a vacuum degree of -0.08 to -0.1, and calcine in a muffle furnace at 400 ° C for 4 hours in an air atmosphere to obtain a brown-black 3K-15Fe/20Cu/a-ZrOx catalytic material.

Test Example 1

The catalysts of the above examples were tested to obtain specific surface area and pore size.

The specific surface area was obtained by testing with Micromeritics ASAP-2010; the pore size was obtained by testing with Micromeritics ASAP-2010.

The results are shown in Table 1.

Table 1 Test results of specific surface area of catalytic materials obtained in Examples 1 to 6

As can be seen from Table 1, the alkali metal modified CuFeZr catalytic material prepared by the present invention has a specific surface area of ^35-88m2 /g, which can effectively increase the stability of active metal/interface species, improve the ability of catalytic dissociation of hydrogen and activation of carbon dioxide, and is conducive to the reaction of hydrogenating carbon dioxide to produce low-carbon alcohols.

Test Example 2

The catalysts of the above examples were used to test the performance of catalytic hydrogenation of _CO2 gas to produce low-carbon alcohols, wherein a micro-fixed bed simulation reaction system was established with a flow rate of _CO2 + _H2 mixed gas of 36.0mL/min (4vol% _N2 , 24vol% _CO2 , 72vol% _H2 ) and a space velocity of 3000mL/( _gcat ·h). First, before the activity test, 0.4g of the sample was reduced in a 10vol% _H2 /Ar gas flow at 320°C for 1h, and then _CO2 + _H2 + _N2 mixed reactants were introduced and pressurized to 5MPa. Subsequently, the catalytic performance was evaluated at different target temperatures (280, 300 and 320°C). The obtained tail gas components such as CO, CO ₂ , methanol, C2-C5 low-carbon alcohols, C2-C8 olefins and C1-C8 alkanes were quantitatively analyzed online by gas chromatograph equipped with a thermal conductivity detector and a flame ionization detector to obtain the data in Tables 2, 3 and 4. In addition, after changing the mass ratio of Cu/Zr, the 3K-15Fe/20Cu/a-ZrOx catalyst also achieved a CO ₂ conversion rate of 30.9% and a low-carbon alcohol selectivity and yield of 21.6% and 46.1 mg.g _cat ^-1 h ^-1 at 320°C.

Table 2: Temperature is 280℃

Table 3: Temperature is 300℃

Table 4: Temperature is 320℃

It can be seen from the above results that the catalytic material of the present invention has excellent carbon dioxide conversion rate and low-carbon alcohol selectivity/yield, reflecting excellent catalytic performance for preparing low-carbon alcohols by hydrogenation of carbon dioxide.

Test Example 3

The products obtained in the above Examples 1-6 were subjected to X-ray powder diffraction (XRD) experiments using a Miniflex 600 XRD diffractometer manufactured by Rigaku. The results are shown in FIG1 .

As can be seen from Figure 1, after doping with copper, iron and alkali metal K, the amorphous structure of the catalyst carrier is still maintained, and the crystalline phase peak metals of metallic copper, iron, potassium and their oxides are not detected. This shows that amorphous zirconia with a high specific surface area is conducive to the high dispersion of active metals and the formation of tiny-sized copper, iron, potassium nanocrystals or their rich alloy interface species, which significantly improves the material's performance in catalytic hydrogenation of _CO2 to produce low-carbon alcohols.

The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims (14)

1. A preparation method of a high-performance alkali metal modified CuFeZr catalytic material is characterized by comprising the following steps of: the method comprises the following steps:

s1, adding zirconium salt into an ethanol solvent, ultrasonically dissolving, and then adding propylene oxide for a first contact reaction to obtain a solution I;

s2, carrying out hydrothermal reaction on the solution I, and drying and crushing the obtained substance to obtain amorphous zirconia;

s3, adding amorphous zirconia into water, performing ultrasonic dispersion, adding copper salt, and performing a second contact reaction to obtain a solution II;

s4, adding a precipitant aqueous solution into the solution II to carry out a third contact reaction, centrifuging, drying, crushing and calcining the obtained substance after the reaction is finished to obtain a copper-zirconium material;

s5, carrying out a fourth contact reaction on the obtained solid and ferric salt to obtain a solution III;

s6, carrying out a fifth contact reaction on the solution III and a precipitator, centrifuging, drying and crushing the obtained substance after the reaction is finished;

s7, carrying out a sixth contact reaction on the obtained material and alkali metal salt, carrying out rotary evaporation and drying on water, and then crushing and calcining the obtained material to obtain the high-performance alkali metal modified CuFeZr catalytic material.

2. The method for preparing the high-performance alkali metal modified CuFeZr catalytic material according to claim 1, wherein the method comprises the following steps: in the step S1, the zirconium salt may be one of zirconium nitrate, zirconyl chloride, zirconium chloride, and zirconium sulfate;

the usage amount of the propylene oxide and the zirconium salt calculated as Zr element is (1.5-2.5) in terms of the mole ratio: 1.

3. the method of preparing a high surface area amorphous zirconia catalytic material according to claim 1, wherein: the conditions of the first contact reaction are as follows: the temperature is 10-40 ℃ and the time is 0.05-1h;

preferably, the first contact reaction is carried out with stirring at a rate of 50-500rpm.

4. The method for preparing the high-performance alkali metal modified CuFeZr catalytic material according to claim 1, wherein the method comprises the following steps: in the step S1, the temperature of the hydrothermal reaction is 100-200 ℃ and the time is 15-25h.

5. The method for preparing the high-performance alkali metal modified CuFeZr catalytic material according to claim 1, wherein the method comprises the following steps: in step S3, the conditions of the second contact reaction are as follows: the temperature is 10-40 ℃ and the time is 0.05-10h;

the copper salt can be any one of copper nitrate, copper sulfate, copper acetate and copper chloride;

the ratio by mass of the metal copper salt in terms of Cu element to the amorphous zirconia in terms of zirconia is (0.2-0.3): 1, a step of;

the second contact reaction is carried out with stirring at a rate of 50-500rpm.

6. The method for preparing the high-performance alkali metal modified CuFeZr catalytic material according to claim 1, wherein the method comprises the following steps: in step S3, the conditions of the third contact reaction are as follows: the temperature is 70-90 ℃ and the time is 0.1-10h;

the precipitant can be any one of ammonium carbonate, ammonium bicarbonate, potassium carbonate, potassium bicarbonate, sodium carbonate, sodium bicarbonate, sodium hydroxide, potassium hydroxide and ammonia water;

the molar ratio of the precipitant to the metal copper salt calculated as Cu element is (1-3).

7. The method for preparing the high-performance alkali metal modified CuFeZr catalytic material according to claim 1, wherein the method comprises the following steps: in step S2, the drying conditions are as follows: the temperature is 60-100deg.C, and the time is 4-24h.

8. The method for preparing the high-performance alkali metal modified CuFeZr catalytic material according to claim 1, wherein the method comprises the following steps: in step S4, the drying conditions include: the temperature is 40-80 ℃ and the time is 4-24 hours; the conditions of the calcination include: the temperature is 300-500 ℃ and the time is 3-10h.

9. The method for preparing the high-performance alkali metal modified CuFeZr catalytic material according to claim 1, wherein the method comprises the following steps: in step S5, the conditions of the fourth contact reaction are as follows: the temperature is 10-40 ℃ and the time is 0.05-10h;

the ferric salt can be any one of ferric nitrate, ferric acetate, ferric sulfate and ferric chloride;

the dosage mass ratio of the metallic ferric salt to the copper zirconium material calculated by Fe element is (0.1-0.2): 1, a step of;

the fourth contact reaction is carried out with stirring at a rate of 50-500rpm.

10. The method for preparing the high-performance alkali metal modified CuFeZr catalytic material according to claim 1, wherein the method comprises the following steps: in step S6, the conditions of the fifth contact reaction are as follows: the temperature is 70-90 ℃ and the time is 0.1-10h;

the precipitant can be any one of ammonium carbonate, ammonium bicarbonate, potassium carbonate, potassium bicarbonate, sodium carbonate, sodium bicarbonate, sodium hydroxide, potassium hydroxide and ammonia water;

the molar ratio of the precipitant to the metal copper salt calculated as Fe element is (1-3).

11. The method for preparing the high-performance alkali metal modified CuFeZr catalytic material according to claim 1, wherein the method comprises the following steps: in step S6, the drying conditions include: the temperature is 40-80 ℃ and the time is 4-24h.

12. The method for preparing the high-performance alkali metal modified CuFeZr catalytic material according to claim 1, wherein the method comprises the following steps: in step S7, the conditions of the sixth contact reaction are: the temperature is 10-50 ℃ and the time is 2-10h;

the alkali metal salt can be any one of potassium carbonate, sodium carbonate and cesium carbonate;

the molar ratio of the alkali metal salt calculated as alkali metal element to the amorphous zirconia calculated as Zr element is (0.10 to 0.25): 1, a step of;

the sixth contact reaction is carried out with stirring at a rate of 50-500rpm.

13. The method for preparing the high-performance alkali metal modified CuFeZr catalytic material according to claim 1, wherein the method comprises the following steps: in step S7, the conditions of the rotary evaporation include: the temperature is 40-80 ℃, the vacuum degree is-0.08 to-0.1, and the time is 2-6h; the conditions of the calcination include: the temperature is 300-500 ℃ and the time is 3-10h.

14. A high-performance alkali metal modified CuFeZr catalytic material is characterized in that: prepared by a process as claimed in any one of claims 1 to 13.

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