CN113877605B

CN113877605B - Catalyst for low-temperature oxidation of CO and preparation method thereof

Info

Publication number: CN113877605B
Application number: CN202110178373.8A
Authority: CN
Inventors: 脱永笑; 冯翔; 曹建琳; 张晓倩; 孟营; 闫昊; 周鑫; 刘熠斌; 杨朝合; 陈德
Original assignee: China University of Petroleum East China
Current assignee: China University of Petroleum East China
Priority date: 2021-02-09
Filing date: 2021-02-09
Publication date: 2024-02-02
Anticipated expiration: 2041-02-09
Also published as: CN113877605A

Abstract

The catalyst comprises Pt element as an active component, transition metal element M2 oxide and alkali metal element M1, wherein M2 is one or more of Mn, mo, fe, ni elements, M1 is alkali metal element, the Pt element accounts for 0.1-2wt% of the total mass of the catalyst, and the M1 element accounts for 1-10wt% of the total mass of the catalyst. First by M1OH or M1 ₂ CO ₃ The Pt/M1-M2 catalyst is prepared by preparing a basic mixture of Pt-M1-M2 by a coprecipitation method for a precipitant and then performing high-temperature treatment. The catalyst has higher CO catalytic oxidation activity and stability in various characteristic atmospheres (such as hydrogen-rich, carbon dioxide-rich and sulfur-containing) and has good application potential in CO elimination scenes such as fuel cells, automobile tail gas, low-temperature methanol washing tail gas and the like.

Description

Catalyst for low-temperature oxidation of CO and preparation method thereof

Technical Field

The invention relates to a catalyst for CO oxidation, in particular to a catalyst for CO oxidation in various characteristic atmospheres (such as hydrogen-rich, carbon dioxide-rich and sulfur-containing).

Background

CO is one of main atmospheric pollution gases, is extremely easy to combine with hemoglobin of a human body and is not easy to separate, so that organism tissues are anoxic and even the human body is choked to die, and when the concentration of CO in the air reaches 650ppm, poisoning symptoms of a male human body can occur within 1 hour. Meanwhile, in the petrochemical industry, catalysts used in many chemical processes have extremely high sensitivity to CO, and trace amounts of CO can poison or deactivate the catalysts. Therefore, effective elimination of CO has important applications in various fields, such as automobile exhaust gas purification, elimination of CO in industrial exhaust gas, and purification of hydrogen for fuel cells.

The CO catalytic oxidation is an effective method for eliminating CO, and has the advantages of simple process, economy, high efficiency and the like. However, in practical applications, the reaction gas generally contains a plurality of other gases besides a small amount of CO, and the gas types are different according to application scenes, and these gases may seriously affect the CO catalytic oxidation performance of the catalyst. For example, in proton exchange membrane fuel cells for CO removal in hydrogen rich atmospheres, H is evolved during CO adsorption oxidation ₂ Will compete to adsorb on the surface of the catalyst and O ₂ The reaction occurs, resulting in a decrease in catalytic oxidation activity and selectivity of CO. In the low-temperature methanol washing tail gas CO removal and CO2 laser gas purification, the reaction gas is rich in CO ₂ Atmosphere, CO ₂ Carbonate species can be generated on the surface of the catalyst, so that active sites are blocked, CO oxidation reaction is prevented from being carried out, and the activity and stability of the catalyst are greatly influenced. In addition, the realization of efficient removal of CO at low temperatures can reduce energy loss and economic investment.

The present application has been made in view of the above-described problems.

Disclosure of Invention

It is an object of the present invention to provide a catalyst for CO oxidation which has high CO catalytic oxidation activity and stability in various characteristic atmospheres (e.g., hydrogen-rich, carbon dioxide-rich, or/and sulfur-containing).

It is another object of the present invention to provide a catalyst for CO oxidation that has high CO low temperature catalytic oxidation activity and stability in a variety of characteristic atmospheres (e.g., hydrogen-rich, and/or carbon dioxide-rich).

The invention also aims to provide a preparation method of the catalyst for CO oxidation, which is simple and the obtained catalyst has higher CO catalytic oxidation activity and stability.

To achieve the object of the present invention, a catalyst for CO oxidation comprises: the catalyst comprises Pt element as an active component, transition metal element M2 oxide and one or more of alkali metal elements M1 and M2 selected from Mn, mo, fe, ni, wherein M1 is an alkali metal element, the Pt element accounts for 0.1-2% of the total mass of the catalyst, and the M1 element accounts for 1-10% of the total mass of the catalyst.

The preparation method of the catalyst for CO oxidation comprises the steps of mixing Pt precursor solution and M2 precursor solution to obtain a mixture A, dripping the mixture A into a solution containing M1 element, adjusting pH=7-10 after dripping to obtain a mixture B, and crystallizing, washing and treating the mixture B at high temperature to obtain the catalyst.

The catalyst for CO oxidation in the present application preferentially oxidizes CO in various atmospheres (such as hydrogen-rich, carbon dioxide-rich, sulfur-containing) and exhibits excellent CO catalytic oxidation activity and stability. Therefore, the catalyst can be applied to CO elimination scenes such as fuel cells, automobile exhaust, low-temperature methanol washing exhaust and the like.

Drawings

FIG. 1 is a schematic diagram of the stability performance of a CO oxidation catalyst of the present application.

Detailed Description

The catalyst for CO oxidation of the present invention is described in further detail below. And do not limit the scope of the application, which is defined by the claims. Certain disclosed specific details provide a thorough understanding of the various disclosed embodiments. However, one skilled in the relevant art will recognize that embodiments can be practiced without one or more of the specific details, with other materials, etc.

In the description and in the claims, the terms "comprising," including, "and" containing "are to be construed as open-ended, meaning" including, but not limited to, unless the context requires otherwise.

Reference in the specification to "an embodiment," "one embodiment," "another embodiment," or "certain embodiments," etc., means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, it is not necessary for an "embodiment," "one embodiment," "another embodiment," or "certain embodiments" to refer to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. The various features disclosed in the specification may be replaced by alternative features serving the same, equivalent or similar purpose. Thus, unless expressly stated otherwise, the disclosed features are merely general examples of equivalent or similar features.

The invention will be further illustrated with reference to specific examples. It is to be understood that these examples are illustrative of the present invention and are not intended to limit the scope of the present invention. The experimental procedures, which do not address the specific conditions in the examples below, are generally carried out under conventional conditions or under conditions recommended by the manufacturer. All percentages, ratios, proportions, or parts are by weight unless otherwise indicated.

The units in weight volume percent are well known to those skilled in the art and refer, for example, to the weight of solute in 100 milliliters of solution.

In the present invention, the concentration unit "M" of the solution represents mol/L.

The term "crystallization" is the process by which a substance crystallizes in a chemical reaction.

The term "aging" is the natural standing that tends to stabilize the catalyst structure.

In the present application, the metal oxides in the catalyst are calculated as the oxide corresponding to the highest valence of the metal element.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. In addition, any methods and materials similar or equivalent to those described herein can be used in the methods of the present invention. The preferred methods and materials described herein are presented for illustrative purposes only.

The application mainly aims at the defect that the CO catalytic oxidation performance of the catalyst is seriously affected by the existence of other impurity gases in practical application (such as selectivity reduction, catalyst poisoning deactivation and the like) of CO catalytic oxidation, and provides a CO oxidation catalyst with high activity and stability in various characteristic atmospheres (such as hydrogen-rich atmosphere, carbon dioxide-rich atmosphere and sulfur-containing atmosphere) and a preparation method thereof.

In one aspect, a catalyst for the oxidation of CO comprises: the Pt element is taken as an active component, a transition metal element M2 oxide and an alkali metal element M1 or a plurality of elements M2 are selected from Mn, mo, fe, ni elements, M1 is selected from Na and/or K elements, and the Pt element accounts for 0.1-2wt% of the total mass of the catalyst.

The mass of the M1 element is 1-10wt% of the total mass of the catalyst; preferably, the mass of M1 is 2-5wt% of the total mass of the catalyst.

The residual amount in the catalyst is the content of substances containing various forms of the transition element M2.

In certain embodiments, M2 is selected from one or more of Mn, fe and Ni elements, and the mass of Pt element is 0.15-3% of the mass of M2 oxide.

In the CO oxidation catalyst, excessive alkali metal element is introduced to build efficient Pt inside the catalyst ⁺ —O(OH) _x -M1 and Pt ⁺ —O(OH) _x M2 synergistic interface which can optimize the adsorption capacity of CO on the active center and promote the activation of oxygen, thereby remarkably improving the catalytic oxidation performance of CO, and simultaneously promote H ₂ 、H ₂ And S and other oxidation products rapidly migrate to prevent the blockage and poisoning of Pt active centers. Thus, the catalyst shows excellent CO catalytic oxidation activity and stability in various characteristic atmospheres (such as hydrogen-rich, carbon dioxide-rich and sulfur-containing); in various characteristic gasesThe atmosphere (such as hydrogen-rich and carbon dioxide-rich) shows excellent CO low-temperature catalytic oxidation activity and stability. In particular, the mass of the M1 element is 1 to 10wt% of the total mass of the catalyst; preferably, the mass of M1 is 2-5wt% of the total mass of the catalyst, and the catalyst exhibits more excellent CO catalytic oxidation activity and stability in various characteristic atmospheres (e.g., hydrogen-rich, carbon dioxide-rich, sulfur-containing).

In certain embodiments, the transition metal element M2 is an Mn element.

Catalysts containing Mn, pt and alkali metal elements have excellent catalytic oxidation performance for CO in a complex atmosphere, particularly when sulfur is contained in a mixed gas to be treated, and also gases generally contained in industrial process gases (such as hydrogen sulfide).

The catalyst can be suitable for reaction processes such as adiabatic type, self-heating type, heat exchange type fixed bed and the like.

On the other hand, the catalyst for CO oxidation adopts a coprecipitation method.

In the present application, more alkali metal elements, in particular the mass of the M1 element, can be introduced into the CO oxidation catalyst, in particular by the CO-precipitation method, which is 1-10% by weight of the total mass of the catalyst; preferably, the mass of M1 is 2-5wt% of the total mass of the catalyst. Efficient Pt construction in catalyst internal structures ⁺ —O(OH) _x -M1 and Pt ⁺ —O(OH) _x The M2 synergistic interface, in turn, shows excellent CO catalytic oxidation activity and stability in various characteristic atmospheres (such as hydrogen-rich, carbon dioxide-rich, sulfur-containing); the catalyst shows excellent CO low-temperature catalytic oxidation activity and stability in hydrogen-rich and/or carbon dioxide-rich atmospheres.

The preparation method of the catalyst for CO oxidation comprises the steps of mixing a Pt precursor solution and an M2 precursor solution to obtain a mixed solution A, dripping the mixed solution A into a solution containing M1 element, adjusting pH=7-10 after dripping to obtain a mixture B, and crystallizing, washing and treating the mixture B at high temperature to obtain the catalyst.

In one embodiment, the Pt precursor is a water-soluble platinum element-containing salt solution. Preferably, chloroplatinic acid or platinum chloride is included.

The M2 precursor is water-soluble salt solution containing M2 element. Preferably nitrate or chloride containing M2 element.

The M1 element-containing solution comprises M1OH or M1 ₂ CO ₃ 。

In the present application, the transition metal M2 oxide or hydroxide is capable of forming a strong interaction with Pt, so that Pt exhibits high dispersibility, the introduction of an alkali metal enhances the stability of highly dispersed Pt, and the preparation method is relatively simple and easy to prepare on a large scale.

In one embodiment, the ratio of the amount of the substance of the M1 element in the solution of the M1 element to the sum of the amount of the substance of Pt in the Pt precursor solution and the amount of the substance of M2 in the M2 precursor solution is 2:1 to 4:1.

the mass of Pt element is 0.15-3% of the mass of M2 oxide.

In certain embodiments, the concentration of the Pt precursor may be 0.05M to 0.1M and the concentration of the M2 precursor is 0.5M to 1.5M.

The concentration of the M1 element-containing solution is 0.1M to 0.5M.

The concentration of each elemental precursor may be adjusted accordingly, depending on the amount of treatment in practice.

The solution for adjusting the pH of the solution is a dilute acid solution, such as dilute hydrochloric acid or dilute nitric acid.

The temperature of the mixture A and the solution containing M1 element is 50-90 ℃.

In certain embodiments, the drying step is performed prior to the high temperature treatment, with a drying temperature of less than 100 ℃.

In certain embodiments, the high temperature treatment is heating at a temperature of 150 to 400 ℃. The process of the high temperature treatment is carried out in an air atmosphere or in a mixed gas containing hydrogen.

Alternatively, the high temperature treatment is performed in an air atmosphere and then in a mixed gas containing hydrogen.

The hydrogen-containing mixed gas further includes an inert gas such as argon or helium.

In certain embodiments, the hydrogen is present in the hydrogen-containing gas mixture in an amount of about 10% by volume.

The mixed gas containing hydrogen is continuously introduced into the heating environment, and the flow rate is generally about 50mL/min.

The hydrogen content in the mixed gas and the flow rate of the mixed gas may be adjusted according to the amount of the catalyst to be specifically treated.

In the application, the high-temperature treatment can control the ratio of the valence Pt and the metal Pt by introducing air or/and mixed gas containing hydrogen at the temperature of 150-400 ℃. Thus, CO and H can be optimized ₂ 、CO ₂ 、H ₂ The adsorption energy of the gas such as S on the Pt active center realizes the preferential oxidation of CO in the atmosphere of mixing various impurities.

In certain embodiments, the high temperature treatment is heating at a temperature of 150 to 250 ℃.

Preferably, the temperature of the high temperature treatment is 150-400 ℃, and the time of the high temperature treatment is preferably 0.5-2h.

In some embodiments, the dried solid material is firstly heat-treated in an air atmosphere at a temperature ranging from 150 ℃ to 400 ℃, and then heat-treated in a hydrogen-containing mixed gas, so that the obtained catalyst has good oxidation catalytic performance on CO in hydrogen-rich, carbon dioxide-rich and other atmospheres, and the conversion rate of CO can reach more than 90% even up to 99% under the reaction condition of low temperature (even lower than 80 ℃).

Further, the preparation method of the catalyst for CO oxidation specifically comprises the following steps:

and dissolving a proper amount of Pt precursor solution in the M2 precursor solution, and uniformly stirring to obtain a mixed solution A.

Dripping the mixed solution A into M1OH or M1 at 50-90deg.C ₂ CO ₃ Adjusting the pH value to 7-10 after the dripping is finished, crystallizing at 50-90 ℃, and then standing at 50-90 ℃ to obtain a precipitate;

washing the precipitate until no chloride ions exist in the washing liquid, drying the washed precipitate in an oven, and finally carrying out high-temperature treatment at the temperature of 150-400 ℃ to obtain the catalyst.

In certain embodiments, the crystallization time is preferably 2h to 4h.

The standing aging time is preferably 1h to 5h.

The conditions for the high temperature treatment are as described above and will not be described in detail herein.

In yet another aspect, the CO oxidation catalyst described above is prepared by a CO-impregnation process.

A process for preparing the catalyst used for oxidizing CO includes such steps as mixing Pt precursor solution with M1 element-containing solution to obtain mixed solution B, immersing it on the oxide of M2, drying and high-temp treating.

The Pt precursor solution, the M1 element-containing solution, and the M2 oxide may be used in the co-impregnation method in the same type and amount as those of the co-precipitation method.

The drying and high temperature treatment can also adopt the process and process parameters of the coprecipitation method.

In a fourth aspect, the CO oxidation catalyst described above is applied to a honeycomb support. The specific method comprises the following steps:

mixing Pt precursor solution, M2 precursor solution and alumina powder to obtain mixed solution A1, mixing the solution containing M1 element with the mixed solution A1, regulating pH value to 7-10 to obtain mixture B1, crystallizing, washing and drying the mixture B1 to obtain catalyst powder,

mixing the obtained catalyst powder, a surfactant and water to prepare catalyst slurry, mixing a ceramic carrier with pore channels with the catalyst slurry to obtain a mixture C1, and treating the mixture C1 at high temperature to obtain the coated catalyst.

In certain embodiments, the surfactant is added in an amount of 0.5 to 8.0wt% based on the weight of the catalyst powder.

The drying temperature is lower than 100 ℃. Drying to a moisture content of the catalyst below 5wt%.

Preferably, the drying is performed at a drying temperature of 100 ℃ or less for 10 to 12 hours.

Surfactants include, but are not limited to, one or a mixture of several of polyethylene glycol, glycerol, polyacrylic acid, cellulose ether, stearic acid.

The mass ratio of the surfactant to the water is 1:10-1:80.

The ceramic carrier comprises cordierite honeycomb ceramics.

The coating on the ceramic support may be appropriately adjusted depending on the use environment. In the present application, the coating time is preferably 0.5h to 1.5h.

In certain embodiments, the mass of Pt element is 0.5-2% of the mass of alumina.

The types and amounts of the Pt precursor solution, the M2 precursor solution, and the M1 element solution may be referred to as the types and amounts of the respective substances by the above-described coprecipitation method.

The CO oxidation catalyst obtained by the method has the advantages that in the carbon dioxide-rich and/or hydrogen-rich atmosphere, the CO conversion rate reaches more than 90 percent below 150 ℃, and even the CO oxidation catalyst can achieve the effect at the low temperature below 100 ℃; the conversion rate of CO is more than 99% below 185 ℃, and even at a low temperature below 100 ℃, the effect can be achieved. In the atmosphere containing sulfur, the high-efficiency catalytic oxidation of CO can be realized, and the conversion rate can reach more than 99 percent.

The catalyst of the present invention and its catalytic effect are further described below in conjunction with specific examples. The substances used in the examples below are all chemically pure standard. The catalysts prepared in examples 1-6 below had M1 contents of between 2 and 5wt%.

Example 1

0.53mL of 0.07M chloroplatinic acid aqueous solution was dissolved in 14.0mL of 1M ferric chloride solution, and the mixture was stirred uniformly to obtain a mixed solution A. Under the water bath condition of 80 ℃, uniformly dripping the mixed solution A into 211.5mL of 0.2MKOH solution at the speed of 2mL/min, adjusting the pH to 8.5 by using 1M HCl after the dripping is finished, continuing to stir and crystallize for 3h in the water bath of 80 ℃, and then standing and aging for 1h in the water bath of 80 ℃.

And centrifugally washing the obtained precipitate until no chloride ions exist in the washing liquid, then placing the precipitate in an oven for drying at 80 ℃ for 12 hours, and finally, treating the precipitate in a hydrogen-argon mixed gas at 200 ℃ for 30 minutes to obtain the 0.5% Pt/K-Fe catalyst.

Example 2

0.53mL of 0.07M chloroplatinic acid aqueous solution was dissolved in 14.0mL of 1M ferric chloride solution, and the mixture was stirred uniformly to obtain a mixed solution A. Under the water bath condition of 80 ℃, uniformly dripping the mixed solution A into 212.3mL of 0.2M NaOH solution at the speed of 2mL/min, adjusting the pH to 8.5 by using 1M HCl after the dripping, continuing to stir and crystallize for 3h in the water bath of 80 ℃, and standing and aging for 1h in the water bath of 80 ℃.

And centrifugally washing the obtained precipitate until no chloride ions exist in the washing liquid, then placing the precipitate in an oven for drying at 80 ℃ for 12 hours, and finally, treating the precipitate in a hydrogen-argon mixed gas at 200 ℃ for 30 minutes to obtain the 0.5% Pt/Na-Fe catalyst.

Example 3

1.07mL of a 0.07M aqueous solution of chloroplatinic acid was dissolved in 14.0mL of a 1M solution of ferric nitrate, and the mixture was stirred uniformly to obtain a mixed solution A. Under the water bath condition of 80 ℃, uniformly dripping the mixed solution A) into 212.3mL of 0.2M NaOH solution at the speed of 2mL/min, adjusting the pH to 8.5 by using 1M HCl after the dripping is finished, continuing to stir and crystallize for 3h in the water bath of 80 ℃, and then standing and aging for 1h in the water bath of 80 ℃.

And centrifugally washing the obtained precipitate until no chloride ions exist in the washing liquid, then placing the precipitate in an oven for drying at 80 ℃ for 12 hours, and finally, treating the precipitate in a hydrogen-argon mixed gas at 200 ℃ for 30 minutes to obtain the 1% Pt/Na-Fe-1 catalyst.

Example 4

1.07mL of a 0.07M aqueous solution of chloroplatinic acid was dissolved in 14.0mL of a 1M solution of ferric nitrate, and the mixture was stirred uniformly to obtain a mixed solution A. Under the water bath condition of 80 ℃, uniformly dripping the mixed solution A into 212.3mL of 0.2M NaOH solution at the speed of 2mL/min, adjusting the pH to 8.5 by using 1M HCl after the dripping, continuing to stir and crystallize for 3h in the water bath of 80 ℃, and standing and aging for 1h in the water bath of 80 ℃.

And centrifugally washing the obtained precipitate until no chloride ions exist in the washing liquid, then placing the precipitate in an oven for drying at 80 ℃ for 12 hours, and finally, treating the precipitate in a hydrogen-argon mixed gas at 400 ℃ for 30 minutes to obtain the 1% Pt/Na-Fe-2 catalyst.

Example 5

And centrifugally washing the obtained precipitate until no chloride ions exist in the washing liquid, then placing the precipitate in an oven for drying at 80 ℃ for 12 hours, and finally respectively carrying out high-temperature treatment for 30min at 200 ℃ in air and 30min at 200 ℃ in hydrogen-argon mixed gas to obtain the 1% Pt/Na-Fe-3 catalyst.

Example 6

1.07mL of a 0.07M chloroplatinic acid aqueous solution was dissolved in 14.0mL of a 1M manganese nitrate solution, and the mixture was stirred uniformly to obtain a mixed solution A. Under the water bath condition of 80 ℃, uniformly dripping the mixed solution A into 212.3mL of 0.2M NaOH solution at the speed of 2mL/min, adjusting the pH to 8.5 by using 1M HCl after the dripping, continuing to stir and crystallize for 3h in the water bath of 80 ℃, and standing and aging for 1h in the water bath of 80 ℃.

And centrifugally washing the obtained precipitate until no chloride ions exist in the washing liquid, then placing the precipitate in an oven for drying at 80 ℃ for 12 hours, and finally respectively carrying out high-temperature treatment for 30min at 200 ℃ in air and 30min at 200 ℃ in hydrogen-argon mixed gas to obtain the 1% Pt/Na-Mn catalyst.

Example 7

Preparation of Pt-Na/Fe by Co-impregnation ₂ O ₃ A catalyst.

1.07mL of 0.07M chloroplatinic acid aqueous solution and 10mL of 4M NaOH solution were uniformly mixed and immersed in 1.2g of Fe ₂ O ₃ On the carrier, standing and aging for 12 hours after uniformly stirring, and then drying for 12 hours in an oven at 80 ℃.

The catalyst is treated for 30min at a high temperature of 200 ℃ in a hydrogen-argon mixed gas to obtain 1 percent Pt-Na/Fe ₂ O ₃ A catalyst.

Example 8

The integral Pt/Na-Fe/alumina honeycomb catalyst is prepared by adopting a slurry coating method.

1.07mL of 0.07M chloroplatinic acid aqueous solution, 14.0mL of 1M ferric nitrate solution and 1g of gamma-Al ₂ O ₃ The powder was dissolved in 50mL deionized water and stirred well to give a mixed solution a. 212.3mL of 0.2M NaOH solution is evenly dripped into the mixed solution A at the speed of 2mL/min under the water bath condition of 80 ℃, the pH is regulated to 8.5 by using 1M HCl after the dripping is finished, the water bath of 80 ℃ is continued to be stirred and crystallized for 3 hours, and then the mixture is stood for ageing for 1 hour in the water bath of 80 ℃. The precipitate obtained was washed centrifugally until no chloride ions were present in the washing solution, and then dried in an oven at 80℃for 12h.

2g of the catalyst powder, 20mg of surfactant (comprising 5mg of glycerol, 10mg of cellulose ether and 5mg of stearic acid) and 800mL of water are weighed, and ball-milled for 4 hours to prepare a slurry. And (3) dipping the cordierite honeycomb ceramic carrier in the coating slurry for 1h, drying at 80 ℃ for 12h, and finally treating at 200 ℃ for 30min in hydrogen-argon mixed gas to obtain the integral Pt/Na-Fe/alumina honeycomb catalyst.

Comparative example 1

Preparation of Pt-Fe/gamma-Al by co-impregnation ₂ O ₃ A catalyst.

1.07mL of a 0.07M aqueous solution of chloroplatinic acid and 14.0mL of a 1M solution of ferric nitrate were uniformly mixed and immersed in 1.2g of gamma-Al ₂ O ₃ On the carrier, standing and aging for 12 hours after uniformly stirring, and then drying for 12 hours in an oven at 80 ℃.

The catalyst is treated for 30min at a high temperature of 200 ℃ in a hydrogen-argon mixed gas to obtain 1 percent Pt-Fe/gamma-Al ₂ O ₃ A catalyst.

Comparative example 2

A50 mL single-neck flask was charged with a magnetic stirrer, 5mL of NaOH/glycol solution (0.50 mol/L) and 265. Mu.L of chloroplatinic acid/glycol solution (0.019 mol/L), the single-neck flask was fixed on an oil bath, a condenser tube was fitted, condensed water was introduced, ar shielding gas was introduced for 15 minutes, and then the upper opening of the condenser tube was sealed with a preservative film. The temperature of the oil bath was adjusted to 120 ℃, stirring was turned on, and stirring was carried out for 3 hours.

The single-neck flask is put out of an oil bath pot for cooling, the temperature of the oil bath pot is regulated to 80 ℃, and 0.1g of gamma-Al is weighed ₂ O ₃ Adding into a single-mouth flask, placing the single-mouth flask into the oil bath until the temperature of the oil bath is reduced to 80 ℃, opening stirring, taking down a condensing tube, plugging a bottle mouth by a plug, adding 1M HCl solution into the single-mouth flask by a syringe to adjust the pH value to 9, lifting the single-mouth flask from the oil bath to above the liquid level, and cooling to room temperature.

Centrifugally washing until no chloride ions exist in the washing liquid, then drying for 12 hours at 80 ℃ in an oven, and finally reducing for 30 minutes at 200 ℃ by taking hydrogen-argon mixed gas as reducing gas to obtain 1 percent Pt/gamma-Al ₂ O ₃ A catalyst.

Comparative example 3

A260 ml conical flask was charged with magnetic stirrer, 0.5g Carbon Nanotubes (CNTs), 110ml concentrated nitric acid and 8ml H ₂ O, stirring uniformly, then slowly adding 96mL of concentrated sulfuric acid while stirring, stirring for 5min, and performing ultrasonic treatment for 5min. Sealing with a preservative film, performing ultrasonic treatment at 60 ℃ for 2 hours, diluting with 2L of water, washing and filtering the CNT to be neutral, and drying the CNT in an oven at 100 ℃ for 12 hours.

The obtained CNT is put into a tube furnace and baked for 2 hours in an argon atmosphere at 1000 ℃ to obtain the CNT-O. The CNT-O is used as a carrier, the loading is carried out by equal volume dipping by using a chloroplatinic acid aqueous solution, and after the loading is finished, the carrier is aged for 12 hours under natural conditions and then dried for 12 hours at 100 ℃.

The mixture of hydrogen and argon is used as reducing gas, and the mixture is reduced for 30min at 200 ℃ to obtain the 1 percent Pt/CNT-O catalyst.

Comparative example 4

1.07mL of a 0.07M aqueous solution of chloroplatinic acid was dissolved in 14.0mL of a 1M solution of ferric nitrate, and the mixture was stirred uniformly to obtain a mixed solution A. Under the water bath condition of 80 ℃, uniformly dripping the mixed solution A) into 100mL of 0.2M NaOH solution at the speed of 2mL/min, adjusting the pH to 8.5 by using 1M HCl after the dripping, continuing to stir and crystallize for 3h in the water bath of 80 ℃, and then standing and aging for 1h in the water bath of 80 ℃.

And centrifugally washing the obtained precipitate until no chloride ions exist in the washing liquid, then placing the precipitate in an oven for drying at 80 ℃ for 12 hours, and finally, treating the precipitate in a hydrogen-argon mixed gas at 200 ℃ for 30 minutes to obtain the 1% Pt/Na-Fe-4 catalyst.

The contents of the raw material gases in the following experimental examples 1 to 3 are all by volume.

Experimental example 1

Evaluation conditions of the catalyst: the reaction pressure is normal pressure, and the reaction raw material gas is 85 percent CO ₂ +14.6％He+0.1％CO+0.3％H ₂ (80 mL/min) and air (5 mL/min), the catalyst loading volume was 1mL, and the space velocity was 5000h ^-1 . The CO catalytic oxidation conversion rate of the catalyst reaches the minimum reaction temperature T of 90 percent and 99 percent respectively ₉₀ And T ₉₉ See table 1.

Table 1 results of examples and comparative examples

The catalyst product obtained in example 3 was tested for catalytic stability of 1% Pt/Na-Fe-1, as shown in FIG. 1, and the catalyst maintained stable catalytic performance over 20 hours with a CO conversion of substantially about 99%.

Experimental example 2

Evaluation conditions of the catalyst: the reaction pressure is normal pressure, and the reaction raw material gas is 85 percent CO ₂ +14.6％He+0.1％CO+0.3％H ₂ (80 mL/min), air (5 mL/min) and 100ppm H ₂ S gas (3.5 mL/min), catalyst loading volume of 1mL, space velocity of 5000h ^-1 . The CO catalytic oxidation conversion rate of the catalyst reaches the minimum reaction temperature T of 90 percent and 99 percent respectively ₉₀ And T ₉₉ See table 2, wherein the results with the label "-" indicate that the catalyst activity was unable to achieve this conversion.

Table 2 results of examples and comparative examples

Experimental example 3

Evaluation conditions of the catalyst: the reaction pressure is normal pressure, and the reaction raw material gas is 49% H ₂ +50% He+1% CO (80 mL/min) and air (2 mL/min), the catalyst loading volume was 1mL, and the space velocity was 5000h ^-1 . The CO catalytic oxidation conversion rate of the catalyst reaches the minimum reaction temperature T of 90 percent and 99 percent respectively ₉₀ And T ₉₉ See table 3, where the results with the label "-" indicate that the catalyst activity was unable to achieve this conversion.

Table 3 results of examples and comparative examples

Catalyst	T ₉₀ (℃)	T ₉₉ (℃)
			Example 1	45	50
Example 2	45	55
			Example 3	40	50
Example 4	60	105
			Example 5	35	40
Example 6	75	100
			Example 7	135	160
Example 8	65	90
			Comparative example 1	-	-
Comparative example 2	145	180
			Comparative example 3	100	130

Claims

1. Use of a catalyst in a CO oxidation reaction, said catalyst comprising: taking Pt element as an active component, a transition metal element M2 oxide and alkali metal elements M1 and M2 as one of Mn and Fe elements, wherein the alkali metal element M1 is selected from Na and/or K elements, the Pt element accounts for 0.1-2wt% of the total mass of the catalyst, the M1 element accounts for 1-10wt% of the total mass of the catalyst, the rest is the content of various forms of substances of the transition element M2, the catalyst is prepared by adopting a coprecipitation method,

wherein the reaction system contains hydrogen-rich, carbon dioxide-rich or/and sulfur-containing.

2. Use according to claim 1, characterized in that M2 is selected from one of the elements Mn and Fe, the mass of Pt being 0.15-3% of the mass of M2 oxide.

3. The use according to claim 1, wherein the transition metal element M2 is an Mn element.

4. The use of claim 1, wherein the catalyst is prepared by a process comprising: and (3) mixing the Pt precursor solution and the M2 precursor solution to obtain a mixed solution A, dropwise adding the mixed solution A into an alkali solution containing M1 element, adjusting pH=7-10 after the dropwise adding is finished to obtain a mixture B, and crystallizing, washing and treating the mixture B at high temperature to obtain the catalyst.

5. The use according to claim 4, wherein the ratio of the amount of the substance of element M1 in the solution of element M1 to the sum of the amount of the substance of Pt in the Pt precursor solution and the amount of the substance of M2 in the M2 precursor solution is 2:1 to 4:1.

6. the method according to claim 4, wherein the high temperature treatment is heating at a temperature of 150-400 ℃.

7. The use according to claim 4, wherein the high temperature treatment is heating at a temperature of 150-250 ℃.

8. Use according to any of claims 4-7, characterized in that the drying step is performed before the high temperature treatment, the drying temperature being below 100 ℃.

9. The use according to any one of claims 4-7, wherein the Pt precursor is a water-soluble platinum element-containing salt solution;

the M2 precursor is water-soluble salt solution containing M2 element;

the M1 element-containing solution comprises M1OH or M1 ₂ CO ₃ 。

10. Use according to claim 6 or 7, characterized in that the treatment at high temperature is carried out in an air atmosphere or in a hydrogen-containing gas mixture.

11. Use according to claim 6 or 7, characterized in that the high temperature treatment is performed in an air atmosphere and then in a hydrogen-containing gas mixture.

12. The use according to any one of claims 4-7, wherein the drying step is performed before the high temperature treatment, the drying temperature being 70-100 ℃.

13. Use according to claim 9, wherein the salt solution containing platinum element comprises chloroplatinic acid or platinum chloride.

14. Use according to claim 9, characterized in that the salt solution of M2 element is nitrate or chloride salt containing M2 element.

15. Use according to claim 9, characterized in that the concentration of the solution of M1 element is between 0.1 and 0.5M.

16. A use according to any one of claims 1 to 3, characterized in that the catalyst is prepared by a process comprising:

17. Use according to claim 16, characterized in that the mass of Pt element is 0.5-2% of the mass of alumina.