CN112023921B - A kind of preparation method of Pt-based catalyst with highly dispersed active components - Google Patents

Abstract

The invention relates to a preparation method of a Pt-based catalyst with a high dispersion active component, which comprises the following steps: (1) Taking Sn-containing alumina as a carrier, adding an ethylenediamine tetraacetic acid potassium solution, and carrying out suction filtration to obtain an alumina carrier sample containing Sn and K; (2) After the obtained product is vacuumized, adding an ethanol solution containing porphyrin Pt, heating and refluxing under a vacuum state, stopping refluxing, and continuously evaporating the solvent; (3) Heating the obtained product in nitrogen atmosphere, cutting into nitrogen mixed gas containing HCl and water vapor, treating for a certain time, and then introducing nitrogen for cooling; (4) And (3) dipping the obtained product into an alkali metal auxiliary agent K, and drying and roasting to obtain the Pt-based catalyst with high dispersion of the active components of the target product. The invention can realize high dispersion of Pt, reduce the Pt consumption, has stable active phase structure, good activity, high propylene selectivity and strong stability, and is beneficial to the industrial production of the catalyst.

Description

A kind of preparation method of Pt-based catalyst with highly dispersed active components

technical field

The invention relates to a method for preparing a highly dispersed dehydrogenation catalyst, in particular to a method for preparing a Pt-based catalyst with highly dispersed active components.

Background technique

Propylene is one of the most important basic raw materials for the chemical industry. In the past five years, the average annual growth rate was 1.8 times of GDP. The production capacity of propylene in the traditional process is seriously insufficient, and an alternative process for propylene production must be sought. Propane dehydrogenation to propylene technology (PDH) is the most competitive approach and will become one of the key technologies for countries to ensure their core competitiveness in the global competition of the petrochemical industry.

Supported Pt-based catalysts are widely used in propane dehydrogenation technology. The main problem currently facing is: the active component Pt is highly sensitive to heat at high temperatures, and it is easy to migrate, agglomerate or even sinter, making it difficult to maintain a high degree of dispersion, resulting in the Pt active phase catalysis. The efficiency drops rapidly, the amount of carbon deposits increases sharply, and even the Pt active phase is permanently deactivated due to sintering. Internationally, process strategies such as adding diluent hydrogen and negative pressure operation are used to achieve the purpose of improving catalyst selectivity and stability and delaying its deactivation. However, this does not essentially solve the problems of poor high-temperature stability and rapid carbon deposition and deactivation of catalysts. Therefore, how to realize the controllable preparation of the active phase, construct the Pt active phase with a high-temperature stable structure, and improve its catalytic efficiency and lifetime are the main challenges for the development of Pt-based propane dehydrogenation catalysts.

The CN1579616 patent provides a catalyst for the dehydrogenation of straight-chain alkanes with large pores, low bulk ratio, and double-pore structure γ-Al ₂ O ₃ pellets as a carrier. Through the modulation of the catalyst, the low-carbon Reactive properties of alkanes dehydrogenation. USP4,914,075 discloses a Pt-based catalyst supported by aluminum oxide for the dehydrogenation of propane and other low-carbon alkanes, which has high alkane conversion and olefin selectivity. CN1201715 patent discloses the preparation method of Pt-Sn-K/Al ₂ O ₃ catalyst for the dehydrogenation of light alkanes. USP4,914,075, USP4,353,815, EP98,622, etc. have all reported Pt-based catalysts for propane and other low-carbon alkanes dehydrogenation, with high alkane conversion and olefin selectivity. Although these catalysts have high alkane conversion and olefin selectivity under certain reaction conditions, they are prone to carbon deposition and deactivation under high temperature conditions, resulting in poor stability of catalytic reactions and short service life of catalysts. There have been a lot of reports on the propane dehydrogenation of Pt-Sn catalysts supported by alumina at home and abroad, but the catalyst activity, stability, product selectivity and preparation economy are often not considered. The traditional Pt-based propane dehydrogenation catalyst uses alumina as the carrier. When Pt is introduced by the impregnation method, the alumina carrier has a strong adsorption effect on the Pt precursor. It is impossible to reduce the amount of Pt, and it is easy to aggregate and grow during the reaction process, which reduces the conversion rate of propane and the selectivity of propylene.

Contents of the invention

Aiming at the deficiencies of the prior art, the present invention provides a method for preparing a Pt-based catalyst with highly dispersed active components. The catalyst prepared by the method can realize high dispersion of Pt, stable active phase structure, and has better activity, selectivity, Stability and low coke rate of raw materials.

In order to solve the problems of the technologies described above, the present invention is achieved in that:

A method for preparing a Pt-based catalyst with highly dispersed active components, comprising the steps of:

(1) Take Sn-containing alumina as a carrier, add potassium edetate solution, and filter with suction to obtain an alumina carrier sample containing Sn and K;

(2) After vacuumizing the product obtained in step (1), add an ethanol solution containing porphyrin Pt, heat to reflux under vacuum, stop the reflux, and continue to evaporate the solvent to dryness;

(3) the product obtained in step (2) is heated up under a nitrogen atmosphere, then cut into a nitrogen gas mixture containing HCl and water vapor, and then feed nitrogen to cool down after a certain period of time;

(4) The product obtained in step (3) is impregnated with the alkali metal additive K, and after drying and roasting, a Pt-based catalyst with highly dispersed active components of the target product is obtained.

As a preferred solution, in the step (1) of the present invention, the Sn-containing alumina carrier is spherical, strip-shaped, microsphere or special-shaped; the specific surface of the Sn-containing alumina carrier is 170-260m ² /g, and the pores The volume is 0.40～0.90cm ³ /g.

The Sn in the above-mentioned Sn-containing alumina carrier can be introduced during the alumina gelling process, can also be introduced in the form of loading, and can also be introduced during the alumina forming process by kneading.

Further, in the step (1) of the present invention, the potassium ethylenediaminetetraacetic acid solution is prepared by mixing ethylenediaminetetraacetic acid, potassium hydroxide and water.

Further, the molar ratio of ethylenediaminetetraacetic acid to potassium hydroxide in the present invention is 1:4-10, preferably 1:6-8; The mass concentration is 0.01-0.3 mol/L, preferably 0.05-0.2 mol/L.

Further, in step (1) of the present invention, based on 1L of potassium ethylenediaminetetraacetic acid solution, the amount of Sn-containing alumina added is 50-300g, preferably 100-200g; fully stirred for 1-24h, preferably 4 ~8h.

Further, in step (2) of the present invention, after vacuumizing the product obtained in step (1) for 0.3 to 2 hours, preferably 0.5 to 1.2 hours, add the ethanol solution containing porphyrin Pt, and heat to 40 ~80°C, preferably 50~70°C, keep reflux for 1~6h, preferably 2~4h; the ratio of the volume of the ethanol solution containing porphyrin Pt to the volume of the product obtained in step (1) is 4~6:1.

Further, in the step (3) of the present invention, at a temperature of 120-240°C, preferably 160-200°C, cut into the nitrogen mixture containing HCl and water vapor, and treat for 1-8h, preferably 2-4h The volumetric space velocity is 200-2000h ^-1 , preferably 500h ^- 1-1000h ^-1 ; in the nitrogen gas mixture, the volume content of HCl is 1-10%, preferably 2-4%; the volume content of water vapor 5 to 30%, preferably 10 to 20%.

Further, in step (4) of the present invention, the product obtained in step (3) is then impregnated with alkali metal additive K, aged at room temperature for 2 to 16 hours, preferably 4 to 8 hours, and dried at 40 to 160°C for 2 to 16 hours , preferably drying at 80-120°C for 4h-8h, sintering at 400-800°C for 2-20h, preferably at 500-700°C for 4-8h, preferably at 450-600°C for 6-18h.

Further, in the Pt-based catalyst with highly dispersed active components of the present invention, the weight percentage of Pt is 0.1-1.0% by weight, preferably 0.2-0.5% by weight; the weight percentage of Sn by weight is 0.2-10% by weight. ; Preferably 0.5-5%; K is 0.3-4% by weight of the element, preferably 0.3-3%.

Further, in the step (2) of the present invention, the porphyrin Pt is platinum octaethylporphyrin; the alkali metal additive K is potassium nitrate. The alkali metal additive K is a soluble K-containing salt, which can be an inorganic salt or an organic salt, and is preferably potassium nitrate.

In the present invention, potassium ethylenediamine tetraacetate is highly dispersed on the surface of Sn-containing alumina in advance, and porphyrin platinum with a larger kinetic diameter is loaded. Under the combined action of HCl and water vapor, in the presence of hydroxyl radicals Under this condition, the large π ring of porphyrin is destroyed, the conjugation effect is lost, and the stability of porphyrin platinum decreases accordingly. Chloride ions have a stronger affinity with platinum in porphyrin platinum, and the platinum is eluted from the coordination structure, and then Migrate to the vicinity of EDTA and replace the potassium combined with EDTA to form a complex of EDTA and Pt. After drying and roasting, a highly dispersed Pt-containing catalyst is obtained. The preparation method can realize the high dispersion of Pt and reduce the consumption of Pt, the structure of the active phase is stable, the activity is good, the selectivity of propylene is high, and the stability is strong. The catalyst preparation method of the invention is simple, the process technology is mature, and is beneficial to the industrial production of the catalyst.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. The scope of protection of the present invention is not limited to the expression of the following content.

Fig. 1 is the transmission electron microscope picture of the catalyst obtained in embodiment 2.

Detailed ways

Example 1

Weigh a certain amount of ethylenediaminetetraacetic acid powder and solid potassium hydroxide with a molar ratio of 1:7 respectively, add them into deionized water, stir thoroughly, and prepare a mixture containing A mixed solution of potassium edetate and potassium hydroxide.

Weigh 75 g of the dried Sn-containing alumina carrier (spherical, 1.6 mm in diameter, 0.56 cm ³ /g pore volume, 224 m ² /g specific surface area, the carrier is used in the following examples), and add it to 500 mL ethylenediamine-containing Potassium tetraacetate solution, fully stirred for 6h, then suction filtered. The solid obtained after suction filtration was placed in a rotary evaporator, and after vacuum treatment for 1 hour, 375 mL of ethanol solution containing a certain amount of platinum octaethylporphyrin was added, heated at 60°C under vacuum, and treated for 3 hours, reflux was stopped, and continued to evaporate to dryness Solvent, cool down and take out the solid. Place the obtained solid in a fixed-bed reactor, raise the temperature to 180°C under nitrogen atmosphere, then cut into the nitrogen gas containing 3% HCl volume concentration and 15% water vapor volume concentration, the volume space velocity is 750h ^-1 , and treat for 3h After that, switch to nitrogen and cool down. Prepare a certain concentration of potassium nitrate solution 75mL, add it to 50g of solids treated with HCl and water vapor in nitrogen, age for 10h, dry at 100°C for 6h, and roast at 500°C for 10h to obtain catalyst C-1, each component in the catalyst The content is: Pt 0.3wt%, Sn 1wt%, K 2wt%. The particle size distribution of Pt crystal grains in the range of 1nm-3nm is 93%. Evaluation conditions: at 600°C, the mass space velocity of propane is 2h ^-1 , the propane dehydrogenation reaction is carried out under normal pressure conditions, and the amount of catalyst used is 3g. The evaluation results are shown in Table 1.

Example 2

Weigh a certain amount of ethylenediaminetetraacetic acid powder and solid potassium hydroxide with a molar ratio of 1:6, add them into deionized water, stir well, and prepare a mixture containing A mixed solution of potassium edetate and potassium hydroxide.

Weigh 100 g of the dried Sn-containing alumina carrier (spherical, 1.6 mm in diameter, 0.56 cm ³ /g pore volume, 224 m ² /g specific surface area, the carrier is used in the following examples), and add it to 500 mL ethylenediamine-containing Potassium tetraacetate solution, fully stirred for 4h, then suction filtered. The solid obtained after suction filtration was placed in a rotary evaporator, and after vacuum treatment for 1.2 hours, 400 mL of ethanol solution containing a certain amount of octaethylporphyrin platinum was added, and the temperature was heated to 50 °C under vacuum, and treated for 4 hours, and the reflux was stopped, and the evaporation was continued. The solvent was dried, and the solid was removed by cooling. Place the obtained solid in a fixed-bed reactor, raise the temperature to 160°C under a nitrogen atmosphere, then cut into the nitrogen gas containing 4% HCl volume concentration and 20% water vapor volume concentration, and treat for 4h at a volume space velocity of 500h ^-1 After that, switch to nitrogen and cool down. Prepare a certain concentration of potassium nitrate solution 75mL, add it to 50g of solids treated with HCl and water vapor in nitrogen, age for 16h, dry at 80°C for 4h, and roast at 450°C for 18h to obtain catalyst C-2, each component in the catalyst The content is: Pt0.5wt%, Sn 5wt%, K 3wt%. The particle size distribution of Pt crystal grains in the range of 1nm-3nm is 96%. Evaluation conditions: at 600°C, the mass space velocity of propane is 2h ^-1 , the propane dehydrogenation reaction is carried out under normal pressure conditions, and the amount of catalyst used is 3g. The evaluation results are shown in Table 1.

Example 3

Weigh a certain amount of ethylenediaminetetraacetic acid powder and solid potassium hydroxide with a molar ratio of 1:8 respectively, add them into deionized water, stir thoroughly, and prepare a mixture containing A mixed solution of potassium edetate and potassium hydroxide.

Weigh 50 g of dried Sn-containing alumina carrier (spherical shape, diameter 1.6 mm, pore volume 0.56 cm ³ /g, specific surface area 224 m ² /g, the carrier used in the following examples), and add it to 500 mL ethylenediamine-containing Potassium tetraacetate solution, fully stirred for 4h, then suction filtered. The solid obtained after suction filtration was placed in a rotary evaporator, and after vacuum treatment for 0.5 h, 300 mL of ethanol solution containing a certain amount of octaethylporphyrin platinum was added, and the temperature was heated to 70 °C under vacuum, and treated for 2 h, and the reflux was stopped, and the evaporation was continued. The solvent was dried, and the solid was removed by cooling. Place the obtained solid in a fixed-bed reactor, raise the temperature to 160°C under a nitrogen atmosphere, then cut into the nitrogen gas containing 2% HCl volume concentration and 10% water vapor volume concentration, and treat for 2 hours at a volume space velocity of 1000h ^-1 After that, switch to nitrogen and cool down. Prepare a certain concentration of potassium nitrate solution 75mL, add it to 50g of solids treated with HCl and water vapor in nitrogen, age for 10h, dry at 120°C for 4h, and roast at 600°C for 6h to obtain catalyst C-3, each component in the catalyst The content is: Pt0.2%, Sn 0.5%, K 1.0wt%. The particle size distribution of Pt crystal grains in the range of 1nm-3nm is 92%. Evaluation conditions: at 600°C, the mass space velocity of propane is 2h ^-1 , the propane dehydrogenation reaction is carried out under normal pressure conditions, and the amount of catalyst used is 3g. The evaluation results are shown in Table 1.

Example 4

Weigh a certain amount of ethylenediaminetetraacetic acid powder and solid potassium hydroxide with a molar ratio of 1:7 respectively, add them into deionized water, stir thoroughly, and prepare a mixture containing A mixed solution of potassium edetate and potassium hydroxide.

Weigh 100 g of the dried Sn-containing alumina carrier (spherical, 1.6 mm in diameter, 0.56 cm ³ /g pore volume, 224 m ² /g specific surface area, the carrier is used in the following examples), and add it to 500 mL ethylenediamine-containing Potassium tetraacetate solution, fully stirred for 4h, then suction filtered. The solid obtained after suction filtration was placed in a rotary evaporator, and after vacuum treatment for 0.8h, 500mL of ethanol solution containing a certain amount of platinum octaethylporphyrin was added, and the temperature was heated to 60°C under vacuum, and treated for 3h, and the reflux was stopped, and the evaporation was continued. The solvent was dried, and the solid was removed by cooling. Put the obtained solid in a fixed-bed reactor, raise the temperature to 160°C under a nitrogen atmosphere, then cut into the nitrogen gas containing 3% HCl volume concentration and 15% water vapor volume concentration, the volume space velocity is 900h ^-1 , and treat for 4h After that, switch to nitrogen and cool down. Prepare a certain concentration of potassium nitrate solution 75mL, add it to 50g solid containing HCl and water vapor after nitrogen treatment, age for 4h, dry at 100°C for 6h, and roast at 500°C for 8h to obtain catalyst C-4, each component in the catalyst The content is: Pt 0.3wt%, Sn 2wt%, K 1wt%. The particle size distribution of Pt crystal grains in the range of 1nm-3nm is 95%. Evaluation conditions: at 600°C, the mass space velocity of propane is 2h ^-1 , the propane dehydrogenation reaction is carried out under normal pressure conditions, and the amount of catalyst used is 3g. The evaluation results are shown in Table 1.

Example 5

Weigh a certain amount of ethylenediaminetetraacetic acid powder and solid potassium hydroxide with a molar ratio of 1:7 respectively, add them into deionized water, stir thoroughly, and prepare a mixture containing A mixed solution of potassium edetate and potassium hydroxide.

Weigh 75 g of the dried Sn-containing alumina carrier (spherical, 1.6 mm in diameter, 0.56 cm ³ /g pore volume, 224 m ² /g specific surface area, the carrier is used in the following examples), and add it to 500 mL ethylenediamine-containing Potassium tetraacetate solution, fully stirred for 6h, then suction filtered. The solid obtained after suction filtration was placed in a rotary evaporator, and after vacuum treatment for 0.7h, 300mL ethanol solution containing a certain amount of octaethylporphyrin platinum was added, and the temperature was heated to 60°C in a vacuum state, and treated for 3h, and the reflux was stopped, and the evaporation was continued. The solvent was dried, and the solid was removed by cooling. The obtained solid is placed in a fixed bed reactor, under a nitrogen atmosphere, the temperature is raised to 180 ° C, and then cut into nitrogen containing 3% HCl volume concentration and 15% water vapor volume concentration, the volume space velocity is 800h, after 3h treatment, Switch to nitrogen and cool down. Prepare a certain concentration of potassium nitrate solution 75mL, add it to 50g solid containing HCl and water vapor after nitrogen treatment, age for 4h, dry at 100°C for 6h, and roast at 500°C for 8h to obtain catalyst C-4, each component in the catalyst The content is: Pt0.4wt%, Sn3.0%, K2.0wt%. The particle size distribution of Pt crystal grains in the range of 1nm-3nm is 94%. Evaluation conditions: at 600°C, the mass space velocity of propane is 2h ^-1 , the propane dehydrogenation reaction is carried out under normal pressure conditions, and the amount of catalyst used is 3g. The evaluation results are shown in Table 1.

Comparative example 1

Weigh 75 g of the dried Sn-containing alumina carrier (spherical, 1.6 mm in diameter, 0.56 cm ³ /g in pore volume, 224 m ² /g in specific surface area, which is used in the following examples) and place it in a rotary evaporator. After vacuum treatment for 1 hour, add 375 mL ethanol solution containing a certain amount of platinum octaethylporphyrin, heat at 60°C under vacuum, treat for 3 hours, stop reflux, continue to evaporate the solvent, cool down and take out the solid. Place the obtained solid in a fixed-bed reactor, raise the temperature to 180°C under nitrogen atmosphere, then cut into the nitrogen gas containing 3% HCl volume concentration and 15% water vapor volume concentration, the volume space velocity is 750h ^-1 , and treat for 3h After that, switch to nitrogen and cool down. Prepare a certain concentration of potassium nitrate solution 75mL, add it to 50g of solids treated with HCl and water vapor in nitrogen, age for 10h, dry at 100°C for 6h, and roast at 500°C for 10h to obtain catalyst D-1, each component in the catalyst The content is: Pt 0.3wt%, Sn 1wt%, K 2wt%. The particle size distribution of Pt crystal grains in the range of 1nm-3nm is 52%. Evaluation conditions: at 600°C, the mass space velocity of propane is 2h ^-1 , the propane dehydrogenation reaction is carried out under normal pressure conditions, and the amount of catalyst used is 3g. The evaluation results are shown in Table 1.

Comparative example 2

Weigh a certain amount of ethylenediaminetetraacetic acid powder and solid potassium hydroxide with a molar ratio of 1:7, add them into deionized water, stir well, and prepare a mixture containing Potassium EDTA is a solution of molar concentration in terms of EDTA.

Weigh 75 g of the dried Sn-containing alumina carrier (spherical, 1.6 mm in diameter, 0.56 cm ³ /g pore volume, 224 m ² /g specific surface area, the carrier is used in the following examples), and add it to 500 mL ethylenediamine-containing Potassium tetraacetate solution, fully stirred for 6h, then suction filtered. The solid obtained after suction filtration was placed in a rotary evaporator, and after vacuum treatment for 1 hour, 375 mL of an aqueous solution containing a certain amount of chloroplatinic acid was added, heated at 60°C under vacuum, and treated for 3 hours, and the reflux was stopped. solid. Place the obtained solid in a fixed-bed reactor, raise the temperature to 180°C under nitrogen atmosphere, then cut into the nitrogen gas containing 3% HCl volume concentration and 15% water vapor volume concentration, the volume space velocity is 750h ^-1 , and treat for 3h After that, switch to nitrogen and cool down. Prepare a certain concentration of potassium nitrate solution 75mL, add it to 50g of solids treated with HCl and water vapor in nitrogen, age for 10h, dry at 100°C for 6h, and roast at 500°C for 10h to obtain catalyst D-2, each component in the catalyst The content is: Pt 0.3wt%, Sn 1wt%, K 2wt%. The particle size distribution of Pt crystal grains in the range of 1nm-3nm is 72%. Evaluation conditions: at 600°C, the mass space velocity of propane is 2h ^-1 , the propane dehydrogenation reaction is carried out under normal pressure conditions, and the amount of catalyst used is 3g. The evaluation results are shown in Table 1.

The reaction performance of table 1 catalyst

The description of the present invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and changes will be apparent to those of ordinary skill in the art. The embodiment was chosen and described in order to better explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention and design various embodiments with various modifications as are suited to the particular use. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

Claims (5)

1. A method for preparing a Pt-based catalyst with highly dispersed active components, characterized in that it comprises the steps of: taking a certain amount of ethylenediaminetetraacetic acid powder and solid potassium hydroxide with a molar ratio of 1:7 respectively, adding to In deionized water, stir fully, and prepare a mixed solution containing potassium ethylenediaminetetraacetic acid and potassium hydroxide with a molar concentration of 0.15mol/L in terms of ethylenediaminetetraacetic acid; weigh 75g of the dried alumina carrier containing Sn, Spherical, diameter 1.6mm, pore volume 0.56cm ³ /g, specific surface area 224m ² /g, add to 500mL solution containing potassium ethylenediaminetetraacetate, stir well for 6h, and then filter with suction; the solid obtained after suction filtration is placed in rotary evaporation In the instrument, after vacuum treatment for 1 hour, add 375mL ethanol solution containing a certain amount of octaethylporphyrin platinum, heat the temperature at 60°C under vacuum, treat for 3 hours, stop reflux, continue to evaporate the solvent, cool down and take out the solid; Place in a fixed-bed reactor, raise the temperature to 180°C under a nitrogen atmosphere, then cut into the nitrogen gas containing 3% HCl volume concentration and 15% water vapor volume concentration, and the volume space velocity is 750h ^-1 , after 3 hours of treatment, switch to Nitrogen, lower the temperature; prepare 75mL of a certain concentration of potassium nitrate solution, add it to 50g of nitrogen-treated solid containing HCl and water vapor, age for 10h, dry at 100°C for 6h, and roast at 500°C for 10h to obtain catalyst C-1. The content of each component in the catalyst is: 0.3wt% of Pt, 1wt% of Sn, 2wt% of K; the particle size distribution of Pt grains in the range of 1nm to 3nm is 93%. 2. A method for preparing a Pt-based catalyst with highly dispersed active components, characterized in that it comprises the steps of: taking a certain amount of ethylenediaminetetraacetic acid powder and solid potassium hydroxide with a molar ratio of 1:6 respectively, adding to In deionized water, stir fully, and prepare a mixed solution containing potassium ethylenediaminetetraacetic acid and potassium hydroxide with a molar concentration of 0.2 mol/L in terms of ethylenediaminetetraacetic acid; weigh 100 g of the dried alumina carrier containing Sn, Spherical shape, diameter 1.6mm, pore volume 0.56cm ³ /g, specific surface area 224m ² /g, 100g, add to 500mL solution containing potassium ethylenediaminetetraacetate, stir well for 4h, then suction filter; In the rotary evaporator, after vacuuming for 1.2 hours, add 400 mL of ethanol solution containing a certain amount of octaethylporphyrin platinum, heat at 50°C under vacuum, and process for 4 hours, stop reflux, continue to evaporate the solvent, cool down and take out the solid , put the obtained solid in a fixed bed reactor, raise the temperature to 160°C under a nitrogen atmosphere, then cut into the nitrogen gas containing 4% HCl volume concentration and 20% water vapor volume concentration, and the volume space velocity is 500h ^-1 . After 4h, switch to nitrogen, lower the temperature, prepare 75mL of potassium nitrate solution with a certain concentration, add it to 50g of nitrogen-treated solid containing HCl and water vapor, age for 16h, dry at 80°C for 4h, and roast at 450°C for 18h to obtain the catalyst C-2, the content of each component in the catalyst is: Pt 0.5wt%, Sn 5wt%, K 3wt%; the particle size distribution of Pt crystal grains in the range of 1nm to 3nm is 96%. 3. A method for preparing a Pt-based catalyst with highly dispersed active components, comprising the steps of: taking a certain amount of ethylenediaminetetraacetic acid powder and solid potassium hydroxide with a molar ratio of 1:8 respectively, adding to In deionized water, stir fully, and prepare a mixed solution containing potassium ethylenediaminetetraacetic acid and potassium hydroxide with a molar concentration of 0.05mol/L in terms of ethylenediaminetetraacetic acid; weigh 50g of the dried alumina carrier containing Sn, Spherical, diameter 1.6mm, pore volume 0.56cm ³ /g, specific surface area 224m ² /g, add to 500mL solution containing potassium ethylenediaminetetraacetate, stir well for 4h, then filter with suction, and place the solid obtained after suction filtration in a rotary evaporator In the instrument, after vacuuming for 0.5h, add 300 mL of ethanol solution containing a certain amount of octaethylporphyrin platinum, heat the temperature at 70°C under vacuum state, treat for 2h, stop reflux, continue to evaporate the solvent, cool down and take out the solid. The obtained solid was placed in a fixed-bed reactor, heated up to 160°C under a nitrogen atmosphere, and then cut into nitrogen containing 2% HCl volume concentration and 10% water vapor volume concentration, and the volume space velocity was 1000h ^-1 , after 2 hours of treatment , switch to nitrogen, lower the temperature; configure a certain concentration of potassium nitrate solution 75mL, add it to 50g of nitrogen-treated solid containing HCl and water vapor, age for 10h, dry at 120°C for 4h, and roast at 600°C for 6h to obtain catalyst C- 3. The content of each component in the catalyst is: Pt 0.2wt%, Sn 0.5wt%, K 1.0wt%, and the particle size distribution of Pt grains in the range of 1nm to 3nm is 92%. 4. A method for preparing a Pt-based catalyst with highly dispersed active components, characterized in that it comprises the steps of: taking a certain amount of ethylenediaminetetraacetic acid powder and solid potassium hydroxide with a molar ratio of 1:7 respectively, adding to In deionized water, stir fully, and prepare a mixed solution containing potassium ethylenediaminetetraacetic acid and potassium hydroxide with a molar concentration of 0.15 mol/L in terms of ethylenediaminetetraacetic acid; weigh 100 g of the dried alumina carrier containing Sn, Spherical shape, diameter 1.6mm, pore volume 0.56cm ³ /g, specific surface area 224m ² /g, add to 500mL solution containing potassium edetate, stir well for 4 hours, and then filter with suction; the solid obtained after suction filtration is placed in rotary evaporation In the instrument, after vacuum treatment for 0.8h, add 500 mL ethanol solution containing a certain amount of octaethylporphyrin platinum, heat the temperature at 60°C under vacuum state, treat for 3h, stop reflux, continue to evaporate the solvent, cool down and take out the solid; The obtained solid was placed in a fixed-bed reactor, heated up to 160°C under a nitrogen atmosphere, and then cut into nitrogen containing 3% HCl volume concentration and 15% water vapor volume concentration, and the volume space velocity was 900h ^-1 , after 4 hours of treatment , switch to nitrogen, lower the temperature, configure a certain concentration of potassium nitrate solution 75mL, add it to 50g of nitrogen-treated solid containing HCl and water vapor, age for 4h, dry at 100°C for 6h, and roast at 500°C for 8h to obtain catalyst C- 4. The content of each component in the catalyst is: Pt 0.3wt%, Sn 2wt%, K 1wt%; the particle size distribution of Pt grains in the range of 1nm to 3nm is 95%. 5. A method for preparing a Pt-based catalyst with highly dispersed active components, comprising the steps of: taking a certain amount of ethylenediaminetetraacetic acid powder and solid potassium hydroxide with a molar ratio of 1:7 respectively, adding to In deionized water, stir fully, and prepare a mixed solution containing potassium ethylenediaminetetraacetic acid and potassium hydroxide with a molar concentration of 0.15 mol/L in terms of ethylenediaminetetraacetic acid; weigh 75 g of the dried alumina carrier containing Sn, Spherical, diameter 1.6mm, pore volume 0.56cm ³ /g, specific surface area 224m ² /g, add to 500mL solution containing potassium ethylenediaminetetraacetate, stir well for 6h, then filter with suction, and place the solid obtained after suction filtration in a rotary evaporator In the instrument, after vacuum treatment for 0.7h, add 300 mL ethanol solution containing a certain amount of octaethylporphyrin platinum, heat the temperature at 60°C under vacuum state, treat for 3h, stop reflux, continue to evaporate the solvent, cool down and take out the solid; The obtained solid was placed in a fixed-bed reactor, heated up to 180°C under a nitrogen atmosphere, and then cut into nitrogen containing 3% HCl volume concentration and 15% water vapor volume concentration, and the volume space velocity was 800h ^-1 , after 3 hours of treatment , switch to nitrogen, lower the temperature, configure a certain concentration of potassium nitrate solution 75mL, add it to 50g of nitrogen-treated solid containing HCl and water vapor, age for 4h, dry at 100°C for 6h, and roast at 500°C for 8h to obtain catalyst C- 4. The content of each component in the catalyst is: Pt 0.4 wt%, Sn 3.0 wt%, K 2.0 wt%, and the particle size distribution of Pt crystal grains in the range of 1nm to 3nm is 94%.