Preparation method of expansible graphite composite ferroferric oxide loaded platinum catalyst material and application of expansible graphite composite ferroferric oxide loaded platinum catalyst material in CO catalytic oxidation under conditions of H2O and SO2

Abstract

The invention discloses a preparation method of an expandable graphite (EG) composite ferroferric oxide loaded platinum catalyst for CO catalytic oxidation in the presence of H2O and SO2. The method is characterized in that soluble ferric salt and platinum salt are used as main raw materials, alkali is used as a precipitator, and a Pt / Fe3O4 catalyst material is prepared by adopting a coprecipitation method. In order to improve the hydrophobicity and sulfur resistance, a Pt / Fe3O4 catalyst and expandable graphite (EG) are compounded by adopting a mechanical grinding method to obtain an EG-Pt / Fe3O4 catalyst material. The preparation method is simple and low in cost. The prepared catalyst not only has high catalytic activity, but also has excellent SO2 poisoning resistance. Besides, the catalyst is wide in application field, has important value for promoting environmental protection and reducing pollution emission, and has far-reaching significance for constructing a green and sustainable ecological environment.

Description

Technical Field

[0001] The invention relates to the technical field of catalyst preparation, and in particular to a method for preparing expandable graphite (EG) composite ferroferric oxide supported platinum catalyst by coprecipitation and mechanical grinding, and application of the catalyst in catalytic oxidation of CO under H2O and SO2 conditions. Background Art

[0002] CO emissions rank first in the sintering flue gas of steel plants. Due to its complex composition, high temperature and humidity, high oxygen and sulfur content, and large amount of dust, strict requirements are placed on the stability of CO catalysts. To meet this challenge, steel mills widely use technical means such as desulfurization, denitrification and dust removal to reduce the emission of harmful substances. However, even after desulfurization treatment, the low concentration of SO2 remaining in the flue gas will still cause ordinary CO catalytic oxidation catalysts to be poisoned and lose their activity. In recent years, it has been found that loading trace amounts of platinum on ferroferric oxide carriers has excellent catalytic performance for CO. And compounding it with expandable graphite (EG) can significantly improve the stability of the catalyst and its resistance to sulfur dioxide poisoning. This catalyst is low in cost and simple to prepare, and has great practical production application value, which can bring new breakthroughs to flue gas treatment technology. Summary of the invention

[0003] The purpose of the present invention is to provide a method for preparing an expandable graphite (EG) composite ferroferric oxide supported platinum catalyst for CO catalytic oxidation under H2O and SO2 conditions. The present invention is achieved through the following technical solutions: The present invention discloses a method for preparing an expandable graphite (EG) composite ferroferric oxide-supported platinum catalyst for CO catalytic oxidation under H2O and SO2 conditions. The Pt / Fe3O4 catalyst material is prepared by a coprecipitation method using soluble iron salt and platinum salt as main raw materials and alkali as a precipitant. In order to improve its hydrophobicity and sulfur resistance, the Pt / Fe3O4 catalyst is composited with expandable graphite (EG) by a mechanical grinding method to obtain an EG-Pt / Fe3O4 catalyst material. The specific preparation steps are as follows: Step 1: dissolve soluble iron salt in deionized water at a certain temperature and in a certain proportion; Step 2: adding soluble platinum salt and alkali solution into the above solution in a certain proportion respectively; Step 3: After the reaction is complete, the precipitate is washed, centrifuged, and dried overnight to obtain the Pt / Fe3O4 catalyst; Step 4: Mix and grind the Pt / Fe3O4 catalyst with a certain proportion of expandable graphite (EG) to obtain the EG-Pt / Fe3O4 catalyst; As a further improvement, the entire reaction process described in the present invention is carried out at a temperature of 80°C.

[0004] As a further improvement, the concentration of the alkali solution of the present invention is 1-3 mol·L -1 .

[0005] As a further improvement, the iron salt added in the present invention is ferrous sulfate or ferrous chloride.

[0006] As a further improvement, the molar ratio of the alkali contained in the alkali solution of the present invention to the iron salt is 3:1-5:1.

[0007] As a further improvement, the platinum salt added in the present invention is chloroplatinic acid, sodium chloroplatinate or potassium chloroplatinate.

[0008] As a further improvement, the loading amount of the precious metal described in the present invention is 0.1 wt%-0.5 wt%.

[0009] As a further improvement, the washing solvent of the present invention is deionized water, and the drying temperature is 80°C.

[0010] As a further improvement, the mass ratio of the added expandable graphite (EG) to Pt / Fe3O4 in the present invention is 1:5-1:20.

[0011] Positive effects of the present invention: The Pt / Fe3O4 catalyst material was prepared by coprecipitation method using soluble iron salt and platinum salt as the main raw materials and alkali as the precipitant. In order to improve its hydrophobicity and sulfur resistance, the Pt / Fe3O4 catalyst was compounded with expandable graphite (EG) by mechanical grinding to obtain the EG-Pt / Fe3O4 catalyst material. The preparation process is simple and convenient, the cost is low, the catalyst has high catalytic activity, high stability and wide applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is the X-ray diffraction pattern of the catalyst prepared in the embodiment provided by the present invention.

[0013] Figure 2 It is a graph of CO conversion rate of the catalyst prepared in the embodiment provided by the present invention.

[0014] Figure 3 It is the CO stability spectrum of the catalyst prepared in the example provided by the present invention.

[0015] Note: The gas composition is: 1% CO, 100 ppm SO2, 15% O2, the rest of the gas is N2, the catalyst dosage is 100 mg, and the space velocity is 30000 mL•g -1 •h -1 . Specific implementation methods The technical solution of the present invention is further described below by means of specific embodiments: Example

[0017] First, 8.34 g FeSO4·7H2O was dissolved in 100 mL deionized water to prepare 0.3 mol·L -1 FeSO4 solution and stirred at 80 °C for 30 min. -1 2 mL of sodium citrate was added to the above solution, followed by rapid injection of a certain amount of 0.1 mol·L -1 118.8 uL of H2PtCl6·6H2O, and then 2 mol·L -1 45 mL of NaOH was added to the above solution, and then stirred continuously for 2 h. After the reaction was completed, the precipitate was washed with deionized water, centrifuged, and dried at 80 °C overnight to obtain a Pt / Fe3O4 catalyst with a Pt loading of 0.1 wt%. Finally, expandable graphite (EG) and Pt / Fe3O4 catalyst were mixed and ground at a mass ratio of 1:10, wherein the mass fraction of expandable graphite (EG) was 0.1 wt%, and 0.1EG-0.1Pt / Fe3O4 catalyst was obtained. Example

[0018] The same operation as in Example 1 was used except that the iron salt was changed to 8.34 g FeSO4·7H2O and the platinum salt was changed to 0.1 mol·L -1 237.6 uL of Na2PtCl6, replace the base with KOH and prepare 1 mol·L -1 100 mL of KOH solution was added, and the mass ratio of the mixed grinding of expandable graphite (EG) and Pt / Fe3O4 catalyst was changed to 1:5, and the Pt loading in the catalyst was 0.2wt%. Example

[0019] The same operation as in Example 1 was used except that the iron salt was changed to 8.34 g FeSO4·7H2O and the platinum salt was changed to 0.1 mol·L -1 297 uL of K2PtCl6·6H2O, replace the base with NaOH and prepare 1.5 mol·L -1 80 mL of NaOH solution was added, and the mass ratio of the mixed grinding of expandable graphite (EG) and Pt / Fe3O4 catalyst was changed to 1:15, and the Pt loading in the catalyst was 0.25 wt%. Example

[0020] The same operation as in Example 1 was used except that the iron salt was changed to 3.81 g FeCl2 and the platinum salt was changed to 0.1 mol·L-1 356.4 uL of H2PtCl6·6H2O, replace the base with KOH and prepare 2 mol·L -1 The KOH solution of 65 mL was added, and the mixed grinding mass ratio of expandable graphite (EG) and Pt / Fe3O4 catalyst was changed to 1:10. The Pt loading in the catalyst was 0.3wt%. Example

[0021] The same operation as in Example 1 was used except that the iron salt was changed to 3.81 g FeCl2 and the platinum salt was changed to 0.1 mol·L -1 475.2 uL of Na2PtCl6, replace the base with NaOH, and prepare 2.5 mol·L -1 56 mL of NaOH solution was added, and the mass ratio of the mixed grinding of expandable graphite (EG) and Pt / Fe3O4 catalyst was changed to 1:20. The Pt loading in the catalyst was 0.4 wt%. Example

[0022] The same operation as in Example 1 was used except that the iron salt was changed to 3.81 g FeCl2 and the platinum salt was changed to 0.1 mol·L -1 594 uL of K2PtCl6, replace the base with KOH and prepare 3 mol·L -1 50 mL of KOH solution was added, and the mass ratio of the mixed grinding of expandable graphite (EG) and Pt / Fe3O4 catalyst was changed to 1:10, and the Pt loading in the catalyst was 0.5 wt%.

[0023] Finally, it should be noted that the above examples are only a few specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments, and there are many variations. All variations that can be directly derived or associated with the content disclosed by a person skilled in the art should be considered as the protection scope of the present invention.

Claims

1. A method for preparing expandable graphite (EG) composite ferroferric oxide supported platinum catalyst for catalytic oxidation of CO. The method is characterized by: The Pt / Fe3O4 catalyst material is prepared by co-precipitation method using soluble iron salt and platinum salt as the main raw materials and alkali as the precipitant. In order to improve its hydrophobicity and sulfur resistance, the Pt / Fe3O4 catalyst is compounded with expandable graphite (EG) by mechanical grinding to obtain the EG-Pt / Fe3O4 catalyst material. The specific preparation steps are as follows: Step 1: dissolve soluble iron salt in deionized water at a certain temperature and in a certain proportion; Step 2: adding soluble platinum salt and alkali solution into the above solution in a certain proportion respectively; Step 3: After the reaction is complete, the precipitate is washed, centrifuged, and dried overnight to obtain the Pt / Fe3O4 catalyst; Step 4: Mix and grind the Pt / Fe3O4 catalyst with a certain proportion of expandable graphite (EG) to obtain the EG-Pt / Fe3O4 catalyst.

2. The method for preparing a catalytic material for catalytic oxidation of CO under H2O and SO2 conditions according to claim 1, characterized in that: The entire reaction process is carried out at a temperature of 60-90°C.

3. The method for preparing a catalytic material for catalytic oxidation of CO under H2O and SO2 conditions according to claim 1, characterized in that: The alkali solution is NaOH or KOH.

4. The method for preparing a catalytic material for catalytic oxidation of CO under H2O and SO2 conditions according to claim 1, characterized in that: The concentration of the alkali solution is 1-3 mol·L -1 .

5. The method for preparing a catalytic material for catalytic oxidation of CO under H2O and SO2 conditions according to claim 1, characterized in that: The iron salt is ferrous sulfate or ferrous chloride.

6. The method for preparing a catalytic material for catalytic oxidation of CO under H2O and SO2 conditions according to claim 1, characterized in that: The molar ratio of the alkali contained in the alkali solution to the iron salt is 3:1-5:

1.

7. The method for preparing a catalytic material for catalytic oxidation of CO under H2O and SO2 conditions according to claim 1, characterized in that: The added platinum salt is chloroplatinic acid, sodium chloroplatinate or potassium chloroplatinate.

8. The method for preparing a catalytic material for catalytic oxidation of CO under H2O and SO2 conditions according to claim 1, characterized in that: The precious metal loading is 0.1 wt%-1.0 wt%.

9. The method for preparing a catalytic material for catalytic oxidation of CO under H2O and SO2 conditions according to claim 1, characterized in that: The mass ratio of the added expandable graphite (EG) to Pt / Fe3O4 is 1:5-1:

20.

10. Use of expandable graphite (EG) composite ferroferric oxide supported platinum catalyst prepared by the preparation method of claim 1 in catalytic oxidation of CO under H2O and SO2 conditions.

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