Surface hydrophobic method of efficient carbon monoxide selective oxidation catalyst

Abstract

The invention provides a surface hydrophobic method of an efficient carbon monoxide selective oxidation catalyst, which comprises the following steps: A) mixing stearic acid, an organic solvent, water and a carbon monoxide selective oxidation catalyst to obtain an initial hydrophobic catalyst; and B) washing and drying the initial hydrophobic catalyst to obtain the surface hydrophobic catalyst. According to the method, the stearic acid is dissolved in the organic solvent, then the carbon monoxide selective oxidation catalyst is treated in combination with a very small amount of deionized water, after treatment by the method, stearic acid molecules are stably combined on the surface of the catalyst in the form of R-O-Al, an R-O-Pt structure is not formed, Pt active sites can be reserved to the maximum extent, and high catalytic performance is obtained. The treatment method provided by the invention has the advantages of simple operation, easily available raw materials, high surface hydrophobic degree, small loss of catalyst performance and good stability.

Description

Technical Field

[0001] The invention belongs to the technical field of catalysts, and in particular relates to a surface hydrophobic method for a highly efficient carbon monoxide selective oxidation catalyst. Background Art

[0002] Since the beginning of the 21st century, the rapid development of human society has consumed a large amount of fossil fuels, thus bringing serious environmental problems. In addition, the non-renewable nature of fossil fuels has also made the energy shortage problem of mankind increasingly serious. Fuel cells are an efficient and environmentally friendly energy conversion device that can directly convert chemical energy stored in fuels and oxidants into electrical energy, and the energy conversion efficiency can reach more than 60%, which is much higher than the 30% of internal combustion engines, and there is no pollutant emission. Therefore, the power system and distributed energy supply system with fuel cells as the core are considered to be one of the most attractive forms of terminal energy utilization in the 21st century. Among them, proton exchange membrane fuel cells (PEMFC) have developed rapidly due to their advantages of low start-up temperature, low emissions, high energy efficiency and simple structure, but the materials of their working electrodes are mostly Pt metal, which is extremely sensitive to CO and is easily deactivated by CO poisoning. Therefore, pure hydrogen (CO content less than 0.2ppm) is usually required as fuel.

[0003] At present, most industrial hydrogen-rich gas is produced by methanol reforming. The hydrogen produced contains 0.5-2% CO, 10-20% water and 20% CO2 gas, which needs to be purified. In actual methanol fuel cell applications, since the hydrogen contains a large amount of water vapor, and the operating temperature of the fuel cell is usually low (80-200°C), a large amount of liquid water will be produced during operation and enter the carbon monoxide selective oxidation reactor with a lower temperature, causing water poisoning of the catalyst and leading to deactivation. Therefore, the surface hydrophobic treatment of the carbon monoxide selective oxidation catalyst is a key step for the methanol fuel cell to maintain a long-term stable power generation process. Pt / Fe-based catalysts have received widespread attention in the carbon monoxide selective oxidation system due to their excellent CO binding ability and high catalyst stability. The current Pt / Fe-based catalyst surface is mostly hydrophilic, and it is difficult to try to maintain efficient carbon monoxide selective oxidation activity under conditions of high water content and low reaction temperature.

[0004] The technical disadvantages of existing catalyst surface hydrophobicity are that the solvents are mostly easy-to-make poison reagents, which are highly dangerous and toxic. At the same time, the surface hydrophobic groups are unstable at temperatures above 100°C and are easily decomposed by heat, which has a great impact on the initial activity of the catalyst.

[0005] Therefore, it becomes a problem to be solved to provide a surface hydrophobic treatment method which is simple to operate, has readily available raw materials, has strong hydrophobic ability, and has little effect on the catalyst. Summary of the invention

[0006] In view of this, the technical problem to be solved by the present invention is to provide a surface hydrophobic method for an efficient carbon monoxide selective oxidation catalyst. The surface hydrophobic method provided by the present invention is simple to operate, has readily available raw materials, has strong hydrophobic ability, and has little effect on the catalyst.

[0007] The present invention provides a method for surface hydrophobicity of a highly efficient carbon monoxide selective oxidation catalyst, comprising the following steps:

[0008] A) mixing stearic acid, an organic solvent, water and a carbon monoxide selective oxidation catalyst to obtain an initial hydrophobic catalyst;

[0009] B) washing the initial hydrophobic catalyst and then drying it to obtain a surface hydrophobic catalyst.

[0010] Preferably, the organic solvent is selected from one or more of toluene, cyclohexane, methylcyclohexane, ether and acetone.

[0011] Preferably, the organic solvent is selected from methylcyclohexane and / or diethyl ether.

[0012] Preferably, the organic solvent is selected from methylcyclohexane.

[0013] Preferably, the mass ratio of the organic solvent to water is 1:(0.01-0.2), preferably 1:0.05.

[0014] Preferably, the mass ratio of stearic acid to organic solvent is (0.01-0.2):1, preferably 0.05:1.

[0015] Preferably, the carbon monoxide selective oxidation catalyst is selected from a Pt-based catalyst;

[0016] The ratio of the mass of the carbon monoxide selective oxidation catalyst to the total mass of stearic acid, organic solvent and water is (0.1-0.3):1, preferably 0.2:1.

[0017] Preferably, the mixing comprises:

[0018] The stearic acid, the organic solvent, the water and the carbon monoxide selective oxidation catalyst are ultrasonically mixed and then mixed and stirred;

[0019] The mixing and stirring is performed at a temperature of 25±5° C. for 4 to 24 hours, preferably 8 hours.

[0020] Preferably, the washing comprises suction filtration washing, and the suction filtration washing is performed using an organic extraction solvent, and the organic extraction solvent comprises one or more of anhydrous ethanol, acetone, and benzene, preferably anhydrous ethanol.

[0021] Preferably, the drying temperature is 60-140°C.

[0022] Compared with the prior art, the present invention provides a surface hydrophobic method for an efficient carbon monoxide selective oxidation catalyst, comprising the following steps: A) mixing stearic acid, an organic solvent, water and a carbon monoxide selective oxidation catalyst to obtain an initial hydrophobic catalyst; B) washing the initial hydrophobic catalyst and drying it to obtain a surface hydrophobic catalyst. The present invention selects an organic solvent to dissolve stearic acid and then combines a very small amount of deionized water to treat the carbon monoxide selective oxidation catalyst. After the method is treated, the stearic acid molecules are stably bound to the catalyst surface in the form of RO-Al, and no RO-Pt structure is formed, which can retain the Pt active sites to the maximum extent and obtain high catalytic performance. The treatment method provided by the present invention is simple to operate, the raw materials are easily available, the surface hydrophobicity is high, the catalyst performance loss is small, and the stability is good. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The surface water contact angle test results of the catalyst prepared in Example 1;

[0024] Figure 2 The results of catalyst stability test. DETAILED DESCRIPTION

[0025] The present invention provides a method for surface hydrophobicity of a highly efficient carbon monoxide selective oxidation catalyst, comprising the following steps:

[0026] A) mixing stearic acid, an organic solvent, water and a carbon monoxide selective oxidation catalyst to obtain an initial hydrophobic catalyst;

[0027] B) washing the initial hydrophobic catalyst and then drying it to obtain a surface hydrophobic catalyst.

[0028] The invention firstly mixes stearic acid, an organic solvent, water and a carbon monoxide selective oxidation catalyst to obtain an initial hydrophobic catalyst.

[0029] The present invention has no particular limitation on the mixing method, and any method known to those skilled in the art for uniformly mixing the raw materials can be used to mix the raw materials in the present invention. For example, the raw materials can be mixed by stirring or by ultrasound, or by a combination of two or more mixing methods.

[0030] Furthermore, the present invention has no particular restrictions on the mixing order of the raw materials. In some specific embodiments of the present invention, stearic acid and an organic solvent may be mixed to obtain a mixed solution, and then a carbon monoxide selective oxidation catalyst may be added to perform ultrasonic mixing, and then water may be added to perform mixing.

[0031] Among them, the ultrasonic power of ultrasonic mixing is 300W~1000W, and can be 300, 400, 500, 600, 700, 800, 900, 1000, or any value between 300W and 1000W, and the preferred power is 400W; the ultrasonic time is 15 to 40min, and can be 15, 20, 25, 30, 35, 40, or any value between 15 and 40min, and the preferred time is 30min.

[0032] Preferably, adding water for mixing is mixing and stirring, and the temperature of the mixing and stirring is 25±5° C. In the present invention, room temperature is defined as 25±5° C. The mixing and stirring time is 4 to 24 hours, which can be 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, or any value between 4 and 24 hours, preferably 8 hours.

[0033] In some other embodiments of the present invention, stearic acid, an organic solvent and water may be mixed first to obtain a precursor solution, wherein the mixing is preferably carried out by ultrasonic mixing, and the ultrasonic mixing time is preferably 30 minutes.

[0034] Then, the precursor solution and the carbon monoxide selective oxidation catalyst are ultrasonically mixed, wherein the ultrasonic power of the ultrasonic mixing is 300W to 1000W, which can be 300, 400, 500, 600, 700, 800, 900, 1000, or any value between 300W and 1000W, and the preferred power is 400W; the ultrasonic time is 15 to 40min, which can be 15, 20, 25, 30, 35, 40, or any value between 15 and 40min, and the preferred time is 30min.

[0035] After the ultrasonic mixing is completed, mixing and stirring are carried out at room temperature. The mixing and stirring time is 4 to 24 hours, which can be 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, or any value between 4 and 24 hours, preferably 8 hours.

[0036] Further, the organic solvent is selected from one or more of toluene, cyclohexane, methylcyclohexane, ether, and acetone. Preferably, the organic solvent is selected from methylcyclohexane and / or ether. Further preferably, the organic solvent is selected from methylcyclohexane.

[0037] The mass ratio of the organic solvent to water is 1:(0.01-0.2), and can be 1:0.01, 1:0.03, 1:0.05, 1:0.07, 1:0.09, 1:0.1, 1:0.11, 1:0.13, 1:0.15, 1:0.17, 1:0.19, 1:0.2, or any value between 1:(0.01-0.2), preferably 1:0.05.

[0038] The mass ratio of the stearic acid to the organic solvent is (0.01-0.2):1, and can be 0.01:1, 0.03:1, 0.05:1, 0.07:1, 0.09:1, 0.1:1, 0.11:1, 0.13:1, 0.15:1, 0.17:1, 0.19:1, 0.2:1, or any value between (0.01-0.2):1, preferably 0.05:1.

[0039] In the present invention, the carbon monoxide selective oxidation catalyst is selected from a Pt-based catalyst. The present invention has no special restrictions on the type and source of the Pt-based catalyst, which can be prepared by itself or a commercial product. Preferably, the Pt-based catalyst is selected from an alumina-supported Pt-based catalyst.

[0040] The ratio of the mass of the carbon monoxide selective oxidation catalyst to the total mass of stearic acid, organic solvent and water is (0.1-0.3):1, which can be 0.1:1, 0.15:1, 0.2:1, 0.25:1, 0.3:1, and the preferred ratio is 0.2:1.

[0041] After obtaining the initial hydrophobic catalyst, the initial hydrophobic catalyst is washed, wherein the washing includes suction filtration washing, and the suction filtration washing is performed using an organic extraction solvent, and the organic extraction solvent includes one or more of anhydrous ethanol, acetone, and benzene, preferably anhydrous ethanol.

[0042] Finally, the washed catalyst is dried at a temperature of 60-140°C, which may be 60, 70, 80, 90, 100, 110, 120, 130, 140, or any value between 60 and 140°C, preferably 100°C.

[0043] The treatment method provided by the invention is simple to operate, the raw materials are easily available, the surface hydrophobicity is high, the catalyst performance loss is small, and the stability is good.

[0044] The present invention also provides a surface hydrophobic catalyst obtained by the above treatment method. The surface water contact angle of the surface hydrophobic catalyst is 108° to 156°.

[0045] The present invention also provides an application of the surface hydrophobic catalyst in the elimination of carbon monoxide in a hydrogen purification system of a methanol reforming fuel cell.

[0046] In order to further understand the present invention, the surface hydrophobic method of the efficient carbon monoxide selective oxidation catalyst provided by the present invention is described below in conjunction with examples, and the protection scope of the present invention is not limited by the following examples.

[0047] The materials used in the following examples and comparative examples are all chemically pure. The Pt catalyst is selected from a Pt-based catalyst supported by alumina.

[0048] Embodiment 1:

[0049] The specific steps are as follows:

[0050] (1) Prepare a 5 wt% stearic acid / methylcyclohexane solution A, take 20 ml of the prepared solution A and add it to a beaker, stir at room temperature for 10 min, then add 4 g of Pt catalyst. Then transfer the solution to an ultrasonic reactor and treat it with ultrasound at a power of 400 W for 30 min, then add 1 ml of deionized water and stir at room temperature for 8 h to obtain a mixed solution B.

[0051] (2) The mixed solution B was filtered three times with anhydrous ethanol until the pH value was 7-9. The filtered product was transferred to a 100° C. forced air drying oven and dried for 8 h to obtain the final hydrophobic catalyst, which was recorded as P-MCH-1.

[0052] Embodiment 2:

[0053] The specific steps are as follows:

[0054] (1) Prepare a stearic acid / methylcyclohexane solution A with a mass concentration of 5 wt%, take 20 ml of the prepared solution A and add it to a beaker, stir at room temperature for 10 min, and then add 4 g of Pt catalyst. Then transfer the solution to an ultrasonic reactor and treat it with ultrasound at a power of 400 W for 30 min, then add 0.2 ml of deionized water and stir at room temperature for 8 h to obtain a mixed solution B.

[0055] (2) The mixed solution B was filtered three times with anhydrous ethanol until the pH value was 7-9. The filtered product was transferred to a 100°C forced air drying oven and dried for 8 hours to obtain the final hydrophobic catalyst, which was recorded as P-MCH-0.2.

[0056] Embodiment 3:

[0057] The specific steps are as follows:

[0058] (1) Prepare a stearic acid / methylcyclohexane solution A with a mass concentration of 5 wt%, take 20 ml of the prepared solution A and add it to a beaker, stir at room temperature for 10 min, and then add 4 g of Pt catalyst. Then transfer the solution to an ultrasonic reactor and treat it with ultrasound at a power of 400 W for 30 min, then add 2 ml of deionized water and stir at room temperature for 8 h to obtain a mixed solution B.

[0059] (2) The mixed solution B was filtered three times with anhydrous ethanol until the pH value was 7-9. The filtered product was transferred to a 100° C. forced air drying oven and dried for 8 h to obtain the final hydrophobic catalyst, which was recorded as P-MCH-2.

[0060] Embodiment 4:

[0061] The specific steps are as follows:

[0062] (1) Prepare a 5 wt% stearic acid / methylcyclohexane solution A, take 20 ml of the prepared solution A and add it to a beaker, stir at room temperature for 10 min, and then add 4 g of Pt catalyst. Then transfer the solution to an ultrasonic reactor and treat it with ultrasound at a power of 400 W for 30 min, then add 4 ml of deionized water and stir at room temperature for 8 h to obtain a mixed solution B.

[0063] (2) The mixed solution B was filtered three times with anhydrous ethanol until the pH value was 7-9. The filtered product was transferred to a 100° C. forced air drying oven and dried for 8 h to obtain the final hydrophobic catalyst, which was recorded as P-MCH-4.

[0064] Embodiment 5:

[0065] The specific steps are as follows:

[0066] (1) Prepare a stearic acid / ether solution A with a mass concentration of 5 wt%, take 20 ml of the prepared solution A and add it to a beaker, stir at room temperature for 10 min, add 1 ml of deionized water, and then add 4 g of Pt catalyst. Then transfer the solution to an ultrasonic reactor and treat it with ultrasound at a power of 400 W for 30 min, and stir at room temperature for 8 h to obtain a mixed solution B.

[0067] (2) The mixed solution B was filtered three times with anhydrous ethanol until the pH value was 7-9. The filtered product was transferred to a 100°C forced air drying oven and dried for 8 hours to obtain the final hydrophobic catalyst, which was recorded as P-Et2O-1.

[0068] Embodiment 6:

[0069] The specific steps are as follows:

[0070] (1) Prepare a stearic acid / toluene solution A with a mass concentration of 5 wt%, take 20 ml of the prepared solution A and add it to a beaker, stir at room temperature for 10 min, add 1 ml of deionized water, and then add 4 g of Pt catalyst. Then transfer the solution to an ultrasonic reactor and perform ultrasonic treatment at a power of 400 W for 30 min, and stir at room temperature for 8 h to obtain a mixed solution B.

[0071] (2) The mixed solution B was filtered three times with anhydrous ethanol until the pH value was 7-9. The filtered product was transferred to a 100°C forced air drying oven and dried for 8 hours to obtain the final hydrophobic catalyst, which was recorded as P-MB-1.

[0072] Embodiment 7:

[0073] The specific steps are as follows:

[0074] (1) Prepare a stearic acid / cyclohexane solution A with a mass concentration of 5 wt%, take 20 ml of the prepared solution A and add it to a beaker, stir at room temperature for 10 min, add 1 ml of deionized water, and then add 4 g of Pt catalyst. Then transfer the solution to an ultrasonic reactor and perform ultrasonic treatment at a power of 400 W for 30 min, and stir at room temperature for 8 h to obtain a mixed solution B.

[0075] (2) The mixed solution B was filtered three times with anhydrous ethanol until the pH value was 7-9. The filtered product was transferred to a 100°C forced air drying oven and dried for 8 hours to obtain the final hydrophobic catalyst, which was recorded as P-HEX-1.

[0076] Embodiment 8:

[0077] The specific steps are as follows:

[0078] (1) Prepare a stearic acid / acetone solution A with a mass concentration of 5 wt%, take 20 ml of the prepared solution A and add it to a beaker, stir at room temperature for 10 min, add 1 ml of deionized water, and then add 4 g of Pt catalyst. Then transfer the solution to an ultrasonic reactor and treat it with ultrasound at a power of 400 W for 30 min, and stir at room temperature for 8 h to obtain a mixed solution B.

[0079] (2) The mixed solution B was filtered three times with anhydrous ethanol until the pH value was 7-9. The filtered product was transferred to a 100°C forced air drying oven and dried for 8 hours to obtain the final hydrophobic catalyst, which was recorded as P-AC-1.

[0080] Comparative Example 1:

[0081] The specific steps are as follows:

[0082] (1) Prepare a stearic acid / methylcyclohexane solution A with a mass concentration of 5 wt%, take 20 ml of the prepared solution A and add it to a beaker, stir at room temperature for 10 min, and then add 4 g of Pt catalyst. Then transfer the solution to an ultrasonic reactor and treat it with ultrasound at a power of 400 W for 30 min, and stir at room temperature for 8 h to obtain a mixed solution B.

[0083] (2) The mixed solution B was filtered three times with anhydrous ethanol until the pH value was 7-9. The filtered product was transferred to a 100° C. forced air drying oven and dried for 8 h to obtain the final hydrophobic catalyst, which was recorded as P-MCH-0.

[0084] Comparative Example 2:

[0085] The specific steps are as follows:

[0086] (1) Prepare a stearic acid / ether solution A with a mass concentration of 5 wt%, take 20 ml of the prepared solution A and add it to a beaker, stir at room temperature for 10 min, and then add 4 g of Pt catalyst. Then transfer the solution to an ultrasonic reactor and treat it with ultrasound at a power of 400 W for 30 min, and stir at room temperature for 8 h to obtain a mixed solution B.

[0087] (2) The mixed solution B was filtered three times with anhydrous ethanol until the pH value was 7-9. The filtered product was transferred to a 100°C forced air drying oven and dried for 8 hours to obtain the final hydrophobic catalyst, which was recorded as P-Et2O-0.

[0088] Comparative Example 3:

[0089] The specific steps are as follows:

[0090] (1) Prepare a stearic acid / toluene solution A with a mass concentration of 5 wt%, take 20 ml of the prepared solution A and add it to a beaker, stir at room temperature for 10 min, and then add 4 g of Pt catalyst. Then transfer the solution to an ultrasonic reactor and treat it with ultrasound at a power of 400 W for 30 min, and stir at room temperature for 8 h to obtain a mixed solution B.

[0091] (2) The mixed solution B was filtered three times with anhydrous ethanol until the pH value was 7-9. The filtered product was transferred to a 100°C forced air drying oven and dried for 8 hours to obtain the final hydrophobic catalyst, which was recorded as P-MB-0.

[0092] Comparative Example 4:

[0093] The specific steps are as follows:

[0094] (1) Prepare a stearic acid / cyclohexane solution A with a mass concentration of 5 wt%, take 20 ml of the prepared solution A and add it to a beaker, stir at room temperature for 10 min, and then add 4 g of Pt catalyst. Then transfer the solution to an ultrasonic reactor and treat it with ultrasound at a power of 400 W for 30 min, and stir at room temperature for 8 h to obtain a mixed solution B.

[0095] (2) The mixed solution B was filtered three times with anhydrous ethanol until the pH value was 7-9. The filtered product was transferred to a 100°C forced air drying oven and dried for 8 hours to obtain the final hydrophobic catalyst, which was recorded as P-HEX-0.

[0096] Comparative Example 5:

[0097] The specific steps are as follows:

[0098] (1) Prepare a stearic acid / acetone solution A with a mass concentration of 5 wt%, take 20 ml of the prepared solution A and add it to a beaker, stir at room temperature for 10 min, and then add 4 g of Pt catalyst. Then transfer the solution to an ultrasonic reactor and treat it with ultrasound at a power of 400 W for 30 min, and stir at room temperature for 8 h to obtain a mixed solution B.

[0099] (2) The mixed solution B was filtered three times with anhydrous ethanol until the pH value was 7-9. The filtered product was transferred to a 100°C forced air drying oven and dried for 8 hours to obtain the final hydrophobic catalyst, which was recorded as P-AC-0.

[0100] Comparative Example 6:

[0101] The specific steps are as follows:

[0102] The catalyst of Comparative Example 6 is the original Pt catalyst without any hydrophobic treatment.

[0103] Experimental Example 1

[0104] A certain amount of catalyst was placed in a constant temperature section of a fixed bed reactor with an inner diameter of 7 mm, and the surface water contact angle test of the catalysts prepared in Examples 1-8 of the present application and Comparative Examples 1-5 was performed to verify the hydrophobicity of the catalysts. The results are shown in Tables 1 and Figure 1 , Figure 1 The surface water contact angle test results of the catalyst prepared in Example 1.

[0105] Table 1

[0106]

[0107]

[0108] Experimental Example 2

[0109] 0.3 g of the catalysts of Example 1 and Comparative Example 6 were placed in a constant temperature section of a fixed bed reactor with an inner diameter of 7 mm, and the catalysts prepared in Example 1 and Comparative Example 6 of the present application were continuously tested. The results are shown in FIG. Figure 2 , Figure 2 The results of the catalyst stability test are as follows: H2:CO:O2:H2O:CO2=60:1:1:18:20. The test temperature is 100°C and the mass space velocity is 10000 ml / g / h.

[0110] Depend on Figure 2 It can be seen that after 85 hours of catalysis, the carbon monoxide elimination rate of the catalyst provided in Comparative Example 6 dropped to 39.2%, while after 97 hours of catalysis, the carbon monoxide elimination rate of the catalyst provided in Example 1 remained 100%.

[0111] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for surface hydrophobicity of an efficient carbon monoxide selective oxidation catalyst, characterized in that: The following steps are involved: A) mixing stearic acid, an organic solvent, water and a carbon monoxide selective oxidation catalyst to obtain an initial hydrophobic catalyst; B) washing the initial hydrophobic catalyst and then drying it to obtain a surface hydrophobic catalyst.

2. The surface hydrophobic method according to claim 1, characterized in that: The organic solvent is selected from one or more of toluene, cyclohexane, methylcyclohexane, ether and acetone.

3. The surface hydrophobic method according to claim 1, characterized in that: The organic solvent is selected from methylcyclohexane and / or diethyl ether.

4. The surface hydrophobic method according to claim 1, characterized in that: The organic solvent is selected from methylcyclohexane.

5. The surface hydrophobic method according to claim 1, characterized in that: The mass ratio of the organic solvent to water is 1:(0.01-0.2), preferably 1:0.

05.

6. The surface hydrophobic method according to claim 1, characterized in that: The mass ratio of the stearic acid to the organic solvent is (0.01-0.2):1, preferably 0.05:

1.

7. The surface hydrophobic method according to claim 1, characterized in that: The carbon monoxide selective oxidation catalyst is selected from a Pt-based catalyst; The ratio of the mass of the carbon monoxide selective oxidation catalyst to the total mass of stearic acid, organic solvent and water is (0.1-0.3):1, preferably 0.2:

1.

8. The surface hydrophobic method according to claim 1, characterized in that: The mixing includes: The stearic acid, the organic solvent, the water and the carbon monoxide selective oxidation catalyst are ultrasonically mixed and then mixed and stirred; The mixing and stirring is performed at a temperature of 25±5° C. for 4 to 24 hours, preferably 8 hours.

9. The surface hydrophobic method according to claim 1, characterized in that: The washing includes suction filtration washing, and the suction filtration washing is performed using an organic extraction solvent. The organic extraction solvent includes one or more of anhydrous ethanol, acetone, and benzene, preferably anhydrous ethanol.

10. The surface hydrophobic method according to claim 1, characterized in that: The drying temperature is 60-140°C.

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