Preparation method of porous platinum powder

Abstract

The invention provides a preparation method of porous platinum powder, which is characterized by comprising the following steps: (1) immersing a platinum sheet in a hydrochloric acid solution, mixing with an oxidizing agent, heating and boiling until the platinum sheet is completely dissolved, and sequentially cooling and filtering for the first time to obtain a platinum-containing filtrate; (2) heating the platinum-containing filtrate obtained in the step (1), mixing the platinum-containing filtrate with a platinum precipitant, and sequentially carrying out secondary filtration, primary washing and drying treatment to obtain platinum salt powder; and (3) mixing the reduced mixed solution and the platinum salt powder obtained in the step (2) under a stirring condition, and then sequentially standing, filtering for the third time, washing for the second time, ultrasonically cleaning and drying to obtain the porous platinum powder. The porous platinum powder obtained by adopting the preparation method provided by the invention is relatively large in specific surface area, so that the platinum powder has relatively high reaction activity and gas adsorption capacity; in addition, the preparation method is relatively friendly to health and environment.

Description

Technical Field

[0001] The invention belongs to the field of precious metal powder manufacturing, relates to platinum powder, and in particular to a method for preparing porous platinum powder. Background Art

[0002] In modern industry and new technology industries, platinum group metals have extremely wide applications due to their superior physical and chemical properties. Among them, platinum has high chemical stability and catalytic activity, and has important applications in medicine, semiconductor devices, integrated circuits, and precision alloys. The application of platinum alloys as coating materials has greatly promoted the development of the aerospace industry. High-purity platinum is widely used in defense, military industry, electronics industry and other fields.

[0003] Platinum powder has excellent catalytic activity and stability. It is used as a high-performance antioxidant. It is safe, environmentally friendly, and non-toxic. It is widely used in the fields of biomedicine, beauty and health care. Platinum powder is used as the conductive component of thick film slurries in the electronics industry, and as the conductive component of highly stable, highly reliable, and excellent-performance conductive slurries and electrode slurries in microelectronics technology.

[0004] A lot of research has been conducted on the preparation of precious metal powders and their alloys at home and abroad. At present, the particle size of powders manufactured by physical methods is often as high as tens of microns, and the shape is irregular, which is not suitable for the manufacture of micro components with small volume and thin printing layer requirements. For example, CN 111774578A discloses a method for preparing micron-level platinum powder. This method can obtain platinum powder with a particle size of about 20μm through smelting, bottom casting, cutting, pulse discharge powder making, black removal, and screening. Screening is required to remove powders with special shapes. The platinum powder product prepared by physical methods does not have a porous structure. For example, CN 104550999A discloses a method for preparing submicron honeycomb platinum powder by chemical reduction. This method is to dissolve platinum salt in a dispersant system, then add a reducing agent to reduce the platinum powder, and vacuum dry it, so as to controllably obtain honeycomb platinum powder with a particle size between 40 and 480nm. However, nano-scale platinum powder is difficult to disperse when preparing the slurry, shrinks severely during sintering, and is prone to defects such as pores and cracks. It is difficult to form a dense coating with the binding phase, which seriously affects the electrical and mechanical properties of the component.

[0005] In addition, the specific surface area of ​​the platinum powder provided by the above patent is relatively low and cannot meet the demand for platinum powder in special circumstances; therefore, it is necessary to provide a platinum powder with a large specific surface area. Summary of the invention

[0006] The object of the present invention is to provide a method for preparing porous platinum powder, wherein the porous platinum powder has a large specific surface area, high reaction activity and strong gas adsorption capacity.

[0007] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0008] The present invention provides a method for preparing porous platinum powder, the preparation method comprising the following steps:

[0009] (1) immersing a platinum flake in a hydrochloric acid solution, then mixing an oxidant, heating and boiling until the platinum flake is completely dissolved, and then cooling and filtering once to obtain a platinum-containing filtrate;

[0010] (2) heating the platinum-containing filtrate obtained in step (1) and mixing it with a platinum precipitant, and then performing a second filtration, a first washing and a drying treatment in sequence to obtain a platinum salt powder;

[0011] (3) adding the platinum salt powder obtained in step (2) to the reducing mixed solution under stirring conditions, and then sequentially allowing to stand, filtering three times, washing twice, ultrasonically cleaning, and drying to obtain the porous platinum powder.

[0012] In the present invention, porous platinum powder with a large specific surface area is prepared by sequentially performing platinum liquid preparation, platinum salt powder preparation, platinum salt powder reduction and post-treatment processes, so that the platinum powder has higher reaction activity and gas adsorption capacity.

[0013] In addition, the present invention achieves the dissolution of platinum flakes by mixing hydrochloric acid and an oxidant, and then obtains platinum salt powder by simple impurity removal and drying treatment; the platinum salt powder contains ammonium chloroplatinate and potassium chloroplatinate; and then the principle of reducing the platinum salt powder by mixing a reduction mixed solution is that the powdered platinum salt is added to the reduction mixed solution, the reducing agent is excessive, and the powdered platinum salt is quickly consumed. The platinum salt is quickly reduced to metal, and a large amount of gas is generated during the reduction reaction process. The escape of the gas causes a large number of openings or through holes in the metal particles, thereby obtaining a platinum powder with a porous structure.

[0014] As a preferred technical solution of the present invention, the thickness of the platinum sheet in step (1) is 0.05-0.3 mm, for example, 0.05 mm, 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm or 0.3 mm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0015] Preferably, the purity of the platinum flakes in step (1) is ≥99.9wt%, for example, it can be 99.9wt%, 99.92wt%, 99.94wt%, 99.96wt% or 99.98wt%, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0016] As a preferred technical solution of the present invention, the concentration of the hydrochloric acid solution in step (1) is 10 to 38 wt%, for example, it can be 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt% or 38 wt%, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0017] In the present invention, the function of the hydrochloric acid solution is: concentrated hydrochloric acid reacts with an oxidant to generate active chlorine, and the active chlorine is used to accelerate the dissolution of the platinum flakes; if the concentration of the hydrochloric acid solution is too low, the dissolution efficiency will be low.

[0018] Preferably, the oxidant in step (1) comprises any one of potassium chlorate, sodium chlorate, hydrogen peroxide or chlorine, or a combination of at least two of them. Typical but non-limiting combinations include: a combination of potassium chlorate, sodium chlorate and hydrogen peroxide, a combination of hydrogen peroxide and chlorine, a combination of potassium chlorate, sodium chlorate and chlorine, or a combination of potassium chlorate, sodium chlorate, hydrogen peroxide and chlorine.

[0019] Preferably, the mass ratio of the oxidant to the platinum flakes in step (1) is 0.8 to 3:1, for example, 0.8:1, 1:1, 1.4:, 1.8:1, 2.2:1, 2.6:1 or 3:1, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0020] As a preferred technical solution of the present invention, the terminal temperature of the heating in step (2) is 60-100°C, for example, it can be 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C or 100°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0021] In the present invention, the purpose of heating the platinum-containing filtrate in step (1) is to improve the selective precipitation of platinum. If the terminal temperature of the heating is too low, the yield of platinum will be low. If the terminal temperature is too high, it is necessary to increase the temperature by pressurization, which will cause the gas in the reaction system to leak out, and there is a risk of safety accidents.

[0022] Preferably, the platinum precipitant in step (2) comprises any one of ammonia water, potassium hydroxide, ammonium chloride or potassium chloride, or a combination of at least two thereof. Typical but non-limiting combinations include: a combination of ammonia water and ammonium chloride, a combination of potassium hydroxide and potassium chloride, a combination of ammonia water and potassium hydroxide, a combination of ammonium chloride and potassium chloride, or a combination of ammonia water, potassium hydroxide, ammonium chloride and potassium chloride.

[0023] Preferably, the mass ratio of the platinum precipitant to the platinum flakes is 0.5 to 4:1, for example, 0.5:1, 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1 or 4:1, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0024] In the present invention, the role of the platinum precipitant is to precipitate the platinum element in the platinum-containing filtrate to obtain a platinum precipitate. If the amount of the platinum precipitant is too much, the salt content in the system will increase, which is not conducive to the subsequent solid-liquid separation. If the amount is too little, the yield of platinum will be reduced.

[0025] As a preferred technical solution of the present invention, the washing liquid used for the one washing in step (2) includes any one of sodium chloride solution, ammonium chloride solution or potassium chloride solution, or a combination of at least two of them. Typical but non-limiting combinations include: a combination of sodium chloride solution and ammonium chloride solution, a combination of sodium chloride solution and potassium chloride solution, a combination of ammonium chloride solution and potassium chloride solution, or a combination of sodium chloride solution, ammonium chloride solution and potassium chloride solution.

[0026] Preferably, the number of washings in step (2) is 3 to 5 times, for example, 3 times, 4 times or 5 times.

[0027] Preferably, the temperature of the drying treatment in step (2) is 80-180°C, for example, 80°C, 100°C, 120°C, 140°C, 160°C or 180°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0028] Preferably, the drying time in step (2) is 1 to 16 hours, for example, 1 hour, 2 hours, 4 hours, 6 hours, 8 hours, 10 hours, 12 hours, 14 hours or 16 hours, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0029] As a preferred technical solution of the present invention, the reducing mixed solution in step (3) comprises deionized water and a reducing agent.

[0030] Preferably, the temperature of the deionized water is 80-100°C, for example, 80°C, 84°C, 88°C, 92°C, 96°C or 100°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0031] Preferably, the reducing agent comprises hydrazine hydrate.

[0032] Preferably, the content of the reducing agent in the reducing mixed solution is 1 to 30 wt%, for example, it can be 1 wt%, 4 wt%, 8 wt%, 12 wt%, 16 wt%, 20 wt%, 24 wt%, 28 wt% or 30 wt%, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0033] As a preferred technical solution of the present invention, the stirring speed in step (3) is 70 to 180 r / min, for example, it can be 70 r / min, 80 r / min, 100 r / min, 120 r / min, 140 r / min, 160 r / min or 180 r / min, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0034] In the present invention, the end point of the stirring is: the reaction solution in the reaction system is clear and transparent.

[0035] As a preferred technical solution of the present invention, the washing liquid used for the secondary washing in step (3) includes deionized water.

[0036] Preferably, the number of secondary washings in step (3) is 3 to 5 times, for example, 3 times, 4 times or 5 times.

[0037] As a preferred technical solution of the present invention, the power of the ultrasonic cleaning in step (3) is 100-800 W, for example, it can be 100 W, 200 W, 300 W, 400 W, 500 W, 600 W, 700 W or 800 W, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0038] Preferably, the drying temperature in step (3) is 80-180°C, for example, 80°C, 100°C, 120°C, 140°C, 160°C or 180°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0039] Preferably, the drying time in step (3) is 1 to 36 hours, for example, it can be 1 hour, 4 hours, 8 hours, 12 hours, 16 hours, 20 hours, 24 hours, 28 hours, 32 hours or 36 hours, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0040] As a preferred technical solution of the present invention, the method for preparing the porous platinum powder provided by the present invention comprises the following steps:

[0041] (1) immersing a platinum sheet having a thickness of 0.05 to 0.3 mm in a hydrochloric acid solution having a concentration of 10 to 37 wt %, and then mixing an oxidant, heating and boiling until the platinum sheet is completely dissolved, and then cooling and filtering once to obtain a platinum-containing filtrate;

[0042] Wherein, the mass ratio of the oxidant to the platinum flakes is 0.8 to 3:1;

[0043] (2) heating the platinum-containing filtrate obtained in step (1) to 60-100° C., mixing with a platinum precipitant, and then filtering twice, washing once 3-5 times, and drying at 80-180° C. for 1-16 hours to obtain a platinum salt powder;

[0044] Wherein, the mass ratio of the platinum precipitant to the platinum flakes is 0.5 to 4:1;

[0045] (3) adding the platinum salt powder obtained in step (2) to the mixed reduction solution under stirring at a speed of 70 to 180 r / min, and then sequentially standing, filtering three times, washing twice with deionized water for 3 to 5 times, ultrasonically cleaning, and drying to obtain the porous platinum powder;

[0046] The reducing mixed solution comprises deionized water at a temperature of 80 to 100° C. and a reducing agent; the content of the reducing agent is 1 to 30 wt %;

[0047] The power of the ultrasonic cleaning is 100-800W; the temperature of the drying is 80-180°C, and the time is 1-36h.

[0048] The numerical range described in the present invention not only includes the point values ​​listed above, but also includes any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0049] Compared with the prior art, the present invention has the following beneficial effects:

[0050] (1) The method for preparing the porous platinum powder provided by the present invention has simple operation steps, mild condition control, low energy consumption, and proper control during the preparation process, so that no other toxic and harmful substances escape from the system, which is relatively friendly to health and the environment, and the yield of platinum powder is high;

[0051] (2) The porous platinum powder obtained by the preparation method provided by the present invention has a larger specific surface area, so that the platinum powder has higher reactivity and gas adsorption capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 This is a scanning electron microscope image of the porous platinum powder provided in Example 1 of the present invention;

[0053] Figure 2 This is a scanning electron microscope image of the porous platinum powder provided in Example 2 of the present invention;

[0054] Figure 3 This is a scanning electron microscope image of the porous platinum powder provided in Example 3 of the present invention.

[0055] Figure 4 This is a scanning electron microscope image of the porous platinum powder provided in Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0056] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0057] Example 1

[0058] This embodiment provides a method for preparing porous platinum powder, the preparation method comprising the following steps:

[0059] (1) immersing a platinum sheet having a thickness of 0.05 mm in a hydrochloric acid solution having a concentration of 38 wt %, and then mixing an oxidant, heating and boiling until the platinum sheet is completely dissolved, and then cooling and filtering once to obtain a platinum-containing filtrate;

[0060] Wherein, the mass ratio of the oxidant to the platinum flakes is 0.8:1;

[0061] (2) heating the platinum-containing filtrate obtained in step (1) to 80° C. and then mixing with potassium hydroxide, followed by secondary filtration, three washes with 10 wt % potassium chloride, and drying at 80° C. for 8 h to obtain a platinum salt powder;

[0062] Wherein, the mass ratio of potassium hydroxide to platinum flakes is 0.5:1;

[0063] (3) adding the platinum salt powder obtained in step (2) to the reducing mixed solution under stirring at a speed of 180 r / min, and then sequentially allowing to stand, filtering three times, washing twice with deionized water for 3 to 5 times, ultrasonically cleaning, and drying to obtain the porous platinum powder;

[0064] Wherein, the reducing mixed solution comprises deionized water at a temperature of 100° C. and hydrazine hydrate; the content of the hydrazine hydrate is 30 wt %;

[0065] The power of the ultrasonic cleaning is 450W; the temperature of the drying is 150°C and the time is 24h.

[0066] The scanning electron microscope image of the porous platinum powder obtained in this example is as follows: Figure 1 shown.

[0067] Example 2

[0068] This embodiment provides a method for preparing porous platinum powder, the preparation method comprising the following steps:

[0069] (1) immersing a platinum sheet having a thickness of 0.15 mm in a hydrochloric acid solution having a concentration of 10 wt %, and then mixing with sodium chlorate, heating and boiling until the platinum sheet is completely dissolved, and then cooling and filtering once to obtain a platinum-containing filtrate;

[0070] Wherein, the mass ratio of the oxidant to the platinum flakes is 3:1;

[0071] (2) heating the platinum-containing filtrate obtained in step (1) to 60° C. and then mixing with ammonium chloride, followed by secondary filtration, three washes with 15 wt % ammonium chloride, and drying at 80° C. for 16 h to obtain a platinum salt powder;

[0072] Wherein, the mass ratio of the ammonium chloride to the platinum flakes is 2:1;

[0073] (3) adding the platinum salt powder obtained in step (2) to the reducing mixed solution under stirring at a speed of 70 r / min, and then sequentially allowing to stand, filtering three times, washing twice with deionized water for 3 to 5 times, ultrasonically cleaning, and drying to obtain the porous platinum powder;

[0074] Wherein, the reducing mixed solution comprises deionized water at a temperature of 80° C. and hydrazine hydrate; the content of the hydrazine hydrate is 10 wt %;

[0075] The power of the ultrasonic cleaning is 100W; the temperature of the drying is 180°C and the time is 5h.

[0076] The scanning electron microscope image of the porous platinum powder obtained in this example is as follows: Figure 2 shown.

[0077] Example 3

[0078] This embodiment provides a method for preparing porous platinum powder, the preparation method comprising the following steps:

[0079] (1) immersing a platinum sheet having a thickness of 0.3 mm in a hydrochloric acid solution having a concentration of 25 wt %, and then mixing with chlorine gas, heating and boiling until the platinum sheet is completely dissolved, and then cooling and filtering once to obtain a platinum-containing filtrate;

[0080] Wherein, the mass ratio of the oxidant to the platinum flakes is 2.5:1;

[0081] (2) heating the platinum-containing filtrate obtained in step (1) to 100° C. and then mixing with ammonia water, followed by secondary filtration, five washes with 15 wt % ammonium chloride, and drying at 150° C. for 5 h to obtain a platinum salt powder;

[0082] Wherein, the mass ratio of the ammonium chloride to the platinum flakes is 2:1;

[0083] (3) adding the platinum salt powder obtained in step (2) to the reducing mixed solution under stirring at a speed of 120 r / min, and then sequentially allowing to stand, filtering three times, washing twice with deionized water three times, ultrasonically cleaning, and drying to obtain the porous platinum powder;

[0084] Wherein, the reducing mixed solution comprises deionized water at a temperature of 90° C. and hydrazine hydrate; the content of the hydrazine hydrate is 1 wt%;

[0085] The power of the ultrasonic cleaning is 800W; the temperature of the drying is 80°C and the time is 36h.

[0086] The scanning electron microscope image of the porous platinum powder obtained in this example is as follows: Figure 3 shown.

[0087] Example 4

[0088] This embodiment provides a method for preparing porous platinum powder, which differs from the preparation method in Embodiment 1 only in that:

[0089] In this embodiment, the hydrochloric acid solution in step (1) is adjusted to a sulfuric acid solution with a concentration of 38 wt%.

[0090] Example 5

[0091] This embodiment provides a method for preparing porous platinum powder, which differs from the preparation method in Embodiment 1 only in that:

[0092] In this embodiment, the concentration of the hydrochloric acid solution in step (1) is adjusted to 5 wt %.

[0093] Example 6

[0094] This embodiment provides a method for preparing porous platinum powder, which differs from the preparation method in Embodiment 1 only in that:

[0095] In this embodiment, the terminal temperature of the heating in step (2) is adjusted to 50°C.

[0096] Example 7

[0097] This embodiment provides a method for preparing porous platinum powder, which differs from the preparation method in Embodiment 1 only in that:

[0098] In this embodiment, the temperature of the deionized water in the reducing mixed solution in step (3) is adjusted to 25°C.

[0099] Example 8

[0100] This embodiment provides a method for preparing porous platinum powder, which differs from the preparation method in Embodiment 1 only in that:

[0101] In this embodiment, the content of the reducing agent in the reducing mixed solution in step (3) is adjusted to 0.5 wt %.

[0102] Example 9

[0103] This embodiment provides a method for preparing porous platinum powder, which differs from the preparation method in Embodiment 1 only in that:

[0104] In this embodiment, the content of the reducing agent in the reducing mixed solution in step (3) is adjusted to 35 wt %.

[0105] Comparative Example 1

[0106] This comparative example provides a method for preparing porous platinum powder, which differs from Example 1 only in that:

[0107] In this comparative example, step (3) is adjusted as follows: after slurrying the platinum salt powder obtained in step (2) with water, the reducing mixed solution is added under stirring.

[0108] The scanning electron microscope image of the porous platinum powder provided in this comparative example is as follows Figure 4 shown.

[0109] Comparative Example 2

[0110] This comparative example provides a method for preparing porous platinum powder, which differs from Example 1 only in that:

[0111] In this comparative example, step (3) is adjusted as follows: mixing the reduction mixed solution and the platinum salt powder obtained in step (2) and then stirring.

[0112] The particle size and specific surface area of ​​the porous platinum powder provided in the above examples and comparative examples were measured, and the results are shown in Table 1.

[0113] Table 1

[0114]

[0115]

[0116] According to Table 1, we can know the following points:

[0117] (1) Comprehensive analysis of Examples 1-3 shows that the preparation method provided by the present invention can obtain porous platinum powder with a higher specific surface area and a higher direct yield of platinum;

[0118] (2) Comprehensive analysis of Example 1 and Examples 4-6 shows that the selection of the hydrochloric acid solution in step (1) and the end point temperature of the heating in step (2) will affect the specific surface area of ​​the porous platinum powder and the yield of the platinum powder;

[0119] If the hydrochloric acid solution is adjusted to a sulfuric acid solution, the platinum sheet will be difficult to dissolve, and the subsequent preparation of platinum powder will be impossible; if the concentration of the hydrochloric acid solution is too low, the dissolution rate of the platinum sheet will be slow, the dissolution efficiency will be reduced, and the yield of platinum powder will be low;

[0120] If the terminal temperature of the heating in step (2) is too low, the yield of the platinum element will be reduced;

[0121] (3) Comprehensive analysis of Example 1 and Examples 7-9 shows that in the reduction mixed solution, when the deionized water is at room temperature, the reduction reaction will be weak, the gas generated in the early stage of reduction is small, and it is difficult to generate porous platinum powder;

[0122] When the content of the reducing agent in the reducing mixed solution is too high, the reduction reaction will be violent and uncontrollable. If the content is too low, the reduction of the platinum powder will not be complete and porous platinum powder with a high specific surface area cannot be generated.

[0123] (4) Comprehensive analysis of the scanning electron microscope images of the platinum powder obtained in Example 1 and Comparative Example 1 shows that the mixing method of the platinum salt powder and the reducing mixed solution will affect the structure of the obtained platinum powder;

[0124] In addition, when in step (3): the reducing mixed solution and the platinum salt powder obtained in step (2) are mixed and then stirred (Comparative Example 2), the reducing agent and the reduced agent are directly contacted in large quantities and stirred to fully mix the two reactants, which will lead to a violent reaction, making the reaction uncontrolled and the product easily overflowing from the container, resulting in a decrease in the yield of platinum powder.

[0125] In summary, the porous platinum powder obtained by the preparation method provided by the present invention has a larger specific surface area, so that the platinum powder has higher reactivity and gas adsorption capacity; and it is more friendly to health and the environment.

[0126] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing porous platinum powder, characterized in that: The preparation method comprises the following steps: (1) immersing a platinum flake in a hydrochloric acid solution, then mixing an oxidant, heating and boiling until the platinum flake is completely dissolved, and then cooling and filtering once to obtain a platinum-containing filtrate; (2) heating the platinum-containing filtrate obtained in step (1) and mixing it with a platinum precipitant, and then performing a second filtration, a first washing and a drying treatment in sequence to obtain a platinum salt powder; (3) adding the platinum salt powder obtained in step (2) to the reducing mixed solution under stirring conditions, and then sequentially allowing to stand, filtering three times, washing twice, ultrasonically cleaning, and drying to obtain the porous platinum powder.

2. The preparation method according to claim 1, characterized in that: The thickness of the platinum sheet in step (1) is 0.05 to 0.3 mm; Preferably, the purity of the platinum flakes in step (1) is ≥99.9wt%.

3. The preparation method according to claim 1 or 2, characterized in that: The concentration of the hydrochloric acid solution in step (1) is 10-37 wt %; Preferably, the oxidant in step (1) comprises any one of potassium chlorate, sodium chlorate, hydrogen peroxide or chlorine, or a combination of at least two thereof; Preferably, the mass ratio of the oxidant to the platinum flakes in step (1) is 0.8 to 3:

1.

4. The preparation method according to any one of claims 1 to 3, characterized in that The terminal temperature of the heating in step (2) is 60-100° C.; Preferably, the platinum precipitant in step (2) comprises any one of ammonia water, potassium hydroxide, ammonium chloride or potassium chloride, or a combination of at least two thereof; Preferably, the mass ratio of the platinum precipitant to the platinum flakes is 0.5 to 4:

1.

5. The preparation method according to any one of claims 1 to 4, characterized in that: The washing liquid used in the first washing in step (2) comprises any one of sodium chloride solution, ammonium chloride solution or potassium chloride solution, or a combination of at least two thereof; Preferably, the number of washings in step (2) is 3 to 5 times; Preferably, the temperature of the drying treatment in step (2) is 80 to 180°C; Preferably, the drying time in step (2) is 1 to 16 hours.

6. The preparation method according to any one of claims 1 to 5, characterized in that: The reducing mixed solution in step (3) comprises deionized water and a reducing agent; Preferably, the temperature of the deionized water is 80-100°C; Preferably, the reducing agent comprises hydrazine hydrate; Preferably, the content of the reducing agent in the reducing mixed solution is 1 to 30 wt %.

7. The preparation method according to any one of claims 1 to 6, characterized in that: The stirring speed in step (3) is 70 to 180 r / min.

8. The preparation method according to any one of claims 1 to 7, characterized in that: The washing liquid used in the secondary washing in step (3) comprises deionized water; Preferably, the number of secondary washings in step (3) is 3 to 5 times.

9. The preparation method according to any one of claims 1 to 8, characterized in that: The power of the ultrasonic cleaning in step (3) is 100 to 800 W; Preferably, the drying temperature in step (3) is 80 to 180°C; Preferably, the drying time in step (3) is 1 to 36 hours.

10. The preparation method according to any one of claims 1 to 9, characterized in that: The preparation method comprises the following steps: (1) immersing a platinum sheet having a thickness of 0.05 to 0.3 mm in a hydrochloric acid solution having a concentration of 10 to 38 wt %, and then mixing an oxidant, heating and boiling until the platinum sheet is completely dissolved, and then cooling and filtering once to obtain a platinum-containing filtrate; Wherein, the mass ratio of the oxidant to the platinum flakes is 0.8 to 3:1; (2) heating the platinum-containing filtrate obtained in step (1) to 60-100° C., mixing with a platinum precipitant, and then filtering twice, washing once 3-5 times, and drying at 80-180° C. for 1-16 hours to obtain a platinum salt powder; Wherein, the mass ratio of the platinum precipitant to the platinum flakes is 0.5 to 4:1; (3) adding the platinum salt powder obtained in step (2) to the reducing mixed solution under stirring conditions at a speed of 70 to 180 r / min, and then sequentially allowing to stand, filtering three times, washing twice with deionized water for 3 to 5 times, ultrasonically cleaning, and drying to obtain the porous platinum powder; The reducing mixed solution comprises deionized water at a temperature of 80 to 100° C. and a reducing agent; the content of the reducing agent is 1 to 30 wt %; The power of the ultrasonic cleaning is 100-800W; the temperature of the drying is 80-180°C, and the time is 1-36h.

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