Platinum-based hollow nanorod with ultra-thin wall thickness as well as preparation method and application of platinum-based hollow nanorod

Abstract

The invention belongs to the field of nanometer materials, and particularly discloses an ultrathin platinum-based hollow nanorod with the wall thickness smaller than 4 nm and a preparation method and application of the ultrathin platinum-based hollow nanorod. The preparation method comprises the following steps: adding a tellurium precursor and a selenium precursor into a solution containing a reducing agent, continuously magnetically stirring, and then carrying out solid-liquid separation to obtain the tellurium-selenium nanorod, then adding a hydrogen peroxide solution into an aqueous solution containing an intermediate product, carrying out a reaction for a preset time, carrying out solid-liquid separation after the reaction is finished so as to obtain a precipitate, and finally, preparing the ultrathin platinum alloy hollow nanorod. If other noble metal precursors are not added when the platinum precursor is added, the ultrathin platinum hollow nanorod can be obtained. The reaction rate of the noble metal precursor and the tellurium-selenium template is controlled mainly through ethylene glycol and polyvinylpyrrolidone, and the unreacted tellurium-selenium template is removed through hydrogen peroxide etching, so that the prepared ultrathin platinum-based hollow nanorod has the wall thickness smaller than 4 nm.

Description

Technical Field

[0001] The present invention belongs to the field of nanomaterials, and more specifically, relates to a platinum-based hollow nanorod with ultra-thin walls, a preparation method thereof, and an application thereof. Background Art

[0002] Due to their unique physical and chemical properties, platinum materials exhibit very high catalytic activity in many chemical reactions, such as the catalytic reaction of nitrogen oxides in automobile exhaust treatment, the oxygen reduction reaction at the cathode and hydrogen oxidation reaction at the anode of fuel cells, as well as their irreplaceable role and status in many industrial catalytic reactions. In addition, with the in-depth study of nanozymes by researchers in recent years, the excellent enzyme-like activity of platinum nanomaterials has also been gradually discovered and confirmed, especially hollow-structured platinum nanomaterials, which have shown excellent specific activity. This plays an important role in the further promotion and application of platinum nanozymes in analytical detection and biomedicine. However, platinum is a precious metal material with scarce reserves and high price. In order to improve the utilization rate of materials and reduce application costs, it is necessary to improve the catalytic activity of platinum materials as much as possible.

[0003] Increasing the specific surface area and increasing the surface atomic ratio by reducing the size of platinum nanoparticles is an effective way to improve catalytic activity. However, too small a size will cause the surface energy to be too high, resulting in agglomeration, which leads to a decrease in the activity and stability of the platinum nanoparticles. Designing nanomaterials into very thin nanowires or nanosheets is an effective solution, which can maintain a high specific surface area and improve stability. More importantly, they can provide abundant defect sites, which play a very important role in improving catalytic activity. Hollow-structured nanotubes or nanorods combine the advantages of nanowires and nanosheets, and can provide high specific surface area and abundant defect sites, thereby providing high catalytic activity. In addition, doping platinum nanomaterials with other metals or preparing platinum-based alloys is also an effective way to improve catalytic activity. For example, Han's group reported platinum nanotubes with high enzyme-like activity (Chem. Commun. 2013, 49, 6024-6026). These nanotubes were synthesized in aqueous solution using tellurium nanorods as templates. Cai's group also reported platinum-based hollow alloy nanorods, also synthesized in aqueous solution using tellurium nanorods as templates, exhibiting higher activity than pure platinum hollow nanorods (Dalton. 2024, 53, 5624-5631; Dalton. 2024, 53, 17324-17332). The specific activity per unit mass of the alloy material reached 863 U / mg, far exceeding the 330 U / mg of pure platinum. However, due to the rapid reaction rate in aqueous solvent, the resulting material had a relatively thick wall, making it difficult to further increase the specific activity by reducing the nanorod wall thickness. Summary of the Invention

[0004] In view of the above-mentioned shortcomings of the prior art, the object of the present invention is to provide a platinum-based hollow nanorod with ultra-thin wall thickness and a preparation method thereof.

[0005] The technical solution of the present invention is: A method for preparing platinum-based hollow nanorods with ultra-thin walls, comprising the following steps: Adding a tellurium precursor and a selenium precursor to a solution containing a reducing agent and continuously stirring the solution with a magnetic stirrer, adding an aqueous solution of sodium dodecyl sulfate after a predetermined reaction time and stirring the solution thoroughly, and then performing solid-liquid separation to obtain a precipitate, thereby preparing tellurium-selenium nanorods; (b) dispersing the tellurium selenide nanorods prepared in step (a) in an ethylene glycol solution containing polyvinyl pyrrolidone, then adding a platinum precursor and a precursor of another noble metal (ruthenium, rhodium, iridium, or osmium) to the solution, allowing the reaction to proceed for a predetermined time, and centrifuging to obtain a structure comprising a tellurium selenide template coated with a noble metal. Hydrogen peroxide is then added to the solution containing the structure and allowed to react for a predetermined time. After the reaction is complete, solid-liquid separation is performed to obtain a precipitate, thereby obtaining ultrathin platinum alloy hollow nanorods. If no other noble metal precursors are added when the platinum precursor is added, ultrathin platinum hollow nanorods composed of a single metal can be obtained.

[0006] As further preferred, in step (a), the tellurium precursor is one or more of tellurium dioxide, tellurous acid and tellurites; the selenium precursor is one or more of selenous acid and selenites; and the reducing agent is hydrazine hydrate.

[0007] As further preferred, in step (a), the reaction temperature is 35°C to 45°C, the reaction time after adding the tellurium precursor and the selenium precursor is 15 min to 25 min, and the molar ratio of the tellurium precursor to the selenium precursor is 200:1 to 10:1.

[0008] As further preferred, in step (b), the platinum precursor is chloroplatinic acid or a chloroplatinate solution, the ruthenium, rhodium, iridium or osmium precursor is the corresponding chloride, and the concentration of polyvinyl pyrrolidone is less than 50 μg / mL.

[0009] As further preferred, in step (b), the noble metal precursor is reacted in the ethylene glycol solution at a temperature of 25° C. to 65° C. for a reaction time of 1 h to 12 h, and the hydrogen peroxide is added for a reaction time of 0.1 h to 3 h.

[0010] According to another aspect of the present invention, there is provided a platinum-based hollow nanorod with ultra-thin wall thickness prepared by the above method.

[0011] As a further preference, the platinum-based hollow nanorod with ultra-thin walls comprises a shell and a hollow region formed by the shell, the wall thickness of the platinum-based hollow nanorod with ultra-thin walls does not exceed 4 nm, the length thereof is 70 nm to 200 nm, and the diameter thereof is 25 nm to 50 nm.

[0012] According to another aspect of the present invention, there is provided an application of the above-mentioned platinum-based hollow nanorods with ultra-thin walls as catalysts or enzyme-like substances in multiple fields.

[0013] The beneficial effects of the present invention compared with the prior art are: The present invention first obtains tellurium selenide nanorods through a co-reduction method, then uses them as chemical templates to undergo an galvanic replacement reaction with a platinum precursor and other precious metal precursors in an ethylene glycol solution to obtain a structure in which a thin layer of precious metal is coated with the tellurium selenide template. Hydrogen peroxide is then added to etch the unreacted template in the middle, and finally centrifugation and washing are performed to obtain ultra-thin platinum-based hollow nanorods with a wall thickness of no more than 4 nm.

[0014] Here, both ethylene glycol and hydrogen peroxide play a very important role and neither of them can be missing. Ethylene glycol cannot be replaced by glycerol because the latter is too viscous and the template is not easy to react and separate. Ethylene glycol cannot be replaced or partially replaced by water because large metal particles will be formed when water is present. When reacting in pure water, Figure 1 As shown in Figure 2, the products are composed of larger particles with significantly increased wall thickness. When the ratio of ethylene glycol to water is 1:1, Figure 2 As shown, many particles will be attached to the surface of the reaction product. Hydrogen peroxide is also important for the formation of ultrathin hollow nanorods. If the intermediate product obtained in ethylene glycol is not treated with hydrogen peroxide, even if it is left for 48 hours, the product still contains a large number of template structures rather than hollow structures (see Figure 3 When treated with hydrogen peroxide, the intermediate tellurium selenide template is quickly and completely oxidized into tellurite or selenite ions, which can then be removed by centrifugation without generating any contaminating impurities in the product. Furthermore, the excess hydrogen peroxide decomposes into water and oxygen, also free of impurities. Furthermore, the ultrathin platinum-based hollow nanorods prepared by the present invention possess the properties and advantages of high specific surface area and high dispersibility. In particular, their wall thickness, which does not exceed 4 nm, enables them to exhibit excellent mass activity in catalytic reactions—that is, the activity per unit mass of the catalytic material. This has positive implications for improving platinum utilization and reducing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 TEM image of the reaction product when the solvent is pure water; Figure 2 This is the TEM image of the reaction product when the solvent is a 1:1 mixture of ethylene glycol and water; Figure 3 is the TEM image of the reaction product when no hydrogen peroxide is added; Figure 4 is a process flow chart of the present invention; Figure 5 TEM image of ultrathin platinum hollow nanorods. DETAILED DESCRIPTION

[0016] In order to make the objectives, technical solutions, and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0017] like Figure 4 As shown, an embodiment of the present invention provides a method for preparing ultrathin platinum-based hollow nanorods, the preparation method comprising the following steps: (a) adding a tellurium precursor and a selenium precursor to a solution containing a reducing agent and continuously stirring the solution under magnetic stirring; after a predetermined reaction time, adding an aqueous solution of sodium dodecyl sulfate and stirring the solution thoroughly; and then performing solid-liquid separation to obtain a precipitate, thereby producing tellurium-selenium nanorods; (b) dispersing the tellurium selenide nanorods prepared in step (a) in an ethylene glycol solution containing polyvinyl pyrrolidone, then adding a platinum precursor and a precursor of another noble metal (ruthenium, rhodium, iridium, or osmium) to the solution, allowing the reaction to proceed for a predetermined time, and centrifuging to obtain a structure comprising a tellurium selenide template coated with a noble metal. Hydrogen peroxide is then added to the solution containing the structure and allowed to react for a predetermined time. After the reaction is complete, solid-liquid separation is performed to obtain a precipitate, thereby obtaining ultrathin platinum alloy hollow nanorods. If no other noble metal precursors are added when the platinum precursor is added, ultrathin platinum hollow nanorods composed of a single metal can be obtained.

[0018] As further preferred, in step (a), the tellurium precursor is one or more of tellurium dioxide, tellurous acid and tellurites; the selenium precursor is one or more of selenous acid and selenites; and the reducing agent is hydrazine hydrate.

[0019] As further preferred, in step (a), the reaction temperature is 35°C to 45°C, the reaction time after adding the tellurium precursor and the selenium precursor is 15 min to 25 min, and the molar ratio of the tellurium precursor to the selenium precursor is 200:1 to 10:1.

[0020] As further preferred, in step (b), the platinum precursor is chloroplatinic acid or a chloroplatinate solution, the ruthenium, rhodium, iridium or osmium precursor is the corresponding chloride, and the concentration of polyvinyl pyrrolidone is less than 50 μg / mL.

[0021] As further preferred, in step (b), the noble metal precursor is reacted in the ethylene glycol solution at a temperature of 25° C. to 65° C. for a reaction time of 1 h to 12 h, and the hydrogen peroxide is added for a reaction time of 0.1 h to 3 h.

[0022] According to another aspect of the present invention, an ultrathin platinum-based hollow nanorod prepared using the above method is provided. The ultrathin platinum-based hollow nanorod includes a shell and a hollow area formed by the shell. The wall thickness of the nanorod does not exceed 4 nm, its length is 70 nm to 200 nm, and its diameter is 25 nm to 50 nm. Figure 5 This is a TEM image of ultrathin platinum hollow nanorods prepared in a preferred embodiment of the present invention. From the figure, it can be seen that the average length of the nanorods is about 95 nm, the average diameter is about 45 nm, and the thickness does not exceed 4 nm.

[0023] The present invention will be further described below with reference to specific embodiments. Example 1

[0024] (a) Tellurium dioxide and selenious acid were added to a hydrazine hydrate solution and stirred at 40°C, wherein the molar ratio of tellurium dioxide to selenious acid was 100:1. After 16 minutes of reaction, the hydrazine hydrate solution was diluted in a solution containing sodium dodecyl sulfate, stirred for 10 minutes, and then centrifuged to obtain a precipitate, thereby preparing tellurium selenide nanorods; (b) The tellurium selenide nanorods prepared in step (a) are dispersed in an ethylene glycol solution containing polyvinyl pyrrolidone at 30°C, wherein the molar concentration of the polyvinyl pyrrolidone is about 40 μg / mL, and then a chloroplatinic acid solution and an iridium chloride solution are added, wherein the molar ratio of chloroplatinic acid to iridium chloride is 10:1. The mixture is stirred for 3 h and centrifuged. The product is dispersed in pure water, 30% aqueous hydrogen peroxide solution is added and reacted for 0.5 h, and then solid-liquid separation is performed to obtain a precipitate, thereby preparing ultrathin platinum-iridium hollow nanorods. Example 2

[0025] (a) Sodium tellurite and selenious acid were added to a hydrazine hydrate solution and stirred at 35°C for reaction. The molar ratio of sodium tellurite to selenious acid was 200:1. After 20 minutes of reaction, the hydrazine hydrate solution was diluted in a solution containing sodium dodecyl sulfate. After stirring for 10 minutes, solid-liquid separation was performed to obtain a precipitate, thereby obtaining tellurium selenide nanorods. (b) The tellurium selenide nanorods prepared in step (a) are dispersed in an ethylene glycol solution containing polyvinyl pyrrolidone at 50°C, wherein the molar concentration of polyvinyl pyrrolidone is about 20 μg / mL, and then a chloroplatinic acid solution and a rhodium chloride solution are added, wherein the molar ratio of chloroplatinic acid to rhodium chloride is 10:2. The mixture is stirred for 2 h and centrifuged. The product is dispersed in pure water, and a 30% aqueous hydrogen peroxide solution is added and reacted for 0.25 h. After the reaction is completed, solid-liquid separation is performed to obtain a precipitate, thereby preparing ultrathin platinum-rhodium hollow nanorods. Example 3

[0026] (a) Tellurium dioxide and selenious acid were added to a hydrazine hydrate solution and stirred at 42°C, wherein the molar ratio of tellurium dioxide to selenious acid was 30:1. After 15 minutes of reaction, the hydrazine hydrate solution was diluted in a solution containing sodium dodecyl sulfate, stirred for 10 minutes, and then solid-liquid separation was performed to obtain a precipitate, thereby obtaining tellurium selenide nanorods; (b) The tellurium selenide nanorods prepared in step (a) are dispersed in an ethylene glycol solution containing polyvinyl pyrrolidone at 25°C, wherein the molar concentration of the polyvinyl pyrrolidone is about 10 μg / mL. A chloroplatinic acid solution is then added, and the mixture is stirred for 8 h. The mixture is centrifuged and the product is dispersed in pure water. A 30% aqueous hydrogen peroxide solution is added and the mixture is reacted for 2 h. After the reaction is completed, solid-liquid separation is performed to obtain a precipitate, thereby producing ultrathin platinum hollow nanorods.

Claims

1. A method for preparing platinum-based hollow nanorods with ultra-thin wall thickness, characterized in that: The preparation method comprises the following steps: (a) adding a tellurium precursor and a selenium precursor to a solution containing hydrazine hydrate and continuously stirring them with magnetic force, wherein the tellurium precursor is one or more of tellurium dioxide, tellurous acid, and tellurites, and the selenium precursor is one or more of selenous acid and selenites; after a predetermined reaction time, transferring the solution to an aqueous solution containing sodium dodecyl sulfate and stirring the solution thoroughly; and then performing solid-liquid separation to obtain a precipitate, thereby producing tellurium selenide nanorods; (b) dispersing the tellurium selenide nanorods obtained in step (a) in an ethylene glycol solution containing polyvinyl pyrrolidone, and then adding a platinum precursor and a precursor of other precious metals (ruthenium, rhodium, iridium or osmium) to the solution, wherein the platinum precursor is chloroplatinic acid or chloroplatinate (the ruthenium precursor is ruthenium trichloride or ruthenium tetrachloride, the rhodium precursor is sodium hexachlororhodiumate or rhodium trichloride hydrate, the iridium precursor is chloroiridic acid or iridium tetrachloride, and the osmium precursor is potassium osmate hydrate or osmium tetrachloride), and reacting for a preset time to obtain a tellurium selenide template structure coated with a platinum alloy containing platinum and other precious metals, and then adding hydrogen peroxide to the solution containing the above structure and reacting for a preset time. After the reaction is completed, solid-liquid separation is performed to obtain a precipitate, and finally ultra-thin platinum alloy hollow nanorods are obtained. If no other precious metal precursors are added when adding the platinum precursor, ultra-thin platinum hollow nanorods of a single metal can be obtained.

2. The method for preparing platinum-based hollow nanorods with ultra-thin walls according to claim 1, wherein: In step (b), the noble metal precursor reacts in the ethylene glycol solution for 1 h to 12 h, and the hydrogen peroxide is added for 0.1 h to 3 h.

3. A platinum-based hollow nanorod with ultra-thin wall thickness prepared by the method according to claims 1-2, including a single metal platinum hollow nanorod, a bimetallic or multimetallic platinum alloy hollow nanorod.

4. The platinum-based hollow nanorod with ultra-thin wall thickness according to claim 3, characterized in that: The ultrathin platinum-based hollow nanorod comprises a shell and a hollow region formed by covering the shell, and the thickness of the shell does not exceed 4 nm.

5. Use of the platinum-based hollow nanorods with ultrathin walls as claimed in claim 3 or 4 in the fields of enzyme-like catalysis, electrocatalysis, organic synthesis catalysis, analytical detection, and chemical kinetics for the treatment of diseases.

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