Platinum-based hollow nanorods with ultrathin wall thickness, and preparation method and application thereof

Abstract

The application belongs to the field of nanometer materials, and specifically discloses an ultrathin platinum-based hollow nanorod with a wall thickness less than 4 nm, a preparation method and application thereof. The preparation method comprises the following steps: adding tellurium and selenium precursors into a solution containing a reducing agent and continuously stirring by magnetic force, then performing solid-liquid separation to obtain tellurium-selenium nanorods; obtaining a structure of a platinum alloy coated tellurium-selenium template, then adding hydrogen peroxide solution into an aqueous solution containing an intermediate product and reacting for a preset time, performing solid-liquid separation to obtain a precipitate after the reaction is completed, and finally obtaining the ultrathin platinum alloy hollow nanorod. If no other noble metal precursor is added when the platinum precursor is added, the ultrathin platinum hollow nanorod can be obtained. The application mainly controls the reaction rate of the noble metal precursor and the tellurium-selenium template by using ethylene glycol and polyvinylpyrrolidone, and removes the unreacted tellurium-selenium template by using hydrogen peroxide etching, so that the prepared ultrathin platinum-based hollow nanorod has a wall thickness less than 4 nm.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of nanomaterials, and more particularly relates to a platinum-based hollow nanorod with an ultrathin wall thickness and a preparation method and application thereof. BACKGROUND

[0002] Platinum materials have very high catalytic activity in many chemical reactions due to their unique physical and chemical properties, such as catalytic reactions of nitrogen oxides in automobile exhaust treatment, oxygen reduction reactions at the cathode of fuel cells and hydrogen oxidation reactions at the anode, and many industrial catalytic reactions. In addition, with the in-depth study of nanometer enzymes by researchers in recent years, the excellent enzyme-like activity of platinum nanomaterials has also been gradually discovered and verified, especially the hollow structure of platinum nanomaterials, which has excellent specific activity, which plays an important role in the further popularization and application of platinum nanometer enzymes in analysis and detection and biomedicine. However, platinum is a precious metal material with limited reserves and high price. In order to improve the utilization rate of the material and reduce the application cost, it is necessary to improve the catalytic activity of platinum materials as much as possible.

[0003] Increasing the specific surface area and the proportion of surface atoms by reducing the size of platinum nanoparticles is an effective way to improve catalytic activity, but too small size will cause the surface energy to be too high, causing agglomeration, resulting in a decrease in the activity and stability of 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, and more importantly, they can provide abundant defect sites, which play a very important role in improving catalytic activity. Hollow nanotubes or nanorods combine the advantages of nanowires and nanosheets, which can provide high specific surface area and abundant defect sites, thereby providing high catalytic activity. In addition, doping other metals in platinum nanomaterials or preparing platinum-based alloys is also an effective way to improve catalytic activity. For example, Han's group reported a platinum nanotube with high enzyme-like activity (Chem. Commun. 2013, 49, 6024-6026), which was synthesized in an aqueous solution using tellurium nanorods as a template; Cai's group reported platinum-based alloy hollow nanorods obtained by reacting in an aqueous solution using tellurium nanorods as a template, which have higher activity than pure platinum hollow nanorods (Dalton. 2024, 53, 5624-5631; Dalton. 2024, 53, 17324-17332), and the activity (specific activity) of the alloy material per unit mass can be as high as 863 U / mg, which is much higher than that of pure platinum (330 U / mg). However, due to the fast reaction rate in the aqueous solvent, the wall thickness of the obtained material is large, and the specific activity cannot be further improved by reducing the wall thickness of the nanorod. SUMMARY

[0004] In view of the above-mentioned shortcomings of the prior art, the present application aims to provide a platinum-based hollow nanorod with an ultrathin wall thickness and a preparation method thereof.

[0005] The technical solution of the present application is as follows:

[0006] The preparation method of the platinum-based hollow nanorod with an ultrathin wall thickness comprises the following steps:

[0007] The tellurium precursor and the selenium precursor are added into a solution containing a reducing agent and subjected to magnetic stirring. After a preset reaction time, the solution is transferred into an aqueous solution containing sodium dodecyl sulfate and subjected to sufficient stirring. Then, solid-liquid separation is performed to obtain a precipitate, thereby obtaining a tellurium-selenium nanorod.

[0008] (b) The tellurium-selenium nanorod obtained in step (a) is dispersed in a polyvinylpyrrolidone-containing ethylene glycol solution. Then, a platinum precursor and a precursor of another noble metal (ruthenium, rhodium, iridium or osmium) are added into the solution, and subjected to a preset reaction time. Centrifugal separation is performed to obtain a structure of the noble metal-coated tellurium-selenium template. Then, hydrogen peroxide is added into the solution containing the structure and subjected to a preset reaction time. After the reaction is completed, solid-liquid separation is performed to obtain a precipitate. Finally, an ultrathin platinum alloy hollow nanorod is obtained. If no other noble metal precursor is added when the platinum precursor is added, an ultrathin platinum hollow nanorod of a single metal can be obtained.

[0009] As a further preferred embodiment, in step (a), the tellurium precursor is one or more of tellurium dioxide, tellurous acid and tellurite; the selenium precursor is one or more of selenious acid and selenite; and the reducing agent is hydrazine hydrate.

[0010] As a further preferred embodiment, in step (a), the reaction temperature is 35 ℃ to 45 ℃, the reaction time after the addition of the tellurium precursor and the selenium precursor is 15 min to 25 min, and the amount-of-substance ratio of the tellurium precursor to the selenium precursor is 200:1 to 10:1.

[0011] As a further preferred embodiment, in step (b), the platinum precursor is a chloroplatinic acid or chloroplatinic acid salt solution, the ruthenium, rhodium, iridium or osmium precursor is a corresponding chloride, and the concentration of the polyvinylpyrrolidone is less than 50 μg / mL.

[0012] As a further preferred embodiment, in step (b), the reaction temperature of the noble metal precursor in the ethylene glycol solution is 25 ℃ to 65 ℃, the reaction time is 1 h to 12 h, and the reaction time of the hydrogen peroxide is 0.1 h to 3 h.

[0013] According to another aspect of the present application, a platinum-based hollow nanorod with an ultrathin wall thickness prepared by the above-mentioned method is provided.

[0014] As a further preferred embodiment, the platinum-based hollow nanorod with ultrathin wall thickness includes a shell and a hollow region formed by the shell covering the hollow region. The wall thickness of the platinum-based hollow nanorod with ultrathin wall thickness does not exceed 4 nm, its length is 70 nm to 200 nm, and its diameter is 25 nm to 50 nm.

[0015] According to another aspect of the present invention, the above-mentioned platinum-based hollow nanorods with ultrathin walls are provided as catalysts or enzymes in multiple fields.

[0016] The advantages of this invention compared to the prior art are as follows:

[0017] This invention first obtains tellurium selenide nanorods via a co-reduction method, then uses them as a chemical template to undergo an electro-displacement substitution reaction with platinum precursors and other noble metal precursors in an ethylene glycol solution to obtain a structure in which a thin layer of noble metals coats the tellurium selenide template. Then, hydrogen peroxide is added to etch the unreacted template in the middle, and finally, centrifugation and washing are performed to obtain ultrathin platinum-based hollow nanorods with a wall thickness of no more than 4 nm.

[0018] Ethylene glycol and hydrogen peroxide both play crucial roles here, and neither can be omitted. Ethylene glycol cannot be replaced by glycerol because the latter is too viscous, making it difficult for the template to react and separate. Ethylene glycol also cannot be replaced or partially replaced by water because the presence of water will form large metal particles. When reacting in pure water, as... Figure 1 As shown, the products consist of relatively large particles with significantly increased wall thickness, especially at a 1:1 ratio of ethylene glycol to water. Figure 2 As shown, many particles adhere 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 after 48 hours, the product still contains a large amount of template structure instead of a hollow structure (see...). Figure 3 When treated with hydrogen peroxide, the intermediate tellurene template can be rapidly and completely oxidized to tellurite or selenite ions, which are then removed by centrifugation. This process does not produce any contaminants in the product, and excess hydrogen peroxide decomposes into water and oxygen without any further impurities. Furthermore, the ultrathin platinum-based hollow nanorods prepared in this invention possess the properties and advantages of high specific surface area and high dispersibility. In particular, their wall thickness of no more than 4 nm gives them excellent mass activity in catalytic reactions, meaning that a unit mass of catalytic material exhibits a high level of activity. This is significant for improving platinum utilization and reducing costs. Attached Figure Description

[0019] Figure 1 The image shows a TEM image of the reaction products when the solvent is pure water.

[0020] Figure 2 TEM image of the reaction product when the solvent is a 1:1 mixture of ethylene glycol and water;

[0021] Figure 3 TEM image of the reaction product without the addition of hydrogen peroxide;

[0022] Figure 4 Process flow diagram of the present application;

[0023] Figure 5 TEM image of the ultrathin platinum hollow nanorod. DETAILED DESCRIPTION

[0024] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and do not limit the present application. In addition, the technical features involved in the various embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0025] As shown in Figure 4 The present application provides a preparation method of an ultrathin platinum-based hollow nanorod, which comprises the following steps:

[0026] (a) adding tellurium precursor and selenium precursor into a solution containing a reducing agent and continuously stirring under magnetic force, and after a preset reaction time, transferring into an aqueous solution containing sodium dodecyl sulfate and fully stirring, and then performing solid-liquid separation to obtain a precipitate, thereby preparing a tellurium selenium nanorod;

[0027] (b) dispersing the tellurium selenium nanorod prepared in step (a) in a polyvinylpyrrolidone-containing ethylene glycol solution, and then adding a platinum precursor and other noble metal (ruthenium, rhodium, iridium or osmium) precursor into the solution and reacting for a preset time, centrifugally separating to obtain a noble metal-coated tellurium selenium template structure, and then adding hydrogen peroxide into the solution containing the above structure and reacting for a preset time, and after the reaction is completed, performing solid-liquid separation to obtain a precipitate, and finally preparing an ultrathin platinum alloy hollow nanorod. If no other noble metal precursor is added when the platinum precursor is added, an ultrathin platinum hollow nanorod of a single metal can be obtained.

[0028] As a further preferred, in step (a), the tellurium precursor is one or more of tellurium dioxide, tellurous acid and tellurite; the selenium precursor is one or more of selenious acid and selenite; and the reducing agent is hydrazine hydrate.

[0029] As further preferred, in step (a), the reaction temperature is 35 ℃ ~ 45 ℃, the reaction time after adding the tellurium precursor and selenium precursor is 15 min ~ 25 min, and the molar ratio of the substance of the tellurium precursor to the selenium precursor is 200 : 1 ~ 10 : 1.

[0030] As further preferred, in step (b), the platinum precursor substance is chloroplatinic acid or chloroplatinic acid salt solution, the ruthenium, rhodium, iridium or osmium precursor substance is the corresponding chloride, and the concentration of the polyvinylpyrrolidone is less than 50 μg / mL.

[0031] As further preferred, in step (b), the reaction temperature of the noble metal precursor substance in the ethylene glycol solution is 25 ℃ ~ 65 ℃, the reaction time is 1 h ~ 12 h, and the reaction time of adding hydrogen peroxide is 0.1 h ~ 3 h.

[0032] According to another aspect of the present application, there is provided an ultrathin platinum-based hollow nanorod prepared by the above method, which comprises a shell and a hollow region formed by the shell, the wall thickness of the nanorod is not more than 4 nm, the length is 70 nm ~ 200 nm, and the diameter is 25 nm ~ 50 nm. Figure 5 is a TEM image of the ultrathin platinum hollow nanorod prepared in a preferred embodiment of the present application, from which it can be seen that the average length of the nanorod is about 95 nm, the average diameter is about 45 nm, and the thickness is not more than 4 nm.

[0033] The present application will be further described below according to specific embodiments. Example 1

[0034] (a) adding tellurium dioxide and selenious acid into a hydrazine hydrate solution, fully stirring and reacting at a temperature of 40 ℃, wherein the molar ratio of tellurium dioxide to selenious acid is 100:1, diluting the hydrazine hydrate solution in a solution containing sodium dodecyl sulfate after 16 min of reaction, fully stirring for 10 min, and then centrifuging to obtain a precipitate, thereby preparing tellurium selenium nanorods;

[0035] (b) dispersing the tellurium selenium nanorods prepared in step (a) in a polyvinylpyrrolidone-containing ethylene glycol solution at 30 ℃, wherein the molar concentration of polyvinylpyrrolidone is about 40 μg / mL, then adding a chloroplatinic acid solution and an iridium chloride solution, wherein the molar ratio of chloroplatinic acid to iridium chloride is 10:1, stirring and reacting for 3 h, centrifuging, dispersing the product in pure water, adding a 30% hydrogen peroxide aqueous solution and reacting for 0.5 h, and then performing solid-liquid separation to obtain a precipitate, thereby preparing ultrathin platinum iridium hollow nanorods. Example 2

[0036] (a) sodium tellurite and selenium dioxide were added into hydrazine hydrate solution, and the reaction was carried out under the condition of 35 °C with sufficient stirring, wherein the molar ratio of sodium tellurite to selenium dioxide was 200:1, after 20 min, the hydrazine hydrate solution was diluted in a solution containing sodium dodecyl sulfate, and after 10 min of sufficient stirring, solid-liquid separation was carried out to obtain the precipitate, thereby obtaining tellurium selenium nanorods;

[0037] (b) the tellurium selenium nanorods prepared in step (a) were dispersed in a polyvinylpyrrolidone-containing ethylene glycol solution at 50 °C, wherein the molar concentration of polyvinylpyrrolidone was about 20 μg / mL, then a chloroplatinic acid solution and a rhodium chloride solution were added, wherein the molar ratio of chloroplatinic acid to rhodium chloride was 10:2, the reaction was stirred for 2 h, centrifugal separation was carried out, the product was dispersed in pure water, 30% hydrogen peroxide aqueous solution was added and reacted for 0.25 h, and after the reaction was completed, solid-liquid separation was carried out to obtain the precipitate, thereby obtaining ultra-thin platinum rhodium hollow nanorods. Example 3

[0038] (a) sodium tellurite and selenium dioxide were added into hydrazine hydrate solution, and the reaction was carried out under the condition of 35 °C with sufficient stirring, wherein the molar ratio of sodium tellurite to selenium dioxide was 200:1, after 20 min, the hydrazine hydrate solution was diluted in a solution containing sodium dodecyl sulfate, and after 10 min of sufficient stirring, solid-liquid separation was carried out to obtain the precipitate, thereby obtaining tellurium selenium nanorods;

[0039] (b) the tellurium selenium nanorods prepared in step (a) were dispersed in a polyvinylpyrrolidone-containing ethylene glycol solution at 50 °C, wherein the molar concentration of polyvinylpyrrolidone was about 20 μg / mL, then a chloroplatinic acid solution and a rhodium chloride solution were added, wherein the molar ratio of chloroplatinic acid to rhodium chloride was 10:2, the reaction was stirred for 2 h, centrifugal separation was carried out, the product was dispersed in pure water, 30% hydrogen peroxide aqueous solution was added and reacted for 0.25 h, and after the reaction was completed, solid-liquid separation was carried out to obtain the precipitate, thereby obtaining ultra-thin platinum rhodium hollow nanorods.

Claims

1. A method for preparing platinum-based hollow nanorods with ultrathin walls, characterized in that, The preparation method includes the following steps: (a) The tellurium precursor and the selenium precursor are added to a solution containing hydrazine hydrate and continuously stirred magnetically. The tellurium precursor is one or more of tellurium dioxide, tellurite, and tellurite, and the selenium precursor is one or more of selenite and selenite. After the reaction has been carried out for a preset time, an aqueous solution containing sodium dodecyl sulfate is added and stirred thoroughly. Then, solid-liquid separation is performed to obtain the precipitate, thereby preparing tellurium selenide nanorods. (b) The tellurium selenide nanorods obtained in step (a) are dispersed in an ethylene glycol solution containing polyvinylpyrrolidone. Then, a platinum precursor and a precursor of ruthenium, rhodium, iridium, or osmium are added to the solution. 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 chloroiridium acid or iridium tetrachloride, and the osmium precursor is potassium osmium hydrate or osmium tetrachloride. The reaction is carried out for a preset time to obtain a tellurium selenide template structure coated with a platinum alloy containing platinum and other noble metals. Then, hydrogen peroxide is added to the solution containing the above structure and the reaction is carried out for a preset time. After the reaction is completed, solid-liquid separation is performed to obtain the precipitate. Finally, ultrathin platinum alloy hollow nanorods are obtained. If no other noble metal precursors are added when adding the platinum precursor, single-metal ultrathin platinum hollow nanorods can be obtained.

2. The method for preparing platinum-based hollow nanorods with ultrathin walls as described in claim 1, characterized in that, In step (b), the reaction time of the noble metal precursor in the ethylene glycol solution is 1 h to 12 h, and the reaction time after adding hydrogen peroxide is 0.1 h to 3 h.

3. A platinum-based hollow nanorod with ultrathin wall thickness prepared by the method described in any one of claims 1 to 2, comprising a single-metal platinum hollow nanorod or a multi-metal platinum alloy hollow nanorod.

4. The platinum-based hollow nanorod with ultrathin wall thickness as described in claim 3, characterized in that, The ultrathin platinum-based hollow nanorod includes a shell and a hollow region formed by the shell, the thickness of which does not exceed 4 nm.

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

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