A platinum nanoparticle doped with non-precious metal, preparation method and application thereof

Abstract

The present invention discloses a platinum nanoparticle doped with a non-precious metal, a preparation method and an application thereof, aiming to realize the large-scale production and application of platinum-based nanoparticles with high efficiency, low cost and catalytic activity. In the early preparation process, ensure that the nanoscale inert bubbles are always full of the reaction liquid. The present invention uses sodium bicarbonate as a gas generator or other ceramics and thin film structures with micro-nano pores as micro-nano bubble generators to nanobubble the inert gas. The cyclically generated nanoscale bubbles can not only make the reactants contact evenly, but also provide a template effect in the nanoparticle formation stage, significantly increasing the active surface area of ​​the catalyst. The present invention can accurately adjust the size of platinum nanoparticles doped with non-precious metals by strictly controlling the size of nanobubbles and reaction conditions. This process provides an important means for optimizing catalyst performance and strongly supports the large-scale preparation of low-cost and high-efficiency catalysts.

Description

Technical Field

[0001] The invention relates to the field of nanotechnology and material science and technology, and more specifically to a platinum nanoparticle doped with a non-noble metal, a preparation method and an application thereof. Background Art

[0002] Platinum nanoparticles have a wide range of applications in the field of catalysis due to their unique physical and chemical properties. They have a high specific surface area and excellent catalytic activity, especially in fuel cells, chemical reaction accelerators and emission control systems. The preparation methods usually include chemical reduction, electrochemical deposition, sol-gel method and microemulsion technology. These methods aim to control the size, shape and dispersibility of nanoparticles, because these parameters directly affect the activity and stability of the catalyst. In the preparation process, the selection of appropriate reducing agents, protective agents and solvents is the key. Platinum nanoparticles are used as electrode materials in fuel cells to improve battery efficiency and power output; in the chemical industry, they are used to accelerate reactions, improve yields and selectivity; in environmental protection technologies, especially in automobile exhaust purification systems, they help remove harmful gases such as CO, NOx and VOCs. With the strengthening of environmental regulations and the increase in demand for clean energy, the demand for efficient and low-cost platinum nanoparticles is growing.

[0003] Platinum and other precious metals are widely used as catalysts, which are expensive and limited in resources despite their high catalytic efficiency. The high price and scarcity of precious metals limit the large-scale commercialization of these technologies because they increase the cost of the final product and cause concerns about the stability of the supply chain. There is an urgent need to develop catalysts that use less precious metals or non-precious metals as dopants to reduce costs and reduce dependence on scarce resources.

[0004] Therefore, in order to solve the above technical problems, it is necessary to provide platinum nanoparticles doped with non-precious metals, a preparation method and application thereof. Summary of the invention

[0005] The object of the present invention is to provide a platinum nanoparticle doped with a non-precious metal, a preparation method and an application thereof, so as to solve the above-mentioned problems.

[0006] In order to achieve the above object, the technical solution provided by the present invention is as follows:

[0007] A platinum nanoparticle doped with a non-noble metal, comprising the following components in terms of mass percentage:

[0008] Platinum salt: 0.1%-15% platinum salt solution;

[0009] Non-precious metal salt: 0.1%-15% non-precious metal salt solution;

[0010] Stabilizer: 0.1%-15% polyvinylpyrrolidone;

[0011] Reducing agent: 0.1%-80% reducing agent;

[0012] Circulating gas: 0.1%-15% sodium bicarbonate or inert gas;

[0013] Dispersant: 1%-95% dispersant.

[0014] As a further improvement of the present invention, the platinum salt is one or two of chloroplatinic acid, potassium chloroplatinate, sodium chloroplatinate, ammonium chloroplatinate, potassium chloroplatinite, sodium chloroplatinite, ammonium chloroplatinite, and diammine dichloroplatinum;

[0015] As a further improvement of the present invention, the non-precious metal salt is at least one of nickel, cobalt, iron, copper and zinc salts. Preferably, the non-precious metal salt is any one of nickel nitrate, nickel sulfate, nickel chloride and nickel acetate.

[0016] As a further improvement of the present invention, the reducing agent is at least one of sodium borohydride, lithium borohydride, ascorbic acid, diethylamine, ethanol or hydrogen.

[0017] As a further improvement of the present invention, the dispersant is one or two of distilled water, ethanol, ethylene glycol, polyethylene glycol, propylene glycol, and n-butanol.

[0018] A method for preparing platinum nanoparticles doped with non-noble metals comprises the following steps:

[0019] S1: preparing a platinum-containing precursor solution and a non-precious metal salt solution respectively, then gradually adding the non-precious metal salt solution to the platinum precursor solution, placing the mixture in an ultrasonic stirrer for mixing for 1 hour, and preparing a mixed solution containing platinum and non-precious metal salts;

[0020] S2: gradually add reducing agent A and stabilizer to the above mixed solution, place in an ultrasonic stirrer and continue mixing for 1 hour to ensure that the reactants are fully dissolved;

[0021] S3: pour the mixed solution in step 2 into a three-necked flask, place the flask in an oil bath, heat and stir, and control the temperature in the oil bath to keep constant for a period of time;

[0022] S4: During the oil bath heating process, inert gas is circulated and bubbled in the form of nanobubbles through a micro-nano bubble generator or sodium bicarbonate powder treated by microencapsulation technology is added to gradually release nano carbon dioxide bubbles, so that the reaction solution is always in a nanobubble supersaturated state;

[0023] S5: After the oil bath reaction is completed, the reducing agent B is added again, the reaction solution is poured into the reactor, and the reaction is continued for a period of time at a certain temperature;

[0024] S6: The reactor is naturally cooled to room temperature to obtain a platinum nano-colloidal solution doped with non-precious metals; the nanoparticles are further separated by centrifugation or filtration, and the platinum nanoparticles doped with non-precious metals are obtained after washing and drying.

[0025] As a further improvement of the present invention, the concentration of the dissolved platinum salt in S2 is 0.01 to 5 mol / L, and the concentration of the dissolved non-precious metal salt is 0.01 to 5 mol / L.

[0026] As a further improvement of the present invention, the concentration ratio of the platinum salt to the non-precious metal salt in S2 is between 1:1 and 1:15.

[0027] As a further improvement of the present invention, the temperature of the oil bath in S3 is between 60 and 120° C., and the heating time is between 0.3 and 5 hours.

[0028] As a further improvement of the present invention, the sodium bicarbonate powder in S4 needs to be processed by microencapsulation technology, which can gradually release nano-sized carbon dioxide bubbles, which helps platinum and non-precious metal salts to fully contact each other in the chemical reaction. By controlling the dissolved concentration of non-precious metals and platinum, it is beneficial to form uniform composite nanoparticles. Furthermore, the nanobubbles formed by the inert gas can prevent the local non-precious metal or platinum ion concentration from being too high, thereby avoiding uneven distribution to form larger particles, which is beneficial to obtain platinum nanoparticles of uniform size.

[0029] As a further improvement of the present invention, the micro-nano bubble generator in S4 can be ceramic, thin film or other structure that can generate nano bubbles.

[0030] As a further improvement of the present invention, if the reducing agent A is hydrogen, the oil bath heating process of S3 can be omitted, and the hydrogen can be directly circulated and bubbled into the mixed liquid through the micro-nano bubble generator for 10 minutes.

[0031] As a further improvement of the present invention, the hydrothermal temperature of the reactor in S5 is between 60 and 120° C., and the heating time is between 6 and 24 hours.

[0032] A platinum nano-colloidal solution doped with a non-precious metal can be used to prepare a hydrogen water concentration detection reagent.

[0033] Platinum nanoparticles doped with non-precious metals can be used in water electrolysis, fuel cells and other fields.

[0034] The above technical solutions can be freely combined under the premise of no contradiction.

[0035] Compared with the prior art, the advantages of the present invention are:

[0036] (1) Efficiently reduce the preparation cost of platinum nanoparticles. Traditional platinum nanoparticles are expensive and difficult to apply on a large scale. This solution successfully prepares doped non-precious metal platinum nanoparticles with excellent catalytic activity by precisely adding inexpensive non-precious metal salts, greatly reducing the cost of precious metal catalysts.

[0037] (2) Innovatively introduce the "inert gas nano-sizing" cyclic bubbling process to replace the traditional stirring method to further improve the catalytic activity of non-precious metal doped platinum nanoparticles. Traditional stirring is difficult to fully mix large-volume reaction liquids, and is particularly prone to causing platinum nanoparticles to adhere to the inner wall of the flask, which has a great impact on the observation of the reaction process for preparing platinum nanoparticles and the yield of the reactants. The introduction of inert nanobubbles can perfectly solve this experimental defect. The formation of nanobubbles by a micro-nano bubble generator not only helps to stir the reaction liquid and ensure uniform contact of the reactants, but also acts as a template in the process of nanoparticle formation to produce pore structures. These pore structures provide more active surfaces for the catalyst, which can significantly improve its reaction efficiency, thereby further optimizing the performance of the catalyst. In this scheme, the selection and control of the nanobubble size is crucial to achieving uniform mixing of platinum and non-precious metals, and helps to finely control the size of nanoparticles to form a doped structure with higher catalytic activity and stability.

[0038] (3) The innovative addition of "nano hydrogen bubbles" to the preparation process is expected to achieve large-scale industrial preparation of non-precious metal doped platinum nanoparticles. The present invention further clarifies the excellent role of hydrogen nano-sizing. Hydrogen is circulated and bubbled in the form of nanobubbles, which can eliminate the need for oil bath heating, save energy consumption and reaction time, further reduce the cost of catalyst preparation, and achieve large-scale preparation of non-precious metal doped platinum nanoparticles. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 A schematic diagram of a method for preparing platinum nanoparticles doped with non-precious metals according to the present invention;

[0040] Figure 2 The preparation conditions and nanoparticle size data table of platinum nanoparticles doped with non-precious metals according to Examples 1 to 4 of the present invention;

[0041] Figure 3 This is a performance test data table of non-precious metal-doped platinum nanoparticles used to prepare a hydrogen concentration detection reagent according to Example 9 of the present invention. DETAILED DESCRIPTION

[0042] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention; it is obvious that the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments, and all other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making creative work are within the scope of protection of the present invention.

[0043] Embodiment 1:

[0044] See also Figure 1 , a method for preparing platinum nanoparticles doped with non-precious metals, comprising the following steps:

[0045] S1: prepare 0.5 mol / L chloroplatinic acid solution and 0.2 mol / L nickel nitrate solution respectively, then gradually add the nickel nitrate solution to the platinum salt solution at a rate of 10 mL per minute, maintain the volume ratio of the platinum salt solution to the nickel nitrate solution at 10:1, place in an ultrasonic stirrer and mix for 1 hour to prepare a platinum-nickel mixed solution;

[0046] S2: gradually add ethanol 10 times the mass of the platinum salt and polyvinyl pyrrolidone 5 times the mass of the platinum salt to the above mixed solution, place in an ultrasonic stirrer and continue mixing for 1 hour to ensure that the reactants are fully dissolved;

[0047] S3: Pour the mixed solution in step 2 into a three-necked flask, place the flask in an oil bath, heat and stir, and control the temperature in the oil bath to be constant at 100° C. and heat for 40 minutes;

[0048] S4: During the oil bath heating process, sodium bicarbonate powder treated by microencapsulation technology is added to gradually release nano carbon dioxide bubbles so that the reaction solution is always in a nano bubble supersaturated state;

[0049] S5: After the oil bath reaction is completed, the reducing agent ascorbic acid is added again, the reaction solution is poured into the reactor, and the reactor is controlled to be kept at a constant temperature of 100° C. for 10 hours;

[0050] S6: The reactor is naturally cooled to room temperature to obtain a platinum nano-colloidal solution doped with non-precious metals; the nanoparticles are further separated by centrifugation or filtration, and the platinum nanoparticles doped with non-precious metals are obtained after washing and drying.

[0051] The addition of stabilizer PVP can prevent the aggregation of the formed nanoparticles, and the optimization of the amount of PVP can ensure the stability of the nanoparticles. Ethanol, as a reducing agent, can not only reduce the platinum salt, but also participate in the reaction as a solvent, which helps to control the growth rate and morphology of the nanoparticles. The nano-sized carbon dioxide bubbles produced by the decomposition of sodium bicarbonate can not only make the reactants evenly mixed, but also serve as a template to form pores in the formed metal nanoparticles to provide more active sites, enhance the contact between the material and the reactants, and thus improve the catalytic efficiency.

[0052] In the preparation method, nano-scale bubbles of different sizes can be generated by controlling the concentration of the gas generator and the reaction conditions, because sodium bicarbonate will react immediately after contacting the reaction solution, and the sodium bicarbonate powder treated by microencapsulation technology has a capsule shell outside that can ensure that the sodium bicarbonate powder reacts inside the solution; inert gas can also be passed through a micro-nano bubble generator with pores of different micro-nano sizes to generate nano-bubbles of different sizes.

[0053] Finally, unreacted precursors, stabilizer residues and other impurities can be effectively removed by centrifugation or filtration to further purify the nanoparticles. The drying step is to obtain solid materials that are easy to store and transport.

[0054] Since nanoparticles may aggregate during the drying process, spray drying, freeze drying and other techniques are used to control the dispersion state of the particles during the drying process. After drying is completed, ultrasonic dispersion or surface modification can be used to break up the aggregated particles. This is a prior art and will not be described in detail here.

[0055] Embodiment 2:

[0056] 0.5 mol / L of chloroplatinic acid was dissolved in a reaction container to prepare a platinum precursor solution, and 0.1 mol / L of nickel sulfate was dissolved in another container to prepare a non-noble metal salt solution.

[0057] Step 4 is changed to circulating nitrogen in the form of nanobubbles through a micro-nano bubble generator during the oil bath heating process, so that the reaction solution is always in an inert nanobubble supersaturated state.

[0058] The rest of the process is the same as in Example 2.

[0059] Embodiment 3:

[0060] 0.5 mol / L of chloroplatinic acid was dissolved in one reaction container to prepare a platinum precursor solution, and 0.2 mol / L of nickel chloride was dissolved in another container to prepare a non-noble metal salt solution.

[0061] The rest of the process is the same as in Example 2.

[0062] Embodiment 4:

[0063] 0.5 mol / L of chloroplatinic acid was dissolved in one reaction container to prepare a platinum precursor solution, and 0.5 mol / L of nickel acetate was dissolved in another container to prepare a non-noble metal salt solution.

[0064] In step 3, the mixture is heated to 80°C and maintained for 120 min.

[0065] The rest of the process is the same as in Example 2.

[0066] Embodiment 5:

[0067] The experimental steps refer to Example 2 to evaluate the effects of different nickel salt sources on the catalytic performance of doped non-precious metal platinum nanoparticles. The concentration of platinum salts remained unchanged, but the nickel source was changed from nickel sulfate to nickel nitrate, and other conditions remained unchanged to explore the effects of different nickel sources on catalytic performance. The experiment found that compared with Example 2, the catalytic activity increased slightly, the average particle size decreased slightly, the stability increased, and the activity decreased by 2% less than Example 2 after a certain period of time. This shows that different nickel sources have a certain effect on the performance of the catalyst.

[0068] Embodiment 6:

[0069] To explore the effect of different heating times in the reactor on the catalytic performance of doped non-precious metal platinum nanoparticles, the steps of Example 2 were repeated, and the heating time of the reactor was adjusted to 20 h.

[0070] Example 6 extended the heating time to 20 hours based on Example 2 to investigate the effect of reaction time on the performance of platinum nickel nanoparticles. The experiment found that after extending the reaction time, the catalytic activity decreased slightly, the average size of the nanoparticles increased slightly, and the stability decreased, indicating that under the same conditions, extending the reaction time may cause the nanoparticles to agglomerate, which is not conducive to improving the catalytic performance and stability of the nanoparticles.

[0071] Embodiment 7:

[0072] To explore the effect of different platinum salt concentrations on the catalytic performance of doped non-precious metal platinum nanoparticles, based on Example 2, the platinum salt concentration was increased to 1 mol / L to observe the effect of the platinum salt concentration on the catalytic performance of the platinum nanoparticles.

[0073] In Example 7, the concentration of platinum salt was increased to 1 mol / L, and other conditions were the same as in Example 2, in order to study the effect of platinum salt concentration on catalyst performance. The experiment found that the increase in platinum salt concentration resulted in slightly higher catalytic activity, significantly reduced average size of nanoparticles, improved stability, and activity decreased by only 2% after a certain period of time. This indicates that appropriately increasing the concentration of platinum salt is beneficial to maintaining high catalytic activity and stability of nanoparticles.

[0074] Embodiment 8:

[0075] To explore the effect of preparing inert nanobubbles by different methods on the catalytic performance of doped non-precious metal platinum nanoparticles, based on Example 1, step 4 was changed to circulating nitrogen in the form of nanobubbles through a micro-nano bubble generator during the oil bath heating process, so that the reaction liquid was always in a supersaturated state of inert nanobubbles. The effect of different gas preparation methods on the catalytic performance of platinum nanoparticles was observed.

[0076] In Example 8, nitrogen was circulated and bubbled in the form of nanobubbles through a micro-nano bubble generator, and other conditions were the same as in Example 1. The experiment found that the platinum nanoparticles doped with non-precious metals prepared in Example 8 had higher catalytic activity, a smaller average size of the nanoparticles, improved stability, and activity decreased by 4% after a certain period of time. This indicates that circulating and bubbled nitrogen in the form of nanobubbles through a micro-nano bubble generator can more fully mix the reaction solution, and the platinum nanoparticles have higher activity.

[0077] Embodiment 9:

[0078] The experimental steps refer to Example 2. After the oil bath reaction in step 5 is completed, the solution is naturally cooled to room temperature to obtain a nickel-doped platinum nanoparticle colloidal solution, which is then set aside for later use.

[0079] To configure the hydrogen concentration detection reagent to test the amount of hydrogen dissolved in hydrogen-rich water, the steps are as follows:

[0080] (1) Weigh 0.2 g of methylene blue and 100 mL of anhydrous ethanol, mix them, and ultrasonicate for 10 min to prepare a methylene blue ethanol solution.

[0081] (2) Take 4.5 mL of methylene blue ethanol solution, add 0.5 mL of nickel-doped platinum nanoparticle colloidal solution, and mix well to obtain a hydrogen concentration detection reagent.

[0082] (3) Take 1 mL of the hydrogen-rich water to be tested, drop it into the prepared hydrogen concentration detection reagent, and observe the color change speed of the reagent from blue to colorless to determine the catalytic activity of the prepared nickel-platinum nanoparticles.

[0083] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0084] In addition, it should be understood that although the present specification is described according to embodiments, not every embodiment contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation methods that those skilled in the art can understand.

Claims

1. A method for preparing platinum nanoparticles doped with non-precious metals, characterized in that: The following steps are involved: S1: preparing a platinum-containing precursor solution and a non-precious metal salt solution respectively, then gradually adding the non-precious metal salt solution to the platinum precursor solution, placing the mixture in an ultrasonic stirrer for mixing for 1 hour, and preparing a mixed solution containing platinum and non-precious metals; S2: gradually add reducing agent A and stabilizer to the above mixed solution, place in an ultrasonic stirrer and continue mixing for 1 hour to ensure that the reactants are fully dissolved; S3: pour the mixed solution in step S2 into a three-necked flask, place the flask in an oil bath, heat and stir, and control the temperature in the oil bath to heat at a constant temperature for a period of time; S4: During the oil bath heating process, sodium bicarbonate powder treated by microencapsulation technology is added to gradually release nano carbon dioxide bubbles so that the reaction solution is always in a nano bubble supersaturated state; S5: After the oil bath reaction is completed, the reducing agent B is added again, the reaction solution is poured into the reactor, and the reaction is continued for a period of time at a certain temperature; S6: The reactor is naturally cooled to room temperature to obtain a platinum nanocolloid solution doped with a non-precious metal; the nanoparticles are further separated by centrifugation or filtration, and the platinum nanoparticles doped with a non-precious metal are obtained after washing and drying; The concentration of the platinum-containing precursor solution in S1 is 0.01 to 5 mol / L, the concentration of the dissolved non-precious metal salt is 0.01 to 5 mol / L, the reducing agent A and the reducing agent B are at least one of sodium borohydride, lithium borohydride, ascorbic acid, diethylamine, ethanol or hydrogen; the non-precious metal salt is at least one of nickel, cobalt, iron, copper and zinc salts; the stabilizer is polyvinyl pyrrolidone.

2. The method for preparing platinum nanoparticles doped with non-precious metals according to claim 1, characterized in that: The non-precious metal salt is any one of nickel nitrate, nickel sulfate, nickel chloride and nickel acetate.

3. The method for preparing platinum nanoparticles doped with non-precious metals according to claim 1, characterized in that: The platinum precursor is one or two of chloroplatinic acid, potassium chloroplatinate, sodium chloroplatinate, ammonium chloroplatinate, potassium chloroplatinite, sodium chloroplatinite, ammonium chloroplatinite, and diammine dichloroplatinum.

4. The method for preparing platinum nanoparticles doped with non-precious metals according to claim 1, characterized in that: In step S1, the concentration ratio of the platinum precursor to the non-precious metal salt is between 1:1 and 1:

15.

5. The method for preparing platinum nanoparticles doped with non-precious metals according to claim 1, characterized in that: The temperature of the oil bath in S3 is between 60 and 120° C., and the heating time is between 0.3 and 5 h. The temperature of the reactor in S5 is between 60 and 120° C., and the heating time is between 6 and 24 h.

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