Preparation method of bimetallic nanomaterial and method for testing hydrogen sensing performance

Abstract

The application relates to the technical field of hydrogen sensing material preparation, and discloses a preparation method of bimetallic nanomaterial and a hydrogen sensing performance testing method. The method comprises the following steps: reacting a first noble metal precursor solution, a second noble metal precursor solution, a surfactant solution, an inorganic halide solution and a reducing agent solution; wherein the first noble metal is palladium, and the first noble metal and the second noble metal are different. The method is simple and easy to operate, and can prepare bimetallic nanoparticles with different morphologies such as layers, branches and mesopores in a solution through one-step synthesis (water phase reduction method).

Description

Technical Field

[0001] This invention relates to the field of hydrogen sensing material preparation technology, specifically to a method for preparing bimetallic nanomaterials and a method for testing hydrogen sensing performance. Background Technology

[0002] At room temperature (RT), palladium (Pd) can reversibly react with H2, catalytically dissociating hydrogen into hydrogen atoms to form palladium hydride (PdHx), which has a higher resistivity than Pd. Quantitative detection of H2 can be achieved by detecting the resistance signal from a Pd-based sensor. However, single palladium metal often exhibits poor hydrogen sensing response and slow reaction kinetics, even for hydrogen sensors based on nanoscale Pd-based hydrogen-sensitive materials, where response and recovery speeds remain insufficient. Compared to single metals, bimetallic nanoparticles exhibit superior sensing performance due to synergistic effects between the metals. Therefore, introducing a second metal to prepare bimetallic nanoparticles to further improve sensing performance is the most effective method.

[0003] The main methods for preparing Pd-based nanoparticles include electrodeposition, template method, and chemical reduction method. Electrodeposition suffers from poor reproducibility and impure product composition, while the template method requires pre-preparation or post-removal template processes, making it cumbersome. In contrast, the chemical reduction method is simple to operate, has good reproducibility, and can produce products with uniform morphology and size. Currently, the seed method, a two-step method, is commonly used to prepare palladium nanoparticles. This method not only requires the pre-preparation of palladium nanoparticles with a specific morphology as seed crystals, but also necessitates the addition of a morphology control agent in the subsequent reaction to guide or restrict the growth of specific crystal faces, thus allowing the continued growth of palladium nanoparticles with different crystal faces based on the original morphology. However, some special morphologies, such as dendritic and mesoporous structures, are often prepared using a high-temperature two-step method (seed method). This involves pre-preparing Pd nanoparticles with specific crystal orientations, then adding a certain amount of centrifuged and cleaned Pd particles to a solution containing a second metal precursor, using the precursor as a seed crystal to guide the growth of Pd particles on its surface. The seed method is not only cumbersome, but there are also few reports on one-step synthesis methods for bimetallic nanoparticles with special morphologies.

[0004] Therefore, there is an urgent need to provide a simple and versatile method for preparing Pd-based bimetallic hydrogen-sensitive materials. Summary of the Invention

[0005] The purpose of this invention is to overcome the problems of existing technologies that typically employ a two-step method to prepare palladium-based bimetallic nanomaterials with special morphologies. This method is cumbersome, has poor repeatability, results in non-uniform size, and lacks morphological control. The invention provides a method for preparing bimetallic nanomaterials and testing their hydrogen sensing performance. The proposed method is simple and easy to operate, and can prepare layered, dendritic, and mesoporous bimetallic nanoparticles with different morphologies through a one-step synthesis method (aqueous phase reduction method) in solution.

[0006] To achieve the above objectives, the present invention provides a method for preparing bimetallic nanomaterials, the method comprising: reacting a first noble metal precursor solution, a second noble metal precursor solution, a surfactant solution, an inorganic halide solution, and a reducing agent solution;

[0007] The first precious metal is palladium, and the first and second precious metals are different.

[0008] Preferably, the molar ratio of the first precious metal precursor (calculated as the first precious metal) to the second precious metal precursor (calculated as the second precious metal) is 1-10:1, more preferably 2-4:1.

[0009] Preferably, the first noble metal precursor solution is selected from one or more of palladium acetylacetone solution, palladium chloride solution, and palladium nitrate solution.

[0010] Preferably, the concentration of the first noble metal precursor solution is 0.005M-0.02M.

[0011] Preferably, the second noble metal precursor solution is selected from one or more of chloroplatinic acid solution, chloroiridium acid solution, chlororhodium acid solution, chlororuthenic acid solution, chloroauric acid solution, chlorosilyl acid solution and chloroacetic acid solution, and is preferably chloroplatinic acid solution.

[0012] Preferably, the concentration of the second noble metal precursor solution is 0.005M-0.02M.

[0013] Preferably, the molar ratio of the first precious metal precursor, surfactant, inorganic halide and reducing agent, calculated as the first precious metal, is 0.5-1.5:10:1-8:1.

[0014] Preferably, the surfactant solution is selected from one or more of CTAB solution, CTAC solution, PVP solution, CPC solution and SDBS solution.

[0015] Preferably, the concentration of the surfactant solution is 0.01M-0.05M.

[0016] Preferably, the inorganic halide solution is selected from one or more of potassium fluoride solution, potassium chloride solution, potassium bromide solution, potassium iodide solution, sodium fluoride solution, sodium chloride solution, sodium bromide solution, and sodium iodide solution.

[0017] Preferably, the concentration of the inorganic halide solution is 20-160 mM.

[0018] Preferably, the reducing agent solution is selected from one or more of ascorbic acid solution, sodium borohydride solution and sodium hypophosphite solution.

[0019] Preferably, the concentration of the reducing agent solution is 0.01M-0.06M.

[0020] Preferably, the reaction conditions include a temperature of 50-100℃ and a time of 1-12h.

[0021] A second aspect of the present invention provides a bimetallic nanomaterial prepared by the method described above.

[0022] Preferably, the bimetallic nanomaterial contains a first noble metal and a second noble metal, wherein the first noble metal is palladium, and the first noble metal and the second noble metal are different and exist in an alloy form.

[0023] Preferably, the molar ratio of the first noble metal to the second noble metal is 1-10:1, more preferably 2-4:1.

[0024] Preferably, the second precious metal is selected from platinum, iridium, rhodium, ruthenium, gold, or silver, with platinum being the most preferred.

[0025] Preferably, the particle size of the bimetallic nanomaterial is 50-500 nm.

[0026] A third aspect of the present invention provides a bimetallic nanomaterial prepared by the method described above, or the application of the bimetallic nanomaterial described above as a hydrogen-sensitive material.

[0027] A fourth aspect of the present invention provides a method for testing the performance of a hydrogen sensing material, the method comprising: placing a hydrogen-sensitive material in a sealed device, introducing a mixed gas containing hydrogen and a protective gas to react, and testing the resistance at different reaction times; wherein the hydrogen-sensitive material contains a bimetallic nanomaterial prepared by the method described above or the bimetallic nanomaterial described above.

[0028] Preferably, the concentration of hydrogen in the mixed gas is 0.02-2% by volume.

[0029] Preferably, the reaction conditions include: a temperature of 15-30°C and a time of 100-4000 s.

[0030] Compared with the prior art, the present invention has at least the following advantages:

[0031] (1) This invention proposes a simple, easy-to-operate, and morphology-controllable one-step synthesis method (aqueous phase reduction method) for preparing bimetallic nanomaterials in aqueous solution. It only requires the bimetallic precursor to coexist in the aqueous reaction solution, without the need for pre-preparation of seed crystals. By changing the type of halide added, bimetallic nanoparticles with different morphologies such as layered, dendritic, and mesoporous can be obtained. At the same time, this method is environmentally friendly and uses inexpensive raw materials.

[0032] (2) The present invention provides a specific bimetallic nanomaterial containing palladium and another noble metal, and the two noble metals exist in the form of an alloy. The bimetallic nanomaterial with this feature has a fast response time to hydrogen and has strong mechanical strength, hygrothermal stability and chemical stability.

[0033] (3) The bimetallic nanomaterials prepared in this invention are used as hydrogen-sensitive materials. They have a fast response time to hydrogen, strong mechanical strength, damp heat stability and chemical stability, and can quickly detect and respond to hydrogen leakage in the environment, thereby ensuring their safe use. Attached Figure Description

[0034] Figure 1 These are SEM images of the material prepared in Example 1;

[0035] Figure 2 These are SEM images of the material prepared in Example 34;

[0036] Figure 3 This is the resistance curve of the material in Example 1 as a function of time. Detailed Implementation

[0037] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0038] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0039] The method for preparing bimetallic nanomaterials provided by the present invention includes: reacting a first noble metal precursor solution, a second noble metal precursor solution, a surfactant solution, an inorganic halide solution, and a reducing agent solution;

[0040] The first noble metal is palladium, meaning the first noble metal precursor solution is a palladium precursor solution. The first noble metal and the second noble metal are different.

[0041] The preparation method provided by this invention is simple and easy to operate. It only requires mixing a first noble metal precursor solution, a second noble metal precursor solution, a surfactant solution, an inorganic halide solution, and a reducing agent solution, followed by a one-step aqueous phase reduction reaction to obtain the target product, without the need for pre-preparation of seed crystals. By changing the type of halide, various palladium-based bimetallic nanoparticle materials with controllable morphology and uniform size can be prepared.

[0042] In this invention, there is no specific order in which the first noble metal precursor solution, the second noble metal precursor solution, the surfactant solution, the inorganic halide solution, and the reducing agent solution are mixed, as long as they can react normally.

[0043] In a specific embodiment, the method includes: mixing a first noble metal precursor solution, a second noble metal precursor solution, a surfactant solution, and an inorganic halide solution; stirring in a water bath at 60-100°C; then adding a reducing agent solution and mixing; and allowing the mixture to stand before reacting. In this invention, all mixing processes are carried out under stirring conditions.

[0044] In a specific embodiment, the reaction temperature can be 50-100℃, for example 50℃, 60℃, 70℃, 80℃, 90℃ or 100℃, preferably 90℃; the reaction time can be 1-12h, for example 1h, 2h, 4h, 6h, 8h, 10h or 12h, preferably 6h.

[0045] In this invention, the reaction can be carried out in a common heating device, specifically in a water bath.

[0046] In the method described in this invention, to obtain pure and dry bimetallic nanomaterials, the reaction product is centrifuged after the reaction is completed, and then the solid product is washed and dried. In a specific embodiment, the washing includes alternating washing with deionized water and ethanol several times.

[0047] In a specific implementation, the molar ratio of the first precious metal precursor, calculated based on the first precious metal element, to the second precious metal precursor, calculated based on the second precious metal element, can be 1-10:1.

[0048] In order to improve the hydrogen sensing performance of the prepared bimetallic nanomaterials and shorten the response time to hydrogen, in a preferred embodiment, the molar ratio of the first noble metal precursor (calculated as the first noble metal element) to the second noble metal precursor (calculated as the second noble metal element) is 2-4:1.

[0049] In this invention, the first noble metal precursor solution can be any palladium precursor solution well-known in the art, as long as it can provide palladium for the bimetallic nanomaterial. In specific embodiments, the first noble metal precursor solution can be selected from one or more of palladium acetylacetone solution, palladium chloride solution, and palladium nitrate solution. In a preferred embodiment, the first noble metal precursor solution is a palladium chloride solution.

[0050] In a specific embodiment, the palladium precursor solution is prepared by mixing the palladium precursor with a hydrochloric acid solution.

[0051] In this invention, the concentration of the first noble metal precursor solution (palladium precursor solution) can be a concentration conventionally prepared in the art, without particular limitation. In a specific embodiment, the concentration of the first noble metal precursor solution is 0.005M-0.02M, preferably 0.01M. Herein, "M" refers to the unit mol / L.

[0052] In the method described in this invention, the second noble metal precursor solution can be a noble metal precursor other than palladium precursor commonly used in the art.

[0053] In a specific embodiment, the second noble metal precursor solution is selected from one or more of chloroplatinic acid solution, chloroiridium acid solution, chlororhodium acid solution, chlororuthenic acid solution, chloroauric acid solution, chlorosilyl acid solution, and chloroaluminic acid solution.

[0054] In order to improve the hydrogen sensing performance of the prepared bimetallic nanomaterials and shorten the response time to hydrogen, in a preferred embodiment, the second noble metal precursor solution is a chloroplatinic acid solution.

[0055] In this invention, the concentration of the second noble metal precursor solution can be a concentration conventionally prepared in the art, without particular limitation. In a specific embodiment, the concentration of the second noble metal precursor solution can be 0.005M-0.02M, preferably 0.01M.

[0056] In a specific embodiment, the second noble metal precursor solution can be an aqueous solution prepared according to conventional methods in the art, as long as it can provide a second noble metal other than palladium for the bimetallic nanoparticle material.

[0057] In this invention, the amounts of surfactant, inorganic halide, and reducing agent have a certain influence on the hydrogen sensing performance of the prepared bimetallic nanomaterial. In a specific embodiment, the molar ratio of the first noble metal precursor, surfactant, inorganic halide, and reducing agent (calculated as the first noble metal) can be 0.5-1.5:10:1-8:1.

[0058] In this invention, the surfactant solution can be an aqueous solution prepared with water to act on the surfactant. In specific embodiments, the surfactant solution can be selected from one or more of CTAB (hexadecyltrimethylammonium bromide) solution, CTAC (hexadecyltrimethylammonium chloride) solution, PVP (polyvinylpyrrolidone) solution, CPC (hexadecylpyridine chloride) solution, and SDBS (sodium dodecylbenzenesulfonate) solution, preferably CPC (hexadecylpyridine chloride) solution.

[0059] In this invention, the concentration of the surfactant solution is not limited, as long as it meets the aforementioned ratio of raw materials. In a specific embodiment, the concentration of the surfactant solution can be 0.01M-0.05M.

[0060] In the method described in this invention, various bimetallic nanomaterials with controllable morphology and uniform size can be prepared by changing the type of inorganic halide solution. The morphology of the nanomaterials can be layered, dendritic, or mesoporous, etc. In this invention, the type of inorganic halide solution is not limited and can be any conventional choice in the art, such as an aqueous solution. In specific embodiments, the inorganic halide solution can be selected from one or more of potassium fluoride solution, potassium chloride solution, potassium bromide solution, potassium iodide solution, sodium fluoride solution, sodium chloride solution, sodium bromide solution, and sodium iodide solution, preferably one or more of potassium chloride solution, potassium bromide solution, and potassium iodide solution.

[0061] In this invention, the size of the prepared bimetallic nanomaterials can be controlled by changing the concentration of the inorganic halide solution. In a specific embodiment, the concentration of the halide solution can be 20-160 mM, for example 20 mM, 40 mM, 60 mM, 80 mM, 100 mM, 120 mM, 140 mM or 160 mM, preferably 60 mM.

[0062] In this invention, the reducing agent solution can be an aqueous solution prepared according to conventional methods in the art; the type of reducing agent solution is not limited, as long as it can reduce palladium and another noble metal. In specific embodiments, the reducing agent solution can be selected from one or more of ascorbic acid solution, sodium borohydride solution, and sodium hypophosphite solution, preferably ascorbic acid solution.

[0063] In a specific embodiment, the concentration of the reducing agent solution can be 0.01M-0.06M, for example 0.01M, 0.015M, 0.02M, 0.025M, 0.03M, 0.035M, 0.04M, 0.045M, 0.05M, 0.055M or 0.06M.

[0064] In this invention, in order to improve the reduction effect of the reducing agent solution, in a preferred embodiment, the reducing agent solution is a freshly prepared reducing agent solution.

[0065] The preparation process provided by this invention is simple, has good stability, and is easy to apply in large-scale production.

[0066] A second aspect of the present invention provides a bimetallic nanomaterial prepared by the method described above. The bimetallic nanomaterial contains a first noble metal and a second noble metal, wherein the first noble metal is palladium, and the first and second noble metals are different and exist in an alloy form.

[0067] The inventors of this application have discovered through research that bimetallic nanomaterials containing a first noble metal palladium and a second noble metal have a fast response time to hydrogen, and possess strong mechanical strength, damp heat stability, and chemical stability. As hydrogen-sensitive materials, they can quickly detect and respond to hydrogen leaks in the environment, thereby ensuring their safe use.

[0068] In a specific implementation, the molar ratio of the first noble metal to the second noble metal can be 1-10:1.

[0069] In a preferred embodiment, in order to improve the hydrogen sensing performance of the bimetallic nanomaterial, the molar ratio of the first noble metal to the second noble metal is 2-4:1.

[0070] In this invention, the bimetallic nanomaterial is a nanoparticle with uniform size. Characterization shows that the nanoparticle can have various morphologies such as layered, dendritic, and mesoporous.

[0071] In a specific embodiment, the particle size of the bimetallic nanomaterial can be 50-500 nm.

[0072] In this invention, the second precious metal can be a conventional choice in the art. In a specific embodiment, the second precious metal can be selected from platinum, iridium, rhodium, ruthenium, gold, or silver.

[0073] In a preferred embodiment, to improve the hydrogen sensing performance of the bimetallic nanomaterial, the second noble metal is preferably platinum.

[0074] A third aspect of the present invention provides a bimetallic nanomaterial prepared by the method described above, or the application of the bimetallic nanomaterial described above as a hydrogen-sensitive material.

[0075] The bimetallic nanomaterials provided by this invention are novel hydrogen-sensitive materials. Compared with metal oxide-type hydrogen-sensitive materials, they do not require heating, have low power consumption, good selectivity, and fast response speed.

[0076] A fourth aspect of the present invention provides a method for testing the performance of a hydrogen sensing material, the method comprising: placing a hydrogen-sensitive material in a sealed device, introducing a mixed gas containing hydrogen and a protective gas to react, and testing the resistance at different reaction times; wherein the hydrogen-sensitive material contains a bimetallic nanomaterial prepared by the method described above or the bimetallic nanomaterial described above.

[0077] In a specific implementation, a certain mass of bimetallic nanomaterials can be placed in an agate mortar, terpineol can be added, and the mixture can be thoroughly ground into a slurry and then uniformly coated onto a ceramic tube to prepare an element. The element is then placed in a sealed device for testing.

[0078] In the method for testing the hydrogen sensing performance of the present invention, the type of sealing device is not limited, as long as it is a sealed device that can allow gas to pass through, such as a sealed chamber.

[0079] In a specific embodiment, the concentration of hydrogen in the mixed gas can be 0.02-2 vol%, for example, 0.02 vol%, 0.05 vol%, 0.08 vol%, 0.1 vol%, 0.2 vol%, 0.3 vol%, 0.4 vol%, 0.5 vol%, 0.6 vol%, 0.7 vol%, 0.8 vol%, 0.9 vol%, 1 vol%, 1.2 vol%, 1.4 vol%, 1.5 vol%, 1.6 vol%, 1.8 vol%, or 2 vol%.

[0080] According to the present invention, the protective gas can be a conventional choice in the art; specifically, the protective gas can be nitrogen and / or air.

[0081] In the hydrogen sensing performance testing method of the present invention, in a specific embodiment, the reaction conditions include: a temperature of 15-30℃ (room temperature); and a time of 100-4000s, preferably 400-2000s.

[0082] In this invention, the instrument used for hydrogen sensing performance testing is the CGS-8 intelligent gas-sensitive analysis system from Elitet Technology Co., Ltd.

[0083] The hydrogen-sensitive material (hydrogen sensing material) provided by this invention directly addresses the leakage monitoring and safety issues of hydrogen, a new generation of clean energy. It can quickly detect and respond to hydrogen leaks in the environment at room temperature, thereby ensuring its safe use. It can be used in hydrogen production, hydrogen refueling, hydrogen storage and other hydrogen usage processes.

[0084] The present invention will be described in detail below through examples, but the scope of protection of the present invention is not limited thereto. Unless otherwise specified, all reagents used in the following examples and comparative examples are commercially available products.

[0085] In the embodiments and comparative examples of the present invention, the preparation methods of the surfactant solution, inorganic halide solution, second noble metal precursor solution, and reducing agent solution are as follows: the surfactant, inorganic halide, second noble metal precursor, and reducing agent are respectively mixed with water; the preparation method of the palladium precursor solution is as follows: the palladium precursor is mixed with dilute hydrochloric acid with a concentration of 37%.

[0086] Example 1

[0087] (1) Add 10 mL of 0.02 M CPC surfactant solution to a glass bottle, then add 2 mL of 0.01 M palladium precursor (PdCl2) solution, followed by 1 mL of 20 mM inorganic halide (potassium chloride) solution and 1 mL of 0.01 M platinum precursor (H2PtCl2). 6· A solution of 6H2O, wherein the molar ratio of palladium precursor to platinum precursor, calculated as palladium, can be 2:1;

[0088] (2) Place the glass bottle containing the above mixed solution in a water bath at 80°C and stir. After the solution becomes clear, add 1 mL of freshly prepared 0.02 M reducing agent (ascorbic acid) solution. Continue stirring for 2 minutes and let stand for 10 minutes. Then continue to react at 80°C for 6 hours. The molar ratio of the amount of palladium precursor, surfactant, inorganic halide and reducing agent, calculated as palladium element, can be 1:10:1:1.

[0089] (3) After the reaction is completed, the reaction product is cooled and centrifuged. Then the obtained solid product is washed three times with deionized water and ethanol alternately. After each washing, it is centrifuged and dried to obtain the reaction product. The drying temperature is 60℃ and the drying time is 24h.

[0090] SEM images of the material prepared in Example 1 are as follows: Figure 1 As shown, from Figure 1 It can be seen that the main morphology is spherical or rod-shaped.

[0091] Example 2

[0092] The method was carried out according to Example 1, except that the palladium precursor (PdCl2) solution and the platinum precursor (H2PtCl) were used. 6· The concentration of the 6H2O solution is replaced with 0.005M. The molar ratio of palladium precursor to platinum precursor (calculated as palladium element) can be 2:1. The molar ratio of palladium precursor, surfactant, inorganic halide and reducing agent (calculated as palladium element) can be 0.5:10:1:1.

[0093] Example 3

[0094] The method was carried out according to Example 1, except that the palladium precursor (PdCl2) solution and the platinum precursor (H2PtCl) were used. 6· The concentration of the 6H2O solution is replaced with 0.015M. The molar ratio of palladium precursor to platinum precursor (calculated as palladium) can be 2:1. The molar ratio of palladium precursor, surfactant, inorganic halide and reducing agent (calculated as palladium) can be 3:20:2:2.

[0095] Example 4

[0096] The method was carried out according to Example 1, except that the palladium precursor (PdCl2) solution and the platinum precursor (H2PtCl) were used. 6· The concentration of the 6H2O solution is changed to 0.02M. The molar ratio of palladium precursor to platinum precursor (calculated as palladium element) can be 2:1. The molar ratio of palladium precursor, surfactant, inorganic halide and reducing agent (calculated as palladium element) can be 2:10:1:1.

[0097] Example 5

[0098] The method was carried out in accordance with Example 1, except that the surfactant solution was replaced with a CTAB solution of the same concentration and volume.

[0099] Example 6

[0100] The method was carried out in accordance with Example 1, except that the surfactant solution was replaced with a CTAC solution of the same concentration and volume.

[0101] Example 7

[0102] The method was carried out in accordance with Example 1, except that the surfactant solution was replaced with a PVP solution of the same concentration and volume.

[0103] Example 8

[0104] The method was carried out in accordance with Example 1, except that the surfactant solution was replaced with an SDBS solution of the same concentration and volume.

[0105] Example 9

[0106] The method of Example 1 is implemented, except that the 20 mM potassium chloride solution is replaced with a 60 mM potassium chloride solution, and the molar ratio of the palladium precursor, surfactant, inorganic halide and reducing agent (calculated as palladium element) can be 1:10:3:1.

[0107] Example 10

[0108] The method of Example 1 is implemented, except that the 20 mM potassium chloride solution is replaced with a 100 mM potassium chloride solution, and the molar ratio of the palladium precursor, surfactant, inorganic halide and reducing agent (calculated as palladium element) can be 1:10:5:1.

[0109] Example 11

[0110] The method of Example 1 is implemented, except that the 20 mM potassium chloride solution is replaced with a 160 mM potassium chloride solution, and the molar ratio of the palladium precursor, surfactant, inorganic halide and reducing agent (calculated as palladium element) can be 1:10:8:1.

[0111] Example 12

[0112] The method was carried out in accordance with Example 1, except that the 20 mM potassium chloride solution was replaced with a 20 mM potassium bromide solution.

[0113] Example 13

[0114] The method of Example 1 is followed, except that the 20 mM potassium chloride solution is replaced with a 60 mM potassium bromide solution, and the molar ratio of the palladium precursor, surfactant, inorganic halide and reducing agent (calculated as palladium) can be 1:10:3:1.

[0115] Example 14

[0116] The method of Example 1 is followed, except that the 20 mM potassium chloride solution is replaced with a 100 mM potassium bromide solution, and the molar ratio of the palladium precursor, surfactant, inorganic halide and reducing agent (calculated as palladium) can be 1:10:5:1.

[0117] Example 15

[0118] The method of Example 1 is followed, except that the 20 mM potassium chloride solution is replaced with a 160 mM potassium bromide solution, and the molar ratio of the palladium precursor, surfactant, inorganic halide and reducing agent (calculated as palladium) can be 1:10:8:1.

[0119] Example 16

[0120] The method was carried out in accordance with Example 1, except that the 20 mM potassium chloride solution was replaced with a 20 mM potassium iodide solution.

[0121] Example 17

[0122] The method of Example 1 is followed, except that the 20 mM potassium chloride solution is replaced with a 60 mM potassium iodide solution, and the molar ratio of the palladium precursor, surfactant, inorganic halide and reducing agent (calculated as palladium) can be 1:10:3:1.

[0123] Example 18

[0124] The method of Example 1 is followed, except that the 20 mM potassium chloride solution is replaced with a 100 mM potassium iodide solution, and the molar ratio of the palladium precursor, surfactant, inorganic halide and reducing agent (calculated as palladium element) can be 1:10:5:1.

[0125] Example 19

[0126] The method of Example 1 is followed, except that the 20 mM potassium chloride solution is replaced with a 160 mM potassium iodide solution, and the molar ratio of the palladium precursor, surfactant, inorganic halide and reducing agent (calculated as palladium element) can be 1:10:8:1.

[0127] Example 20

[0128] The method was implemented according to Example 1, except that the reaction continued at 80°C for 6 hours in step (2) was replaced with the reaction continued at 60°C for 6 hours.

[0129] Example 21

[0130] The method was implemented according to Example 1, except that the reaction continued at 80°C for 6 hours in step (2) was replaced with the reaction continued at 90°C for 6 hours.

[0131] Example 22

[0132] The method was carried out according to Example 1, except that the reaction continued at 80°C for 6 hours in step (2) was replaced with the reaction continued at 100°C for 6 hours.

[0133] Example 23

[0134] The method was implemented according to Example 1, except that the reaction continued at 80°C for 6 hours in step (2) was replaced with the reaction continued at 80°C for 2 hours.

[0135] Example 24

[0136] The method was implemented according to Example 1, except that the reaction continued at 80°C for 6 hours in step (2) was replaced with the reaction continued at 80°C for 9 hours.

[0137] Example 25

[0138] The method was implemented according to Example 1, except that the reaction continued at 80°C for 6 hours in step (2) was replaced with the reaction continued at 80°C for 12 hours.

[0139] Example 26

[0140] The method of Example 1 is implemented, except that the drying temperature of 60°C and the drying time of 24h in step (3) are replaced with a drying temperature of 40°C and a drying time of 24h.

[0141] Example 27

[0142] The method of Example 1 is implemented, except that the drying temperature of 60°C and the drying time of 24h in step (3) are replaced with a drying temperature of 80°C and a drying time of 24h.

[0143] Example 28

[0144] The method is implemented according to Example 1, except that the drying temperature of 60°C and the drying time of 24h in step (3) are replaced with a drying temperature of 100°C and a drying time of 24h.

[0145] Example 29

[0146] The method of Example 1 is implemented, except that the drying temperature of 60°C and the drying time of 24h in step (3) are replaced with a drying temperature of 60°C and a drying time of 12h.

[0147] Example 30

[0148] The method of Example 1 is implemented, except that the drying temperature of 60°C and the drying time of 24h in step (3) are replaced with a drying temperature of 60°C and a drying time of 36h.

[0149] Example 31

[0150] The method was carried out according to Example 1, except that the precursor chloroplatinic acid (H2PtCl) was used. 6· Replace 6H2O with chloroiridium acid.

[0151] Example 32

[0152] The method was carried out according to Example 1, except that the precursor chloroplatinic acid (H2PtCl) was used. 6· (6H2O) is replaced with chlororhodium acid.

[0153] Example 33

[0154] The method was carried out according to Example 1, except that the precursor chloroplatinic acid (H2PtCl) was used.6· (6H2O) is replaced with chlororuthenic acid.

[0155] Example 34

[0156] The method was carried out according to Example 1, except that the precursor chloroplatinic acid (H2PtCl) was used. 6· Replace 6H2O with chloroauric acid.

[0157] SEM images of the material prepared in Example 34 are as follows: Figure 2 As shown, from Figure 2 It can be seen that the main morphology is spherical or polyhedral.

[0158] Example 35

[0159] The method was carried out according to Example 1, except that the precursor chloroplatinic acid (H2PtCl) was used. 6· Replace 6H2O with chlorosilicic acid.

[0160] Example 36

[0161] The method was carried out according to Example 1, except that the precursor chloroplatinic acid (H2PtCl) was used. 6· Replace 6H2O with chloroosmium acid.

[0162] Comparative Example 1

[0163] The method was carried out according to Example 1, except that no platinum precursor (H2PtCl) was added. 6· (6H2O) solution.

[0164] Test Example 1

[0165] The molar ratio of palladium to the second noble metal in the materials prepared in the examples and comparative examples was characterized and calculated by inductively coupled plasma mass spectrometry (ICP-MS), and the nanoscale size of the materials prepared in the examples and comparative examples was characterized and statistically analyzed by SEM. The results are shown in Table 1.

[0166] Table 1

[0167]

[0168]

[0169]

[0170] Test Example 2

[0171] The materials prepared in the examples and comparative examples were used as hydrogen-sensitive materials for hydrogen sensing performance testing. The instrument used was the CGS-8 intelligent gas-sensitive analysis system from Elite Technologies Inc. The test method included: placing the materials prepared in the examples and comparative examples into sealed chambers, and introducing a mixture of dry hydrogen and air to react, wherein the concentration of hydrogen was 1% by volume. All tests were measured at room temperature (25°C), and the resistance change curves were obtained. The response time and recovery time were calculated based on the resistance change curves. The results are shown in Table 2.

[0172] The resistance curve of the material in Example 1 as a function of time is shown below. Figure 3 As shown.

[0173] The response time is the time required for the resistance of the target gas to return to 90% of its initial value after contact with the target gas.

[0174] Table 2

[0175]

[0176]

[0177]

[0178] As can be seen from the results in Table 2, the material prepared by the method described in this invention has excellent sensing performance and a fast response speed to hydrogen.

[0179] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for preparing bimetallic nanomaterials, characterized in that, The method includes reacting a first noble metal precursor solution, a second noble metal precursor solution, a surfactant solution, an inorganic halide solution, and a reducing agent solution; The first precious metal is palladium, and the first and second precious metals are different.

2. The method according to claim 1, characterized in that, The molar ratio of the first precious metal precursor (calculated as the first precious metal) to the second precious metal precursor (calculated as the second precious metal) is 1-10:1, preferably 2-4:

1.

3. The method according to claim 1 or 2, characterized in that, The first noble metal precursor solution is selected from one or more of palladium acetylacetone solution, palladium chloride solution, and palladium nitrate solution; Preferably, the concentration of the first noble metal precursor solution is 0.005M-0.02M.

4. The method according to any one of claims 1-3, characterized in that, The second noble metal precursor solution is selected from one or more of chloroplatinic acid solution, chloroiridium acid solution, chlororhodium acid solution, chlororuthenic acid solution, chloroauric acid solution, chlorosilyl acid solution and chloroacetic acid solution, preferably chloroplatinic acid solution; Preferably, the concentration of the second noble metal precursor solution is 0.005M-0.02M.

5. The method according to any one of claims 1-4, characterized in that, The molar ratio of the first precious metal precursor, surfactant, inorganic halide and reducing agent, calculated as the first precious metal, is 0.5-1.5:10:1-8:

1.

6. The method according to any one of claims 1-5, characterized in that, The surfactant solution is selected from one or more of CTAB solution, CTAC solution, PVP solution, CPC solution and SDBS solution; Preferably, the concentration of the surfactant solution is 0.01M-0.05M.

7. The method according to any one of claims 1-6, characterized in that, The inorganic halide solution is selected from one or more of potassium fluoride solution, potassium chloride solution, potassium bromide solution, potassium iodide solution, sodium fluoride solution, sodium chloride solution, sodium bromide solution, and sodium iodide solution; Preferably, the concentration of the inorganic halide solution is 20-160 mM.

8. The method according to any one of claims 1-7, characterized in that, The reducing agent solution is selected from one or more of ascorbic acid solution, sodium borohydride solution and sodium hypophosphite solution; Preferably, the concentration of the reducing agent solution is 0.01M-0.06M.

9. The method according to any one of claims 1-8, characterized in that, The reaction conditions include a temperature of 50-100℃ and a time of 1-12h.

10. Bimetallic nanomaterials prepared by the method according to any one of claims 1-9.

11. The bimetallic nanomaterial according to claim 10, characterized in that, The bimetallic nanomaterial contains a first noble metal and a second noble metal, wherein the first noble metal is palladium, and the first noble metal and the second noble metal are different and exist in an alloy form. Preferably, the molar ratio of the first noble metal to the second noble metal is 1-10:1, more preferably 2-4:1; Preferably, the second precious metal is selected from platinum, iridium, rhodium, ruthenium, gold, or silver, with platinum being the most preferred.

12. The bimetallic nanomaterial according to claim 10 or 11, characterized in that, The particle size of the bimetallic nanomaterial is 50-500 nm.

13. The application of the bimetallic nanomaterial prepared by the method according to any one of claims 1-9 or the bimetallic nanomaterial according to any one of claims 10-12 as a hydrogen-sensitive material.

14. A method for testing the performance of a hydrogen sensor, characterized in that, The method includes: placing a hydrogen-sensitive material in a sealed device, introducing a mixed gas containing hydrogen and a protective gas to react, and testing the resistance at different reaction times; wherein the hydrogen-sensitive material contains a bimetallic nanomaterial prepared by the method of any one of claims 1-9 or a bimetallic nanomaterial as described in any one of claims 10-12.

15. The method according to claim 14, characterized in that, The concentration of hydrogen in the mixed gas is 0.02-2% by volume; Preferably, the reaction conditions include: a temperature of 15-30°C and a time of 100-4000 s.

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