Core-shell structure Ru-Pt / C nano electrocatalyst and application thereof

Abstract

The invention provides a core-shell structure Ru (at) Pt / C nano electrocatalyst and application thereof, and relates to the technical field of nano electrocatalyst material preparation, and the core-shell structure Ru (at) Pt / C nano electrocatalyst is prepared by the following steps: S1, uniformly mixing and grinding a carbon carrier and ruthenium salt to obtain a first mixture; s2, the first mixture is placed in a container and subjected to microwave heating for a period of time, and black powder is obtained; s3, adding platinum salt and a reducing agent into the black powder, grinding and uniformly mixing to obtain a second mixture; s4, placing the second mixture in a container, adding water, and then performing microwave heating for a period of time; and centrifuging, washing and drying the obtained product to obtain the catalyst. The synthesis method of the nanometer water electrolysis hydrogen evolution catalyst is simple and convenient, the requirement for equipment is low, and the prepared nanometer water electrolysis hydrogen evolution catalyst is excellent in performance.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of catalyst material preparation, in particular to a Ru@Pt / C nanometer electrocatalyst with a core-shell structure and application thereof. BACKGROUND

[0002] With the development of economy and the rise of industry, the input of a large amount of energy has caused a large amount of resource consumption and environmental pollution. Hydrogen energy, as an effective method to cope with fossil crisis and climate change, has attracted widespread attention from researchers. Among them, the water electrolysis hydrogen production equipment is simple in structure, low in cost and can be used for large-scale production. Alkaline water electrolysis hydrogen production is an important part of the water electrolysis hydrogen evolution process, which has large capacity, high yield and good stability. However, with the increase of electrolyte pH value, the reaction rate of the water electrolysis hydrogen evolution reaction process gradually decreases, the reaction kinetics is slow, the energy consumption is high, and the cost is expensive. Therefore, developing a low-cost and high-efficiency alkaline HER catalyst is the key to improving production efficiency.

[0003] In the process of water electrolysis hydrogen production, finding a low-cost and high-efficiency alkaline HER (alkaline hydrogen evolution reaction) catalyst is the key to improving production efficiency. At present, platinum-based catalysts are still the best HER catalysts, but due to the high price and limited storage of platinum, they cannot meet the demand of large-scale application. In order to solve this problem, researchers have proposed two technical routes.

[0004] The first technical route is to design non-platinum alkaline hydrogen evolution reaction electrocatalysts. Researchers have made significant progress in metal phosphides, metal sulfides, metal oxides and non-noble metal alloys, but most non-platinum electrocatalysts still have a large gap compared with platinum-based catalysts.

[0005] The second technical route focuses on the research of low-platinum electrocatalysts. The common preparation strategies include precise control of the morphology and composition of the catalyst, such as introducing a carrier or forming an alloy structure of platinum and transition metals. Carbon materials are the most widely used carriers at present, which have good stability, high electrical conductivity and active area, such as carbon black, mesoporous carbon, carbon nanotubes and graphene.

[0006] Among noble metals, Ru is a low-cost noble metal, and the bond between Ru and hydrogen atoms has a low adsorption energy, and the price is relatively low, so it is considered as the first choice to replace platinum-based catalysts. However, the currently disclosed various PtRu / C nanometer catalyst preparation methods have the problems of poor dispersity and insufficient catalytic performance. Therefore, a simple and effective preparation process is urgently needed to prepare a composite electrocatalyst with Ru core and Pt shell core-shell structure, so as to reduce the amount of Pt and improve the activity and stability of the alkaline hydrogen evolution reaction. SUMMARY

[0007] The application provides a preparation method of a core-shell structure Ru@Pt / C nano electrocatalyst. The method uses a microwave reduction method to successfully prepare Ru@Pt / C by using a ruthenium salt, a platinum salt, a carbon carrier and a reducing agent as raw materials, so as to effectively reduce the amount of platinum, improve the activity and durability of the hydrogen evolution reaction. Compared with the prior art, the nano Ru@Pt / C catalyst prepared by the microwave method is fast and simple under microwave conditions. The microwave to point characteristics of carbon can ensure that the reaction is completed within 2 minutes. The high temperature generated by the rapid reaction can ensure the overall reduction of the metal precursor, the metal particle diameter is about 3-3.5 nm, and the metal particles are closely attached to the carbon powder, thereby improving the stability of the catalyst. Meanwhile, the application is simple to produce, does not need pH regulation, stabilizer addition and subsequent treatment, and is easy to mass produce.

[0008] Specifically, the evaluation method is as follows:

[0009] A preparation method of a core-shell structure Ru@Pt / C alkaline HER catalyst, comprising:

[0010] Step S1, uniformly mix and grind the carbon carrier and the ruthenium salt to obtain a first mixture;

[0011] Step S2, place the first mixture in a container and microwave heat for a period of time to obtain a black powder;

[0012] Step S3, add the platinum salt and the reducing agent to the black powder and uniformly mix and grind to obtain a second mixture;

[0013] Step S4, place the second mixture in a container, add water, and then microwave heat for a period of time; centrifuge, wash and dry the obtained product to obtain the catalyst.

[0014] Further, in step S1, the carbon carrier is selected from at least one of carbon black, mesoporous carbon, single-walled carbon nanotubes, multi-walled carbon nanotubes and carbon fibers.

[0015] Further, in step S1, the ruthenium salt is selected from at least one of ruthenium acetate, ruthenium acetylacetonate, triruthenium dodecacarbonyl, dichlorobisphenyl ruthenium (II) dimer, ruthenium tetra(triphenylphosphine), chloro ruthenium hexacarbonyl, tris(triphenylphosphine) dichlororuthenate or ruthenium ethanedionate. Further, in step S2, the microwave heating power is 300-1200 W, and the heating time is 30 s-180 s.

[0016] Further, in step S3, the platinum salt is selected from at least one of platinum acetylacetonate, potassium chloroplatinite, platinum dichloride ethylenediamine, platinum dichloride, platinum tetrachloride, potassium chloroplatinate, chloroplatinic acid, ammonium chloroplatinate, trimethylplatinum iodide, sodium tetrachloroplatinate (II), sodium hexachloroplatinate, ammonium chloroplatinite.

[0017] Further, the reducing agent in step S3 is at least one of hypophosphorous acid, sodium hypophosphite, ascorbic acid, sodium sulfite, sodium thiosulfate, oxalic acid, potassium borohydride, and sodium borohydride.

[0018] Further, the microwave heating power in step S4 is 300-1200W, and the heating time is 30s-180s.

[0019] Further, the mass ratio of the carbon carrier to the ruthenium salt is 1:1-1:4, the mass ratio of the platinum salt to the ruthenium salt is 1:1-1:10, and the mass ratio of the reducing agent to the black powder is 1:1-1:5.

[0020] The application also provides a core-shell structure Ru@Pt / C nano electrocatalyst, which has small particle size, good dispersity, and good alkaline electrolytic water hydrogen evolution reaction catalytic performance. Experiments show that the overpotential of the core-shell structure Ru@Pt / C provided by the method is only 17mV at 10mA cm -2 when 1mol KOH is used as an electrolyte, which is significantly lower than that of a commercial platinum carbon (Pt / C) catalyst (37mV).

[0021] The technical scheme provided by the application has at least the following beneficial effects: the raw materials for preparing the electrocatalyst are abundant in resources and low in cost, and the trace Pt doping also effectively reduces the cost of the traditional Pt / C catalyst. When applied in an alkaline electrolytic cell, the performance is better than that of an electrolytic cell composed of a commercial Pt / C catalyst material, and the electrocatalyst has excellent electrocatalytic performance and stability, and has a good development prospect. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical scheme in the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative effort.

[0023] Figure 1 is the XRD graph of the core-shell structure Ru@Pt / C prepared in Example 1 of the application.

[0024] Figure 2 is the TEM electron microscope graph of the core-shell structure Ru@Pt / C prepared in Example 1 of the application.

[0025] Figure 3 is the HRTEM graph of the core-shell structure Ru@Pt / C prepared in Example 1 of the application.

[0026] Figure 4 is the face scanning graph of the core-shell structure Ru@Pt / C prepared in Example 1 of the application.

[0027] Figure 5 This is a line scan image of the core-shell structure Ru@Pt / C prepared in Example 1 of the present invention.

[0028] Figure 6 This is a performance diagram of the core-shell structure Ru@Pt / C prepared in Example 1 of the present invention undergoing hydrogen evolution reaction in 1M KOH electrolyte. DETAILED DESCRIPTION

[0029] The technical solution of the present invention is described below.

[0030] In the embodiments of the present invention, words such as "exemplarily" and "for example" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as an "exemplary" in the present invention should not be interpreted as being preferred or advantageous over other embodiments or designs. Rather, the use of the word "exemplary" is intended to present concepts in a concrete manner. Furthermore, in the embodiments of the present invention, "and / or" can mean both or either of the two.

[0031] In the embodiments of the present invention, "image" and "picture" may sometimes be used interchangeably. It should be noted that, when the distinction between them is not emphasized, the meanings they convey are the same. "of," "corresponding," and "corresponding" may sometimes be used interchangeably. It should be noted that, when the distinction between them is not emphasized, the meanings they convey are the same.

[0032] In the embodiments of the present invention, sometimes a subscript such as W1 may be mistakenly written as a non-subscript form such as W1. When the difference is not emphasized, the meanings to be expressed are the same.

[0033] In order to make the technical problems, technical solutions and advantages to be solved by the present invention clearer, a detailed description will be given below with reference to specific embodiments.

[0034] Example 1

[0035] (1) Weigh 5 mg of MWCNT and 5 mg of Ru(acac)3, mix them, and grind them in a mortar for 10 minutes to mix them evenly.

[0036] (2) Place the mixture in a 5 mL quartz glass vial. In a household microwave oven, heat the mixture at 700 W for 1 minute. Allow the vial to cool naturally to room temperature.

[0037] (3) Add 2 mg of K₂PtCl₄ and 5 mg of NaH₂PO₂ to the black powder after the reaction. Mix thoroughly in a mortar and pestle. Place the mixture in a 5 mL quartz glass vial and add 20 μL of ultrapure water. Incubate the mixture in a household microwave oven at 700 W for 1 minute. Allow the vial to cool naturally to room temperature.

[0038] (4) Collect the black powder and centrifuge, sequentially use ultrapure water / absolute ethanol / ultrapure water to centrifugal clean, collect the powder and put into 120℃ vacuum drying treatment for 6h, cool to room temperature, collect the powder and carry out vacuum protection packaging.

[0039] The core-shell structured Ru@Pt / C electrocatalytic material prepared in Example 1 is subjected to electrocatalytic performance testing according to the following method:

[0040] (1) Electrochemical performance testing is carried out in an alkaline medium (1M KOH) using a three-electrode system, and the working electrode used in the HER test is the Ru@Pt / C electrocatalyst material, the reference electrode is a mercury oxide electrode, and the counter electrode is a platinum wire.

[0041] (2) The three-electrode device is used to test the HER performance of the catalyst material using the Chenhua CHI 760E electrochemical workstation. First, open circuit potential (OCPT) electrochemical activation testing is carried out until the voltage of the electrocatalytic material is stable or only has a slight fluctuation. Then, the scan rate is set to 5mV S -1 , the compensation value iR is set to 95%, and the HER linear sweep voltammetry test (LSV) is carried out in the voltage range of -0.8V-1.8V, respectively.

[0042] Example 2

[0043] (1) 5mg of SWCNTs and 10mg of Ru(acac)3 are weighed and mixed in a mortar for 10 minutes to uniformly mix.

[0044] (2) The mixture is placed in a 5mL quartz glass bottle. In a household microwave oven, react for 1 minute at a power of 700W, and wait for the quartz vial to cool to room temperature naturally.

[0045] (3) 5mg of K2PtCl4 and 10mg of NaH2PO2 are added to the black powder after the reaction, mixed uniformly in a mortar, and then placed in a 5mL quartz glass bottle and 20μL of ultrapure water is added. In a household microwave oven, react for 1 minute at a power of 700W, and wait for the quartz vial to cool to room temperature naturally.

[0046] (4) Collect the black powder and centrifuge, sequentially use ultrapure water / absolute ethanol / ultrapure water to centrifugal clean, collect the powder and put into 120℃ vacuum drying treatment for 6h, cool to room temperature, collect the powder and carry out vacuum protection packaging.

[0047] Example 3

[0048] (1) 5mg of Vulcan XC-72 carbon black and 10mg of Ru(acac)3 are weighed and mixed in a mortar for 30 minutes to uniformly mix.

[0049] (2) The mixture was put into a 10 mL quartz glass bottle. In a household microwave oven, the reaction was carried out for 1 minute at a power of 700 W, and the quartz vial was naturally cooled to room temperature.

[0050] (3) 5 mg of Pt(acac)2 and 10 mg of NaH2PO2 were added to the black powder after the reaction, and the mixture was uniformly mixed in a mortar and then put into a 20 mL quartz glass bottle and 30 μL of ultrapure water was added. In a household microwave oven, the reaction was carried out for 1 minute at a power of 700 W, and the quartz vial was naturally cooled to room temperature.

[0051] (4) The black powder was collected and centrifuged, and sequentially washed with ultrapure water / absolute ethanol / ultrapure water, and the powder was collected and vacuum-dried at 120°C for 6 h, cooled to room temperature, and the powder was collected and vacuum-protected packaged.

[0052] Example 4

[0053] (1) 5 mg of MWCNT and 5 mg of RuCl3 were weighed and mixed, and ground in a mortar for 10 minutes to uniformly mix.

[0054] (2) The mixture was put into a 5 mL quartz glass bottle. In a household microwave oven, the reaction was carried out for 1 minute at a power of 700 W, and the quartz vial was naturally cooled to room temperature.

[0055] (3) 2 mg of K2PtCl4 and 5 mg of C6H8O6 were added to the black powder after the reaction, and the mixture was uniformly mixed in a mortar and then put into a 5 mL quartz glass bottle and 20 μL of ultrapure water was added. In a household microwave oven, the reaction was carried out for 1 minute at a power of 700 W, and the quartz vial was naturally cooled to room temperature.

[0056] (4) The black powder was collected and centrifuged, and sequentially washed with ultrapure water / absolute ethanol / ultrapure water, and the powder was collected and vacuum-dried at 120°C for 6 h, cooled to room temperature, and the powder was collected and vacuum-protected packaged.

[0057] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for preparing a core-shell structure Ru@Pt / C catalyst, characterized in that: include: Step S1, mixing and grinding the carbon support and the ruthenium salt to obtain a first mixture; Step S2, placing the first mixture in a container and heating it with a microwave for a period of time to obtain a black powder; Step S3, adding platinum salt and reducing agent to the black powder and grinding and mixing to obtain a second mixture; Step S4: placing the second mixture in a container, adding water, and then heating it with a microwave for a period of time; centrifuging, washing, and drying the obtained product to obtain a catalyst.

2. The method according to claim 1, characterized in that In step S1, the carbon support is selected from at least one of carbon black, mesoporous carbon, single-walled carbon nanotubes, multi-walled carbon nanotubes, and carbon fibers.

3. The method according to claim 1, characterized in that In step S1, the ruthenium salt is selected from at least one of ruthenium acetate, ruthenium acetylacetonate, triruthenium dodecacarbonyl, dichlorophenylruthenium dimer, tetrakistriphenylphosphine ruthenium, hexacarbonyl ruthenium chloride, tris(triphenylphosphine)dichlororuthenium or ethylenedicarbonylruthenium.

4. The method according to claim 1, wherein In step S2, the microwave heating power is 700W and the heating time is 30s-180s.

5. The method according to claim 1, wherein In step S3, the platinum salt is selected from at least one of platinum acetylacetonate, potassium chloroplatinite, ethylenediamineplatinic chloride, platinum dichloride, platinum tetrachloride, potassium chloroplatinate, chloroplatinic acid, ammonium chloroplatinate, trimethylplatinum iodide, sodium tetrachloroplatinate (II), sodium hexachloroplatinate, and ammonium chloroplatinate.

6. The method according to claim 1, characterized in that In step S3, the reducing agent is selected from at least one of hypophosphorous acid, sodium hypophosphite, ascorbic acid, sodium sulfite, sodium thiosulfate, oxalic acid, potassium borohydride, and sodium borohydride.

7. The method according to claim 1, characterized in that In step S4, the microwave heating power is 700W and the heating time is 30s-180s.

8. The method according to claim 1, characterized in that The mass ratio of the carbon carrier to the ruthenium salt is 1:1-1:4; the mass ratio of the platinum salt to the ruthenium salt is 1:1-1:10; and the mass ratio of the reducing agent to the black powder is 1:1-1:

5. 9 . A core-shell structured Ru@Pt / C catalyst prepared according to the method according to claim 1 , having an overpotential of 17 mV.

10. Use of the catalyst according to claim 9 in hydrogen evolution reaction by water electrolysis.

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