Lead-doped low-temperature synthesized yttrium ruthenate catalyst, preparation method and application thereof

Abstract

The present invention relates to a lead-doped low-temperature synthesized yttrium ruthenate catalyst, a preparation method and an application thereof. The molecular formula of the yttrium ruthenate catalyst is Y 2‑x Pb x Ru2O7, of which 0

Description

Technical Field

[0001] The present invention belongs to the field of energy materials, in particular to the technical field of electrochemical material preparation, and specifically relates to a lead-doped low-temperature synthesized yttrium ruthenate catalyst, a preparation method and an application thereof. Background Art

[0002] Clean energy consumption, such as wind, solar, and hydropower, is increasingly accounting for 41% of primary energy consumption by 2030, up from 25.3% in 2020, and further reaching 90% by 2060. my country's renewable energy-rich regions have a total instantaneous capacity of 187.3 GW, representing enormous potential. However, the supply of renewable energy is subject to significant volatility and uneven distribution, while the demand side is characterized by a large number of random users and a haphazard use of electricity. This leads to significant waste of clean energy, with the highest wind power curtailment rate reaching 39%. Therefore, effective energy storage technologies are urgently needed to address the temporal and regional mismatches caused by this random supply and demand. Hydrogen, a recognized clean secondary energy source, offers the advantages of zero emissions, high efficiency, high calorific value, and the ability to circulate between renewable energy supply and consumption through electrolysis cells. Therefore, the technology of converting intermittent electricity into hydrogen for energy storage through water electrolysis has gained momentum in recent years, with the development of water electrolysis technology being a key driver. The key step in the water electrolysis process, and the main source of overpotential for the reaction, is the oxygen evolution reaction (OER). Its slow kinetics result in additional energy consumption, necessitating the development of efficient OER catalysts. Currently, complex metal oxides with ruthenium-based pyrochlore structures are being widely studied as OER catalysts. Yttrium ruthenate, for example, has the advantages of low precious metal content and excellent stability in acidic media, making it a promising alternative to commercial IrO2 as an anode catalyst for proton exchange membrane water electrolysis devices. However, conventional preparation methods for such materials involve high-temperature preparation (1100°C) and require a holding time of 18 to 72 hours, which consumes significant energy. Therefore, reducing the preparation temperature and heat treatment time of ruthenium-based pyrochlore-structured materials is crucial for their widespread application. Summary of the Invention

[0003] To address the problem of high temperatures and long preparation times required for the existing preparation of pyrochlore-structured catalysts, the present invention provides a lead-doped, low-temperature synthesized yttrium ruthenate catalyst, its preparation method, and application. The catalyst is obtained by low-temperature heat treatment, significantly reducing the temperature at which the yttrium ruthenate pyrochlore structure is formed. The lead doping significantly promotes the formation of pyrochlore crystals, reduces the temperature and heat treatment time required for the formation of the structure, and the resulting catalyst is prepared at a low temperature and in a short time. The ruthenium, yttrium, and lead in the catalyst exist in a pyrochlore structure, exhibiting excellent oxygen evolution catalytic activity and stability in acidic media such as sulfuric acid, and can be widely used in electrolytic devices involving oxygen evolution reactions. The preparation method of the present invention has low energy consumption, a simple process, and is universally applicable to various types of pyrochlore materials, promising large-scale production.

[0004] The present invention adopts the following technical solution: a lead-doped low-temperature synthesized yttrium ruthenate catalyst, wherein the yttrium ruthenate catalyst exists in the form of pyrochlore structure particles, and its molecular formula is Y 2-x Pb x Ru2O7, of which 0 <x<2。

[0005] The present invention also protects a preparation method of lead-doped low-temperature synthesized yttrium ruthenate, which comprises dissolving metal salts of ruthenium, yttrium and lead as precursors in water, adding water-soluble organic matter as fuel, aging to form a gel, and then heat-treating at a relatively low temperature to obtain a lead-doped low-temperature synthesized yttrium ruthenate catalyst.

[0006] The present invention also protects a method for preparing the catalyst, which comprises dissolving ruthenium and yttrium metal salts as precursors in water, adding lead metal salts for doping, adding water-soluble organic matter as fuel, aging to form a gel, and then heat-treating to prepare a lead-doped low-temperature synthesized yttrium ruthenate catalyst.

[0007] Furthermore, the preparation method comprises the following steps:

[0008] (1) dissolving ruthenium salt, yttrium salt and lead salt in water, and then adding water-soluble organic matter and oxidizing acid to obtain a clear mixed solution;

[0009] (2) drying and aging the solution obtained in step (1) to obtain a dry gel intermediate material;

[0010] (3) The gel in step (2) is subjected to a one-step heat treatment at a relatively low temperature to obtain a lead-doped low-temperature synthesized yttrium ruthenate catalyst.

[0011] In a preferred embodiment of the present invention, the water-soluble organic matter is selected from one or more of ethylenediaminetetraacetic acid, citric acid, citric acid monohydrate, urea, and glycine.

[0012] In a preferred embodiment of the present invention, the molar ratio between the water-soluble organic matter and the total metal ions is 10:1 to 1:1.

[0013] In a preferred embodiment of the present invention, the ruthenium salt is selected from one or more of ruthenium nitrosyl nitrate, ruthenium trichloride, and ruthenium acetate.

[0014] In a preferred embodiment of the present invention, the yttrium salt is selected from one or more of yttrium bromide, yttrium nitrate, yttrium sulfate, yttrium chlorate, yttrium bromate, yttrium carbonate hydroxide, and yttrium oxalate.

[0015] In a preferred embodiment of the present invention, the lead salt is selected from one or more of nitrates, acetates, chlorides, and complex salts containing lead.

[0016] In a preferred embodiment of the present invention, the molar ratio of the ruthenium metal salt to the yttrium metal salt is 3:1 to 1:3.

[0017] In a preferred embodiment of the present invention, the molar ratio of the lead metal salt to the ruthenium metal salt is 1:100 to 1:1.

[0018] In a preferred embodiment of the present invention, the added oxidizing acid is one or more of nitric acid, perchloric acid, sulfuric acid, and hypochlorous acid.

[0019] In a preferred embodiment of the present invention, the ruthenium ion concentration in the mixed solution is (0.001-0.1) mol / L, the yttrium ion concentration is (0.001-0.1) mol / L, and the lead ion concentration is (0.001-0.1) mol / L. The concentration of oxidizing acid radicals to total metal ions in the solution is in a ratio of 3:1 to 1:3.

[0020] In a preferred embodiment of the present invention, the calcination temperature of the one-step heat treatment is 200 to 950° C., and the holding time is 2 to 12 hours.

[0021] The present invention also protects the use of the lead-doped low-temperature synthesized yttrium ruthenate catalyst in the electrocatalytic oxygen evolution reaction in acidic media such as sulfuric acid.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] (1) The preparation of pyrochlore structure does not require high temperature (above 1100°C) heat treatment and long-term (18 to 72) hours of heat preservation process. A good pyrochlore structure can be formed at a lower temperature and in a shorter time.

[0024] (2) It is universally applicable to reducing the pyrochlore structure formation temperature of various pyrochlore structure materials including yttrium ruthenate.

[0025] (3) The prepared lead-doped low-temperature synthesized yttrium ruthenate catalyst has excellent oxygen evolution catalytic performance and good stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention will be further described below with reference to the accompanying drawings:

[0027] Figure 1 This is a SEM image of the catalyst obtained in Example 1.

[0028] Figure 2 is the XRD pattern of the catalyst obtained in Example 1.

[0029] Figure 3 This is the polarization curve of the catalyst obtained in Example 1 in 0.5 M sulfuric acid solution.

[0030] Figure 4 This is a SEM image of the catalyst obtained in Example 2.

[0031] Figure 5 This is the polarization curve of the catalyst obtained in Example 3 in 0.5 M sulfuric acid solution.

[0032] Figure 6 is the XRD pattern of the catalyst obtained in Example 4.

[0033] Figure 7 This is the polarization curve of the catalyst obtained in Example 5 in 0.5 M sulfuric acid solution.

[0034] Figure 8 This is a chronopotentiometry curve of the catalyst obtained in Example 5 in 0.5 M sulfuric acid solution. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solutions and beneficial effects of the present invention more clear, the present invention is described with the following specific embodiments, but the present invention is by no means limited to these examples.

[0036] Example 1

[0037] The preparation of lead-doped low-temperature synthesized yttrium ruthenate catalytic material is carried out as follows:

[0038] (1) Dissolve 0.84 g of citric acid in 10 mL of deionized water, add 0.144 g of yttrium nitrate, 0.104 g of ruthenium nitrate, 0.037 g of lead oxalate, and 85 μL of perchloric acid solution, and dissolve evenly under ultrasonication.

[0039] (2) heating and drying the above solution in an oven at 80°C for aging to obtain a fluffy dry gel;

[0040] (3) The gel was placed in a muffle furnace at 400°C and heated for 8 hours to allow the gel to burn completely. After complete combustion, the catalyst powder product Y was obtained. 1.5 Pb 0.5 Ru2O7.

[0041] The SEM image of lead-doped low-temperature synthesized yttrium ruthenate is shown in Figure 1 It can be seen that the size of the catalyst nanoparticles is 20 to 80 nm. Figure 2 , indicating that a good pyrochlore structure can be formed at low temperature. The catalyst has excellent oxygen evolution catalytic activity. Compared with the commercial IrO2 catalyst, the electrochemical test in the acidic medium of 0.5M H2SO4 was carried out at 10mA cm -2 The current density has a lower overpotential, see Figure 3 .

[0042] Example 2

[0043] The preparation process of Example 1 was adopted, except that the precursor salt was replaced with 0.173g yttrium nitrate, 0.104g ruthenium nitrate, and 0.015g lead oxalate. The morphology was basically maintained, and the SEM showed Figure 4 , indicating that changing the proportion of added metal elements will change the size of the yttrium ruthenate catalyst particles.

[0044] Example 3

[0045] The preparation process of Example 1 was adopted, except that 0.144g of yttrium nitrate was replaced with 0.163g of praseodymium nitrate to obtain a lead-doped low-temperature synthesized praseodymium ruthenate catalytic material. It also showed oxygen evolution catalytic activity comparable to that of commercial IrO2 catalysts, as shown in Figure 1. Figure 5 This shows that this method is universally applicable to the preparation of different pyrochlore-structured materials.

[0046] Example 4

[0047] The preparation process of Example 1 was adopted, except that 0.84 g of citric acid was replaced with 0.26 g of urea. Its XRD showed that the change of organic matter also formed a pyrochlore structure, as shown in FIG. Figure 6 .

[0048] Example 5

[0049] The preparation process of Example 1 is adopted, except that the heat treatment temperature is changed to 700°C. At this temperature, a lead-doped yttrium ruthenate catalyst with good oxygen evolution catalytic activity can also be obtained. Figure 7 In the acidic medium of 0.5M H2SO4, the -2 The stability test under constant current density shows that the activity does not decrease after a long reaction time. Figure 8 .

[0050] The above embodiments show and describe the main features and main advantages of the present invention in detail, but the present invention is not limited to the embodiments. Those skilled in the art can make various equivalent modifications or substitutions without violating the spirit of the present invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A preparation method of a lead-doped yttrium ruthenate catalyst synthesized at low temperature, wherein the yttrium ruthenate catalyst exists in the form of pyrochlore-structured particles with the molecular formula Y 2-x Pb x Ru2O7, where 0 < x < 2, and is characterized in that The steps include: (1) dissolving ruthenium salt, yttrium salt and lead salt in water, and then adding water-soluble organic matter and oxidizing acid to obtain a clear mixed solution; (2) drying and aging the solution obtained in step (1) to obtain a dry gel intermediate material; (3) subjecting the gel in step (2) to a one-step heat treatment at a relatively low temperature to obtain a lead-doped low-temperature synthesized yttrium ruthenate catalyst; The molar ratio of the ruthenium salt to the yttrium salt is 3:1 to 1:3; the molar ratio of the lead salt to the ruthenium salt is 1:100 to 1:1; the water-soluble organic matter is selected from one or more of ethylenediaminetetraacetic acid, citric acid, citric acid monohydrate, urea, and glycine; the added oxidizing acid is one or more of nitric acid, perchloric acid, sulfuric acid, and hypochlorous acid; The calcination temperature of the one-step heat treatment is 200-400° C., and the holding time is 2-12 hours.

2. The preparation method according to claim 1, characterized in that The molar ratio between water-soluble organic matter and total metal ions is 10:1 to 1:

1.

3. The preparation method according to claim 1, characterized in that The ruthenium salt is selected from one or more of ruthenium nitrosyl nitrate, ruthenium trichloride, and ruthenium acetate; the yttrium salt is selected from one or more of yttrium bromide, yttrium nitrate, yttrium sulfate, yttrium chlorate, yttrium bromate, yttrium hydroxide carbonate, and yttrium oxalate; and the lead salt is one or more of nitrate, acetate, chloride, and complex salt containing the lead element.

4. The preparation method according to claim 1, characterized in that The ruthenium ion concentration in the mixed solution is (0.001-0.1) mol / L, the yttrium ion concentration is (0.001-0.1) mol / L, the lead ion concentration is (0.001-0.1) mol / L, and the oxidizing acid radical concentration to the total metal ion concentration in the solution is 3:1-1:

3.

5. The yttrium ruthenate catalyst prepared by the preparation method according to any one of claims 1 to 4.

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