Barium-based B-site high-entropy perovskite oxide and preparation method thereof

Abstract

The invention discloses a barium-based B-site high-entropy perovskite type oxide and a preparation method thereof, the molecular formula of the barium-based B-site high-entropy perovskite type oxide is represented as ABO3, the A site is Ba element, the B site is at least five of Ti, Cr, Mn, Fe, Co, Ni, Cu, Y and Zr element, the molar content of the A-site element is 50%, and the molar content range of the B-site element is 5%-20%; by optimizing the configuration entropy, the novel barium-based B-site high-entropy perovskite OER catalyst is prepared, and the OER activity and stability of perovskite are greatly improved. In devices such as an alkaline electrolytic bath and an anion exchange membrane electrolytic bath, the catalyst with high OER activity can effectively reduce the overpotential of electrolyzed water, and the oxygen production and hydrogen production cost of the electrolytic bath is greatly reduced.

Description

Technical Field

[0001] The invention relates to the technical field of catalysts for oxygen evolution reaction by electrolysis of water, and in particular to a barium-based B-site high-entropy perovskite-type oxide and a preparation method thereof. Background Art

[0002] In recent years, the world's energy has undergone major changes, and hydrogen has been hailed as a "clean energy". Therefore, the research on large-scale water electrolysis hydrogen production methods has been included in the national energy development plan, and a large amount of research has been carried out around water electrolysis hydrogen production equipment.

[0003] The development of efficient and stable cathode hydrogen evolution reaction (HER) and anodic oxygen evolution reaction (OER) electrocatalysts is crucial to the application of water splitting electrolyzers. Among them, since OER has particularly slow reaction kinetics, it is necessary to develop high-performance electrocatalysts to reduce the reaction overpotential in practical applications.

[0004] Oxides of noble metals Ru or Ir are currently commonly used OER catalysts, but in the OER reaction, due to the dispersion and oxidation of noble metal atoms during the OER reaction, the noble metal atoms face the problem of dissolution. The reserves and cost of Ru and Ir also limit the application of noble metal catalysts. To this end, the present invention proposes a barium-based B-site high-entropy perovskite oxide and a preparation method thereof that can solve the above problems. Summary of the invention

[0005] The object of the present invention is to provide a barium-based B-site high entropy perovskite-type oxide and a preparation method thereof, so as to solve the problems raised in the above-mentioned background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A barium-based B-site high entropy perovskite-type oxide, wherein the barium-based B-site high entropy perovskite-type oxide molecular formula is ABO3, wherein the A-site is Ba element, and the B-site is at least five of the elements Ti, Cr, Mn, Fe, Co, Ni, Cu, Y, and Zr;

[0008] The molar content of the A-position element is 50%, and the molar content of the B-position element is in the range of 5%-20%.

[0009] A method for preparing a barium-based B-site high entropy perovskite-type oxide comprises the following steps:

[0010] S1, dissolving a metal nitrate containing an A-site element and a B-site element and glycine in an appropriate amount of distilled water to obtain a mixed solution, wherein the molar ratio of the metal nitrate to glycine is 1:(1-10);

[0011] S2, magnetically stirring the mixed solution obtained in S1 in a water bath at 50-80° C. until a sol is formed;

[0012] S3, heating the sol obtained in step S2 on a hot plate at 200-350° C. until a self-combustion reaction occurs to obtain a high-entropy perovskite oxide precursor powder;

[0013] S4. The high entropy perovskite oxide precursor powder obtained in S3 is calcined in a muffle furnace at 850-1400° C. for 3-10 h to obtain a Ba-based B-site high entropy perovskite oxide.

[0014] As a preferred technical solution, in step S1, the metal nitrate containing the A-site element is barium nitrate; the metal salt containing the B-site element is at least five of tetrabutyl titanate, chromium nitrate, manganese nitrate, iron nitrate, cobalt nitrate, nickel nitrate, copper nitrate, yttrium nitrate and zirconium nitrate.

[0015] As a preferred technical solution, in step S2, the temperature of the water bath is 65-75°C.

[0016] As a preferred technical solution, in step S3, the temperature of the hot plate is at most 250-300°C.

[0017] As a preferred technical solution, in step S4, the heating rate of the muffle furnace is 3-5°C / min, and the cooling rate is 3-5°C / min.

[0018] A barium-based B-site high-entropy perovskite-type oxide, which is used as a catalyst for oxygen evolution reaction in alkaline water electrolysis.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] By optimizing the configurational entropy, a new type of barium-based B-site high-entropy perovskite OER catalyst was prepared, which greatly improved the OER activity and stability of the perovskite. In devices such as alkaline electrolyzers and anion exchange membrane electrolyzers, catalysts with high OER activity can effectively reduce the overpotential of water electrolysis and greatly reduce the oxygen and hydrogen production costs of the electrolyzer. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is the X-ray diffraction pattern of the high entropy perovskite oxide obtained in Example 1;

[0022] Figure 2 This is the polarization curve of the high entropy perovskite oxide obtained in Example 1 in 1M KOH solution;

[0023] Figure 3 The electrochemical impedance spectroscopy diagram of the high entropy perovskite oxide obtained in Example 1 at an overpotential of 300 mV;

[0024] Figure 4 The high entropy perovskite oxide obtained in Example 1 is 200 mA cm -2 Stability under current density;

[0025] Figure 5 The polarization curve of the alkaline electrolytic cell assembled with the high entropy perovskite oxide obtained in Example 1 and a commercial platinum-nickel cathode measured in 1M KOH solution;

[0026] Figure 6 The alkaline electrolytic cell assembled with the high entropy perovskite oxide obtained in Example 1 and a commercial platinum-nickel cathode was used at 1 Acm -2 Stability measured at current density. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] Embodiment 1

[0029] The material composition is Ba(CoFeYNiCu)O 3-δ 5 mmol of barium nitrate, 1 mmol of cobalt nitrate, 1 mmol of iron nitrate, 1 mmol of yttrium nitrate, 1 mmol of nickel nitrate and 1 mmol of copper nitrate were weighed, and then 3.5 times the molar mass of the metal nitrates and glycine were dissolved in an appropriate amount of distilled water to obtain a mixed solution.

[0030] The mixture was stirred magnetically in a water bath at 60°C until a sol was formed.

[0031] The obtained sol was heated on a hot plate at 250°C until a self-combustion reaction occurred to obtain a high-entropy perovskite oxide precursor powder.

[0032] The obtained high entropy perovskite oxide precursor powder was calcined in a muffle furnace at 1050 °C for 3 h to obtain Ba(CoFeYNiCu)O 3-δ High entropy perovskite oxides.

[0033] See also Figure 1 , the obtained high entropy perovskite oxide is measured by X-ray diffraction to obtain a spectrum;

[0034] See also Figure 2 , the polarization curve of the obtained high entropy perovskite oxide was measured in 1M KOH solution;

[0035] See also Figure 3 , the electrochemical impedance spectroscopy of the obtained high entropy perovskite oxide was measured at an overpotential of 300 mV;

[0036] See also Figure 4 The obtained high entropy perovskite oxide was subjected to 200 mA cm -2 The stability diagram was measured under current density;

[0037] See also Figure 5 The polarization curve of the alkaline electrolytic cell assembled with the obtained high-entropy perovskite oxide and a commercial platinum-nickel cathode was measured in a 1 M KOH solution.

[0038] See also Figure 6 The obtained high entropy perovskite oxide was assembled with a commercial platinum-nickel cathode into an alkaline electrolyzer at 1 A cm -2 Stability diagram measured at current density.

[0039] Embodiment 2

[0040] The material composition is Ba(CoFeYNi2Cu)O 3-δ , weigh 6 mmol of barium nitrate, 1 mmol of cobalt nitrate, 1 mmol of iron nitrate, 1 mmol of yttrium nitrate, 2 mmol of nickel nitrate and 1 mmol of copper nitrate according to a stoichiometric ratio, and then dissolve glycine and metal nitrate with a molar mass of 3.5 times that of the metal nitrate in an appropriate amount of distilled water to obtain a mixed solution.

[0041] The mixture was stirred magnetically in a water bath at 60°C until a sol was formed.

[0042] The obtained sol was heated on a hot plate at 250°C until a self-combustion reaction occurred to obtain a high-entropy perovskite oxide precursor powder.

[0043] The obtained high entropy perovskite oxide precursor powder was calcined in a muffle furnace at 1050 °C for 3 h to obtain Ba(CoFeYNi2Cu)O 3-δ High entropy perovskite oxides.

[0044] Embodiment 3

[0045] The material composition is Ba(CoFeNiTiMn)O 3-δ , 5 mmol of barium nitrate, 1 mmol of cobalt nitrate, 1 mmol of iron nitrate, 1 mmol of nickel nitrate, 1 mmol of tetrabutyl titanate and 1 mmol of manganese nitrate were weighed according to the stoichiometric ratio, and then glycine and metal nitrate with a molar mass of 5 times that of the metal nitrate were dissolved in an appropriate amount of distilled water to obtain a mixed solution.

[0046] The mixture was stirred magnetically in a water bath at 60°C until a sol was formed.

[0047] The obtained sol was heated on a hot plate at 250°C until a self-combustion reaction occurred to obtain a high-entropy perovskite oxide precursor powder.

[0048] The obtained high entropy perovskite oxide precursor powder was calcined in a muffle furnace at 1200 °C for 5 h to obtain Ba(CoFeNiTiMn)O 3-δ High entropy perovskite oxides.

[0049] Embodiment 4

[0050] The material composition is Ba(CoFeNiZrCr)O 3-δ , weigh 5 mmol of barium nitrate, 1 mmol of cobalt nitrate, 1 mmol of iron nitrate, 1 mmol of nickel nitrate, 1 mmol of zirconium nitrate and 1 mmol of chromium nitrate according to the molar ratio, and then dissolve glycine and metal nitrate with a molar mass of 3.5 times of the metal nitrate in an appropriate amount of distilled water to obtain a mixed solution.

[0051] The mixture was stirred magnetically in a water bath at 60°C until a sol was formed.

[0052] The obtained sol was heated on a hot plate at 250°C until a self-combustion reaction occurred to obtain a high-entropy perovskite oxide precursor powder.

[0053] The obtained high entropy perovskite oxide precursor powder was calcined in a muffle furnace at 1150 °C for 5 h to obtain Ba(CoFeNiZrCr)O 3-δ High entropy perovskite oxides.

[0054] Embodiment 5

[0055] The material composition is Ba(CoFeNiZrCrY)O 3-δ , weigh 6 mmol of barium nitrate, 1 mmol of cobalt nitrate, 1 mmol of iron nitrate, 1 mmol of nickel nitrate, 1 mmol of zirconium nitrate, 1 mmol of chromium nitrate and 1 mmol of yttrium nitrate according to the molar ratio, and then dissolve glycine and metal nitrate with a molar mass of 3.5 times of the metal nitrate in an appropriate amount of distilled water to obtain a mixed solution.

[0056] The mixture was stirred magnetically in a water bath at 60°C until a sol was formed.

[0057] The obtained sol was heated on a hot plate at 250°C until a self-combustion reaction occurred to obtain a high-entropy perovskite oxide precursor powder.

[0058] The obtained high entropy perovskite oxide precursor powder was calcined in a muffle furnace at 1400 °C for 5 h to obtain Ba(CoFeNiZrCrY)O 3-δ High entropy perovskite oxides.

[0059] Table 1 compares the performance of the alkaline electrolytic cell composed of the catalysts obtained in Examples 1 to 5 and a commercial platinum-nickel cathode:

[0060] Electrocatalyst <![CDATA[Voltage (@ 2 A / cm -2 )]]> Embodiment 1 2V Embodiment 2 1.8V Embodiment 3 2.1V Embodiment 4 2.2V Embodiment 5 2.5V

[0061] Table 1

[0062] In summary, a new type of barium-based B-site high-entropy perovskite OER catalyst was prepared by optimizing the configurational entropy, which greatly improved the OER activity and stability of the perovskite. In devices such as alkaline electrolyzers and anion exchange membrane electrolyzers, catalysts with high OER activity can effectively reduce the overpotential of water electrolysis and greatly reduce the oxygen and hydrogen production costs of the electrolyzer.

[0063] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A barium-based B-site high entropy perovskite-type oxide, characterized in that: The barium-based B-site high entropy perovskite-type oxide molecular formula is expressed as ABO3, where the A-site is Ba element and the B-site is at least five of the elements Ti, Cr, Mn, Fe, Co, Ni, Cu, Y, and Zr; The molar content of the A-position element is 50%, and the molar content of the B-position element is in the range of 5%-20%.

2. A method for preparing the barium-based B-site high entropy perovskite-type oxide according to claim 1, comprising the following steps: S1, dissolving a metal nitrate containing an A-site element and a B-site element and glycine in an appropriate amount of distilled water to obtain a mixed solution, wherein the molar ratio of the metal nitrate to glycine is 1:(1-10); S2, magnetically stirring the mixed solution obtained in S1 in a water bath at 50-80° C. until a sol is formed; S3, heating the sol obtained in step S2 on a hot plate at 200-350° C. until a self-combustion reaction occurs to obtain a high-entropy perovskite oxide precursor powder; S4. The high entropy perovskite oxide precursor powder obtained in S3 is calcined in a muffle furnace at 850-1400° C. for 3-10 h to obtain a Ba-based B-site high entropy perovskite oxide.

3. The method for preparing a barium-based B-site high entropy perovskite-type oxide according to claim 2, characterized in that: In step S1, the metal nitrate containing the A-site element is barium nitrate; the metal salt containing the B-site element is at least five of tetrabutyl titanate, chromium nitrate, manganese nitrate, iron nitrate, cobalt nitrate, nickel nitrate, copper nitrate, yttrium nitrate and zirconium nitrate.

4. The method for preparing a barium-based B-site high entropy perovskite-type oxide according to claim 2, characterized in that: In step S2, the temperature of the water bath is 65-75°C.

5. The method for preparing a barium-based B-site high entropy perovskite-type oxide according to claim 2, characterized in that: In step S3, the temperature of the hot plate is at most 250-300°C.

6. The method for preparing a barium-based B-site high entropy perovskite-type oxide according to claim 2, characterized in that: In step S4, the heating rate of the muffle furnace is 3-5°C / min, and the cooling rate is 3-5°C / min.

7. The barium-based B-site high entropy perovskite-type oxide according to claim 1 is used as a catalyst for oxygen evolution reaction in alkaline water electrolysis.

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