Self-assembled carbonate alloy-perovskite electrode material and preparation method thereof

Abstract

The invention discloses a self-assembled carbonate amp; the invention discloses an alloy-perovskite electrode material and a preparation method thereof, and relates to the technical field of electrode catalyst materials of solid oxide batteries, and the preparation method comprises the following steps: preparing Sr2AxFe < 1.5 > Mo < 0.3 > B < y > O < 6-delta > primary powder by adopting a self-combustion method, and carrying out high-temperature calcination to prepare Sr2AxFe < 1.5 > Mo < 0.3 > B < y > O < 6-delta > final powder; the final powder is subjected to solution treatment and high-temperature reduction treatment, carbonate and alloy nanoparticles are self-assembled and modified on the surface of the Sr2AxFe < 1.5 > Mo < 0.3 > B < y > O < 6-delta > perovskite electrode, and the Sr2AxFe < 1.5 > Mo < 0.3 > B < y > O < 6-delta > electrode material is obtained. The electrode material has relatively high activity on conversion adsorption, dissociation and catalytic reaction of hydrocarbon fuel and carbon dioxide, and meanwhile, the perovskite skeleton has relatively high oxygen transmission activity; the fuel electrode catalyst is subjected to a combined solution reaction and a high-temperature reaction, an in-situ reaction is carried out on a surface structure in a molecular scale, meanwhile, a stable nano-composite system is self-assembled, the structure is beneficial to surface gas adsorption and dissociation, meanwhile, carbonate provides an anti-carbon deposition stabilizing effect and carbon and oxygen species transfer activity, and the carbon and oxygen transfer activity is improved. The alloy provides electron transfer and catalysis.

Description

Technical Field

[0001] The present invention relates to the technical field of electrode catalyst materials for solid oxide batteries, and in particular to a self-assembled carbonate & alloy-perovskite electrode material and a preparation method thereof. Background Art

[0002] At present, solid oxide cell (SOC) is an important technology for realizing efficient energy conversion and storage, which is realized by the discharge process of solid oxide fuel cell (SOFC) and the charging process of solid oxide electrolysis cell (SOEC). Compared with low-temperature (<120℃) proton exchange membrane fuel cells and electrolyzers that mainly use hydrogen and water conversion systems, solid oxide cells can use more widely available hydrocarbon fuels and carbon dioxide and water for conversion, thereby realizing efficient utilization of hydrocarbon fuels and capture, storage and utilization of carbon dioxide. It uses high temperature (650-850℃) operation, and the conversion efficiency, reaction rate and mass transfer rate are all higher than those of low-temperature fuel cells and electrolyzers; the required energy is composed of electrical energy and thermal energy. Using industrial waste heat to increase the temperature of the electrolyzer can increase the proportion of thermal energy (28%-34%), and the consumption of electrical energy will be reduced (72%-66%). Therefore, SOC has the advantage of high efficiency and energy saving. In theory, it can achieve large-scale, low-pollution, efficient and controllable energy conversion and storage through hydrocarbon fuels and electrolysis of carbon dioxide and water to facilitate transportation, thus promoting a win-win situation of energy conservation, emission reduction and economic energy storage.

[0003] Compared with the oxygen reaction process on the SOC oxygen electrode, the energy barrier of the fuel electrode electrocatalytic hydrogen-oxygen fuel oxidation and electrolytic carbon dioxide reduction reaction is higher, and the polarization loss is larger, which is the main factor restricting the SOC performance. At present, considering the economic and electrocatalytic activity, metal-based composite ceramics, such as commercial Ni-based Zr 0.8 Y 0.2 O 1.9 (YSZ), with high activity, is often used as a fuel electrode for SOFC and SOEC. However, since Ni in the composite obtained by the traditional method is prone to agglomeration and carbon deposition, the catalytic activity and long-term stability of batteries and electrolytic cells are still problematic, which restricts its large-scale application. To solve the stability problem, perovskite materials have been widely developed and studied due to the presence of a large number of oxygen active species inside, high resistance to carbon deposition and stability, but their catalytic activity is lower than that of Ni-based catalyst materials, which restricts their application at medium and low temperatures.

[0004] Therefore, it is urgent to study a SOC electrode material that balances activity and stability. Summary of the invention

[0005] In order to solve the above technical problems, the present invention discloses a self-assembled carbonate & alloy-perovskite electrode material and a preparation method thereof. The method comprehensively considers the activity advantages of traditional metal-based electrode catalysts in electrocatalytic oxidation or reduction reactions in carbon-containing atmospheres, and the advantages of perovskite catalysts in anti-carbon deposition and long-term stability. The perovskite oxide designed and prepared by doping excessive alkaline metal ions at the A position and regulating the composition and proportion of transition metal ions at the B position can self-assemble in situ to form a carbonate and alloy complex in an acidic solution and a high-temperature reducing atmosphere, and forms composite nanoparticles of nano-active metal catalytic phase and alkaline metal oxide on the surface, which have high electrocatalytic activity and structural stability, and the skeleton is a perovskite oxide with high oxygen accommodating capacity, thereby improving the anti-carbon deposition stability.

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

[0007] A method for preparing a self-assembled carbonate & alloy-perovskite electrode material comprises the following steps:

[0008] Preparation of Sr2A by self-combustion method x Fe 1.5 Mo 0.3 B y O 6-δ The initial powder is calcined at 850-1250℃ for 1-10h to obtain Sr2A x Fe 1.5 Mo 0.3 B y O 6-δ Final powder;

[0009] Sr2A x Fe 1.5 Mo 0.3 B y O 6-δ The final powder was treated with solution and high temperature reduction. x Fe 1.5 Mo 0.3 B y O 6-δ The perovskite electrode surface is self-assembled and modified with carbonate and alloy nanoparticles to obtain Sr2A nanostructured in situ on the micro-skeleton surface. x Fe 1.5 Mo 0.3 B y O 6-δ Electrode material.

[0010] Optionally, x=0.01-0.20, y=0.20-0.35; position A is one of potassium, sodium, magnesium and calcium; position B is one or two of nickel, copper, iron, zinc and cobalt.

[0011] Optionally, the solution treatment process is to convert Sr2A x Fe 1.5 Mo 0.3 B y O 6-δ The final powder is placed in a specific solution and allowed to stand for 2 to 18 hours, filtered and dried, and then calcined at 500 to 800° C. for 2 hours, and the above-mentioned standing and calcining processes are repeated 1 to 3 times; wherein the specific solution is a carbon dioxide solution, or an acetic acid solution, or a mixed solution of ethanol and water, and the volume fraction of ethanol is 0 to 90 vol%.

[0012] Optionally, the high-temperature reduction process is to place the final powder after solution treatment in a mixed gas for 2 to 12 hours, wherein the mixed gas is a mixture of carbon monoxide, carbon dioxide and nitrogen, wherein the volume fraction of carbon monoxide is 10 to 50 vol%, the volume fraction of carbon dioxide is 5 to 20 vol%, and the volume fraction of nitrogen is 20 to 85 vol%; the flow rate is 10 to 80 mL / min; finally, calcination is performed at 650 to 800°C for 0.5 to 4 hours.

[0013] The present invention also provides a self-assembled carbonate & alloy-perovskite electrode material prepared by the above method.

[0014] The beneficial effects of the present invention are:

[0015] (1) The present invention uses weakly acidic solution conditions to react the A-site alkaline metal oxide that is excessively precipitated from the perovskite in situ, and after high-temperature calcination in an air atmosphere, a large number of nanocarbonate species can be formed on the surface, thereby enhancing the adsorption and dissociation activity of the electrode surface during electrocatalytic oxidation of hydrocarbon fuels and reduction of carbon dioxide, the transmission activity of carbon-oxygen intermediate species, and the anti-carbon deposition property. At the same time, the micron skeleton is a perovskite oxide with a high oxygen holding capacity, which is also conducive to improving the surface carbon removal reaction activity and enhancing the anti-carbon deposition property.

[0016] (2) The present invention designs a perovskite B site composed of a combination of a stable valence transition metal ion and a plurality of multivalent active transition metal ions, and simultaneously adopts a reducing condition formed by a combination of high temperature and a reducing atmosphere, which can regulate the precipitation of a trace amount of active transition metal on the surface, form a nano-alloy in situ, and can self-assemble with carbonate species to form composite nanoparticles, thereby obtaining a higher surface electrocatalytic activity and charge transfer activity.

[0017] (3) Since the nanocomposite phase is generated in situ on the micron skeleton, the nanostructure and the micron skeleton will have high chemical compatibility and thermal matching. During long-term operation, it will have high structural stability and will not easily suffer from problems such as agglomeration and coarsening.

[0018] The method of the present invention can realize high-performance solid oxide batteries in a carbon-containing atmosphere. The obtained self-assembled carbonate & alloy-perovskite electrode material has electrocatalytic hydrocarbon fuel oxidation reaction activity, carbon dioxide reduction reaction activity, and long-term stability in a carbon-containing atmosphere, which is conducive to promoting the development and application of solid oxide batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The self-assembled catalyst Sr2Mg prepared in Example 1 of the present invention 0.05 Fe 1.5 Mo 0.3 Ni 0.25 O 6-δ Scanning transmission electron microscopy images;

[0020] Figure 2 The self-assembled catalyst Sr2Mg prepared in Example 1 of the present invention 0.05 Fe 1.5 Mo 0.3 Ni 0.25 O 6-δ Current-voltage curve. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the invention claimed for protection, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0022] A method for preparing a self-assembled carbonate & alloy-perovskite electrode material comprises the following steps:

[0023] Preparation of Sr2A by self-combustion method x Fe 1.5 Mo 0.3 B y O 6-δ The initial powder is calcined at 850-1250℃ for 1-10h to obtain Sr2A x Fe 1.5 Mo 0.3 B y O 6-δFinal powder; wherein x=0.01-0.20, y=0.20-0.35; position A is one of potassium, sodium, magnesium, and calcium; position B is one or two of nickel, copper, iron, zinc, and cobalt;

[0024] Sr2A x Fe 1.5 Mo 0.3 B y O 6-δ The final powder was treated with solution and high temperature reduction. x Fe 1.5 Mo 0.3 B y O 6-δ The perovskite electrode surface is self-assembled and modified with carbonate and alloy nanoparticles to obtain Sr2A nanostructured in situ on the micro-skeleton surface. x Fe 1.5 Mo 0.3 B y O 6-δ Electrode material; the solution treatment process is to Sr2A x Fe 1.5 Mo 0.3 B y O 6-δ The final powder is placed in a specific solution and allowed to stand for 2 to 18 hours, filtered and dried, and then placed at 500 to 800° C. for calcination for 2 hours, and the above-mentioned standing and calcination processes are repeated 1 to 3 times; wherein the specific solution is a carbon dioxide solution, or an acetic acid solution, or a mixed solution of ethanol and water, and the volume fraction of ethanol is 0 to 90 vol%; the high-temperature reduction process is to place the final powder after solution treatment in a mixed gas for 2 to 12 hours, and the mixed gas is a mixed gas of carbon monoxide, carbon dioxide and nitrogen, wherein the volume fraction of carbon monoxide is 10 to 50 vol%, the volume fraction of carbon dioxide is 5 to 20 vol%, and the volume fraction of nitrogen is 20 to 85 vol%; the flow rate is 10 to 80 mL / min; finally, calcination is performed at 650 to 800° C. for 0.5 to 4 hours.

[0025] Example 1

[0026] A method for preparing a self-assembled carbonate & alloy-perovskite electrode material comprises the following steps:

[0027] (1) Preparation of Sr(NO3)2, Mg(NO3)3·6H2O, Fe(NO3)2·9H2O, (NH4)6Mo7O 24 ·4H2O, Ni(NO3)2·6H2O mixed solution and mixed with citric acid and EDTA solution; heated and stirred at 80℃ until gelatinous, then ignited in a watch glass to obtain Sr2Mg 0.05 Fe 1.5 Mo0.3 Ni 0.25 O 6-δ The initial powder was then calcined at 1200℃ for 6h to obtain Sr2Mg 0.05 Fe 1.5 Mo 0.3 Ni 0.25 O 6-δ Final powder. Among them, Sr(NO3)2, Mg(NO3)3·6H2O, Fe(NO3)2·9H2O, (NH4)6Mo7O 24 The molar ratio of ·4H2O and Ni(NO3)2·6H2O is 2.00:0.05:1.50:0.30:0.25.

[0028] (2) Sr2Mg in step (1) 0.05 Fe 1.5 Mo 0.3 Ni 0.25 O 6-δ The final powder was allowed to stand in a mixed solution of ethanol and water (ethanol volume fraction is 50 vol%) for 2 h, filtered and dried, and then calcined at 600° C. for 2 h. The above standing and calcining process was repeated twice.

[0029] (3) Sr2Mg treated in step (2) 0.05 Fe 1.5 Mo 0.3 Ni 0.25 O 6-δ The final powder was placed in a mixture of carbon monoxide, carbon dioxide and nitrogen for 2 hours, wherein the volume fraction of carbon monoxide was 25 vol%, the volume fraction of carbon dioxide was 10 vol%, and the volume fraction of nitrogen was 65 vol%; the flow rate was 30 mL / min; and then calcined at 700 ° C for 1.0 h to obtain the fuel electrode Sr2Mg 0.05 Fe 1.5 Mo 0.3 Ni 0.25 O 6-δ , microstructure such as Figure 1 As shown, a large number of nanoparticles are attached to the surface of micron particles.

[0030] The fuel electrode catalyst Sr2Mg prepared by the above method 0.05 Fe 1.5 Mo 0.3 Ni 0.25 O 6-δ Conduct electrochemical performance tests and obtain current-voltage curves such as Figure 2 As shown, the electrolysis current density at 650℃ can reach 1.6A cm -2 , and can operate stably for more than 50 hours, indicating that the fuel electrode has high battery performance and stability.

[0031] Example 2

[0032] A method for preparing a self-assembled carbonate & alloy-perovskite electrode material comprises the following steps:

[0033] (1) Preparation of Sr(NO3)2, Ca(NO3)3·4H2O, Fe(NO3)2·9H2O, (NH4)6Mo7O 24 ·4H2O, Ni(NO3)2·6H2O mixed solution and mixed with citric acid and EDTA solution. Stir and heat at 80℃ until it becomes gel, then ignite on a watch glass to obtain Sr2Ca 0.05 Fe 1.5 Mo 0.3 Ni 0.2 O 6-δ Initial powder, then calcined at 1200℃ for 6h to obtain Sr2Ca 0.05 Fe 1.5 Mo 0.3 Ni 0.2 O 6-δ The final powder. Among them, Sr(NO3)2, Ca(NO3)3·4H2O, Fe(NO3)2·9H2O, (NH4)6Mo7O 24 The molar ratio of ·4H2O and Ni(NO3)2·6H2O is 2.00:0.05:1.50:0.30:0.20.

[0034] (2) Sr2Ca in step (1) 0.05 Fe 1.5 Mo 0.3 Ni 0.2 O 6-δ The final powder was allowed to stand in a mixed solution of ethanol and water (ethanol volume fraction is 50 vol%) for 2 h, filtered and dried, and then calcined at 600° C. for 2 h. The above standing and calcining process was repeated twice.

[0035] (3) Sr2Ca treated in step (2) 0.05 Fe 1.5 Mo 0.3 Ni 0.2 O 6-δ The final powder was placed in a mixture of carbon monoxide, carbon dioxide and nitrogen for 2 hours, wherein the volume fraction of carbon monoxide was 35 vol%, the volume fraction of carbon dioxide was 5 vol%, and the volume fraction of nitrogen was 60 vol%; the flow rate was 30 mL / min; and then calcined at 700 ° C for 1.0 h to obtain the fuel electrode Sr2Ca 0.05 Fe 1.5 Mo 0.3 Ni 0.2 O 6-δ .

[0036] The fuel electrode catalyst Sr2Ca 0.05 Fe 1.5 Mo 0.3 Ni 0.2 O 6-δ Electrochemical performance test: the electrolysis current density at 650℃ can reach 1.5A cm -2 , and can operate stably for more than 50 hours, indicating that the fuel electrode has high battery performance and stability.

[0037] Example 3

[0038] A method for preparing a self-assembled carbonate & alloy-perovskite electrode material comprises the following steps:

[0039] (1) Preparation of Sr(NO3)2, Ba(NO3)3·6H2O, Fe(NO3)2·9H2O, (NH4)6Mo7O 24 ·4H2O, Ni(NO3)2·6H2O mixed solution and mixed with citric acid and EDTA solution; heated and stirred at 80℃ until gelatinous, then ignited in a watch glass to obtain Sr2Ba 0.02 Fe 1.5 Mo 0.3 Ni 0.3 O 6-δ Initial powder, then calcined at 1200℃ for 6h to obtain Sr2Ba 0.02 Fe 1.5 Mo 0.3 Ni 0.3 O 6-δ Final powder. Among them, Sr(NO3)2, Mg(NO3)3·6H2O, Fe(NO3)2·9H2O, (NH4)6Mo7O 24 The molar ratio of ·4H2O and Ni(NO3)2·6H2O is 2.00:0.02:1.50:0.30:0.30.

[0040] (2) Sr2Ba from step (1) 0.02 Fe 1.5 Mo 0.3 Ni 0.3 O 6-δ The final powder was allowed to stand in a mixed solution of ethanol and water (ethanol volume fraction is 50 vol%) for 2 h, filtered and dried, and then calcined at 600° C. for 2 h. The above standing and calcining process was repeated twice.

[0041] (3) Sr2Ba treated in step (2) 0.02 Fe 1.5 Mo 0.3 Ni 0.3 O6-δ The final powder was placed in a mixture of carbon monoxide, carbon dioxide and nitrogen for 2 hours, wherein the volume fraction of carbon monoxide was 35 vol%, the volume fraction of carbon dioxide was 5 vol%, and the volume fraction of nitrogen was 60 vol%; the flow rate was 30 mL / min; and then calcined at 700 ° C for 1.0 h to obtain the fuel electrode Sr2Ba 0.02 Fe 1.5 Mo 0.3 Ni 0.30 O 6-δ .

[0042] The fuel electrode catalyst Sr2Ba prepared by the above method 0.02 Fe 1.5 Mo 0.3 Ni 0.3 O 6-δ Electrochemical performance test: the electrolysis current density at 650℃ can reach 1.2A cm -2 , and can operate stably for more than 50 hours, indicating that the fuel electrode has high battery performance and stability.

[0043] The present invention designs and synthesizes a perovskite oxide with excessive doping of alkaline metal ions at the A position and regulated composition and ratio of transition metal ions at the B position. The perovskite fuel electrode catalyst powder has high activity in hydrocarbon fuel and carbon dioxide conversion adsorption, dissociation and catalytic reaction. At the same time, the perovskite skeleton has high oxygen transmission activity, which is conducive to promoting the development and application of hydrocarbon fuel type SOFC and SOEC high temperature electrolysis of carbon dioxide containing gas. The present invention further combines solution reaction and high temperature reaction for the fuel electrode catalyst, and the surface structure reacts in situ at the molecular level and self-assembles into a stable nanocomposite system. The structure is conducive to surface gas adsorption and dissociation. At the same time, carbonate provides anti-carbon deposition stabilization and carbon-oxygen species transfer activity, and the alloy provides electron transfer and catalysis.

[0044] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by technicians in this technical field within the essential scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A method for preparing a self-assembled carbonate & alloy-perovskite electrode material, characterized in that: The steps include: Preparation of Sr2A by self-combustion method x Fe 1.5 Mo 0.3 B y O 6-δ The initial powder is calcined at 850-1250℃ for 1-10h to obtain Sr2A x Fe 1.5 Mo 0.3 B y O 6-δ Final powder; Sr2A x Fe 1.5 Mo 0.3 B y O 6-δ The final powder was treated with solution and high temperature reduction. x Fe 1.5 Mo 0.3 B y O 6-δ The perovskite electrode surface is self-assembled and modified with carbonate and alloy nanoparticles to obtain Sr2A nanostructured in situ on the micro-skeleton surface. x Fe 1.5 Mo 0.3 B y O 6-δ Electrode material.

2. A method for preparing a self-assembled carbonate & alloy-perovskite electrode material according to claim 1, characterized in that: x=0.01-0.20, y=0.20-0.35; the A position is one of potassium, sodium, magnesium, and calcium; the B position is one or two of nickel, copper, iron, zinc, and cobalt.

3. A method for preparing a self-assembled carbonate & alloy-perovskite electrode material according to claim 1, characterized in that: The solution treatment process is to convert Sr2A x Fe 1.5 Mo 0.3 B y O 6-δ The final powder is placed in a specific solution and allowed to stand for 2 to 18 hours, filtered and dried, and then calcined at 500 to 800° C. for 2 hours, and the above-mentioned standing and calcining processes are repeated 1 to 3 times; wherein the specific solution is a carbon dioxide solution, or an acetic acid solution, or a mixed solution of ethanol and water, and the volume fraction of ethanol is 0 to 90 vol%.

4. A method for preparing a self-assembled carbonate & alloy-perovskite electrode material according to claim 1, characterized in that: The high-temperature reduction process is to place the final powder after solution treatment in a mixed gas for 2 to 12 hours, wherein the mixed gas is a mixture of carbon monoxide, carbon dioxide and nitrogen, wherein the volume fraction of carbon monoxide is 10 to 50 vol%, the volume fraction of carbon dioxide is 5 to 20 vol%, and the volume fraction of nitrogen is 20 to 85 vol%; the flow rate is 10 to 80 mL / min; finally, calcining is performed at 650 to 800° C. for 0.5 to 4 hours.

5. A self-assembled carbonate & alloy-perovskite electrode material prepared by the method described in any one of claims 1 to 4.

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