CN100534906C - Method for synthesizing middle and low temperature oxygen ion conductor material - Google Patents

Abstract

The invention provides a method for synthesizing a low-temperature oxygen ion conductor material in the Bi ₂ Me _xy Me' _x+y V _1-x O _5.35-δ system of Aurivillus structure. The method is to complex the bismuth nitrate and ethylenediaminetetraacetic acid in deionized water according to the stoichiometric ratio of the synthetic product, and then add citric acid, copper or cobalt nitrate or cobalt carbonate and partial tungsten Ammonium acid or ammonium molybdate, after stirring, a clear and transparent precursor solution is obtained, and then heated to make it concentrated, expanded and coked to form a fluffy primary powder, and the primary powder is heat-treated to obtain a 100-200nm Ultrafine synthetic powder. The synthesis process of the invention is simple and easy, the synthesis time is short, and the synthetic product particles are fine and uniform, and can be used in oxygen pumps, electrochemical sensors, oxygen separation membranes, etc. used in the medium and low temperature range of 300-600 ° C, and has a wide range of applications. Application prospect.

Description

A kind of synthetic method of middle and low temperature oxygen ion conductor material

technical field

The invention relates to the field of solid-state ion conductors, in particular to a synthesis of Bi ₂ Me _xy Me' _x+y V _1-x O _5.35-δ (Me=Cu or Co, Me'=W or Mo, x =0.1～0.2, y=0.02～0.2, _δ is a non-stoichiometric oxygen) synthesis method of low-temperature oxygen ion conductor material in the system.

Background technique

Bi ₂ VO _5.5 ^is _a new medium _and low temperature oxygen ion conductor material developed _in recent ^years _. ) layered structure formed by alternating arrangement. There are a large number of oxygen vacancies in the vanadyl perovskite layers connected by [VO ₆ ] octahedrons sharing corners, resulting in high oxygen ion conductivity in the direction parallel to the vanadyl perovskite layers. Below the melting point of Bi ₂ VO _5.5 (870°C), Bi ₂ VO _5.5 has a series of complex phase transitions, including monoclinic α phase (temperature < 430°C), orthorhombic β phase (430°C-570°C) and Tetragonal γ phase (temperature > 570°C). Among them, high temperature γ-Bi ₂ VO _5.5 has the best oxygen ion conductivity. Using other metal ions (such as copper ions, cobalt ions, etc.) to replace part of the V ions in Bi ₂ VO _5.5 to form a Bi ₂ Me _x V _1-x O _5.35-δ solid solution can obtain a high conductivity γ phase at room temperature , its oxygen ion conductivity reaches the level of 10 ^-3 -10 ^-1 S·cm ^-1 in the medium and low temperature range of 300-600°C, which makes the Bi ₂ Me _x V _1-x O _5.35-δ system in the oxygen pump , electrochemical sensors, oxygen separation membranes and other aspects have a wide range of uses. Recent studies have shown that the composite substitution of some V ions in Bi ₂ VO _5.5 with two different metal ions can further improve the oxygen ion conductivity of the material.

At present, the conventional solid-phase synthesis method is mainly used to prepare such medium and low temperature oxygen ion conductor materials. The main process is: mix Bi ₂ O ₃ , V ₂ O ₅ and other metal oxides according to the stoichiometric ratio, ball mill, and then Carry out multiple calcining at 650～800 ℃, until obtaining the solid-phase synthesis product of single Aurivillus structure (see J.Yan, M.Greenblatt, Solid State Ionics, 1995, 81:225 and JRDygas, M.Malys, F.Krok, W. Wrobel, A. Kozanecka and I. Abrahams, Solid State Ionics, 2005, 178:2085). For this kind of medium and low temperature oxygen ion conductor materials, it usually takes a long time (tens of hours to tens of hours) of repeated solid-phase synthesis processes to obtain a synthetic product with a single Aurivillus structure, which places great emphasis on its research and development. Applications are difficult. Therefore, there is a need to explore new and efficient synthetic methods for such intermediate and low temperature oxygen ion conductor materials.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method for easily synthesizing a low-temperature oxygen ion conductor material in the Bi ₂ Me _xy Me' _x+y V _1-x O _5.35-δ system with an Aurivillus structure, and to synthesize The phase purity of the product is high.

The technical scheme that the present invention adopts to solve its technical problem is: adopt and comprise the following steps to synthesize a kind of low-temperature oxygen ion conductor material in the Bi ₂ Me _xy Me' _y V _1-x O _5.35-δ system with Aurivillus structure, in the molecular formula, Me=Cu or Co, Me'=W or Mo, x=0.1-0.2, y=0.02-0.2, _δ is non-stoichiometric oxygen.

Complexation: Complexation of bismuth nitrate or carbonate with ethylenediaminetetraacetic acid in deionized water to obtain a clear and transparent aqueous solution. During complexation, the molar ratio of Bi ions to ethylenediaminetetraacetic acid is 1:0.5-2, preferably 1:1.2-2.

(2) Preparation of precursor solution: add citric acid and copper or cobalt nitrate or cobalt carbonate in the resulting aqueous solution, then add ammonium metavanadate, and ammonium metatungstate or ammonium molybdate; After heating and stirring at 30-60° C. for 1-4 hours, a clear and transparent precursor solution is obtained. In the obtained precursor solution, the molar ratio of citric acid to the total amount of various metal ions is 1-4:1, and the pH value of the solution is 7-10.

(3) Preparation of the primary product: the precursor solution is heated to cause concentration, expansion, and coking changes to form a fluffy primary powder. When heating the precursor solution, the process conditions are: heating temperature 150-350° C., heating time 0.5-10 hours.

(4) Preparation of synthetic products: the primary powder is heat-treated in a muffle furnace to obtain an ultrafine synthetic powder with a single Aurivillus structure. When the primary powder is heat-treated in a muffle furnace, the process conditions are: heat treatment temperature 450-600°C, time 0.5-2 hours.

The beneficial effects of the invention are: the synthesis process is simple and easy, the synthesis temperature is low, the synthesis time is short, the synthesis process is easy to control, and the repeatability is good. The X-ray diffraction (XRD) test confirmed that the synthesized product has a single Aurivillus structure and is a tetragonal γ phase. It is also confirmed by a field emission scanning electron microscope (FESEM) test that the synthesized product has fine and uniform particles with a particle size of 100-200nm. The powder synthesized by the method can be sintered at 550-700° C. for 0.5-4 hours to obtain a dense ceramic rod product. The oxygen ion conductivity of the ceramic samples was tested by AC impedance spectroscopy, and it was confirmed that the oxygen ion conductivity ^of the ceramic samples reached the level of 10 ^-2 S·cm ^-1 at 300°C and 10 -2 at 600°C ¹ S cm ^-1 level. The product synthesized by the method can be used in oxygen pumps, electrochemical sensors, oxygen separation membranes and the like used in the medium and low temperature range of 300-600 DEG C, and has broad application prospects.

Description of drawings

Fig. 1 is the XRD spectrum of the Bi ₂ Cu _0.05 W _0.05 V _0.9 O _5.35-δ ultrafine powder of Example 1.

Fig. 2 is a FESEM photo of the Bi ₂ Cu _0.05 W _0.05 V _0.9 O _5.35-δ ultrafine powder of Example 1.

Fig. 3 is a SEM photo of a ceramic sample prepared by using the Bi ₂ Cu _0.05 W _0.05 V _0.9 O _5.35-δ ultrafine powder in Example 1.

Fig. 4 is the Arrenhius relationship curve of the oxygen ion conductivity of the ceramic sample prepared by using the Bi ₂ Cu _0.05 W _0.05 V _0.9 O _5.35-δ ultrafine powder in Example 1.

Figure 1 shows that the position and relative intensity of each diffraction peak in the XRD pattern of the synthesized product are consistent with the standard JCPDS card (44-0358) of γ-Bi ₂ VO _5.5 , indicating that the synthesized product has a single AurivillIus structure, which is tetragonal γ Mutually.

Figure 2 illustrates: the particles of the synthetic powder are approximately spherical, there is no obvious agglomeration phenomenon between the particles, the particle size is uniform, and the particle size is mainly distributed in the range of 100-200nm.

Figure 3 shows that the ceramic samples prepared by using synthetic powders are tightly bonded between grains and have a compact microstructure.

Figure 4 illustrates: the oxygen ion conductivity of ceramic samples in the temperature range of 200-600 ° C is measured by AC impedance spectroscopy, and the Arrenhius relationship curve of oxygen ion conductivity of ceramic samples is obtained by plotting log (σT) against 1000/T . The oxygen ion conductivity of the ceramic sample reaches 1.8×10 ^-2 S·cm ^-1 at 300°C and 1.4×10 ^-1 S·cm ^-1 at 600°C

Detailed ways

The invention provides a method for synthesizing a low-temperature oxygen ion conductor material in a Bi ₂ Mc _xy Me' _y V _1-x O _5.35-δ system with an Aurivillus structure. The steps adopted include complexation, preparation of a precursor solution, Preparation of primary products, preparation of synthetic products.

The present invention will be further described below in conjunction with embodiment, but does not limit the present invention.

Example 1:

(1) Complexation: Put bismuth nitrate hydrate Bi(NO ₃ ) ₃ ·5H ₂ O and ethylenediaminetetraacetic acid in a beaker at a molar ratio of 1:1.2 between Bi ³⁺ and ethylenediaminetetraacetic acid , add an appropriate amount of deionized water, and stir to obtain a clear and transparent aqueous solution;

(2) Preparation of precursor solution: weigh a certain amount of ammonium metavanadate NH ₄ VO ₃ , hydrated copper nitrate Cu(NO ₃ ) ₃ according to the stoichiometric ratio of Bi ₂ Cu _0.05 W _0.05 V _0.9 O _5.35- δ 3H ₂ O and ammonium metatungstate, add citric acid according to the molar ratio of citric acid to the total amount of various metal ions is 3:1, add to the aqueous solution obtained in the previous step, and stir at 40°C for 2 After hours, a clear and transparent precursor solution was obtained, and the pH value of the precursor solution was adjusted to 8 with ammonia water;

(3) Preparation of the primary product: heating the precursor solution at 300°C for 1 hour, during the heating process, the precursor solution gradually undergoes changes such as concentration, expansion, and coking to form a fluffy primary powder;

(4) Preparation of synthetic products: Put the primary powder in a crucible and send it into a muffle furnace, heat it to 500°C in an air atmosphere and keep it warm for 1 hour to obtain a deep yellow synthetic powder.

Example 2:

(1) Complexation: Put bismuth nitrate hydrate Bi(NO ³ ) ₃ ·5H ₂ O and ethylenediaminetetraacetic acid in a beaker at a molar ratio of 1:1 between Bi ₃₊ and ethylenediaminetetraacetic acid , add an appropriate amount of deionized water and stir until a clear and transparent aqueous solution is obtained;

(2) Preparation of precursor solution: Weigh a certain amount of ammonium metavanadate NH ₄ VO ₃ , hydrated cobalt nitrate Co(NO ₃ ) ₃ according to the stoichiometric ratio of Bi ₂ Co _0.08 W _0.02 V _0.9 O _5.35- δ 6H ₂ O and ammonium metatungstate, add citric acid at a ratio of 2.5:1 molar ratio of citric acid to the total amount of various metal ions, add it to the aqueous solution obtained in the previous step, and stir at 50°C for 1 hour Finally, a clear and transparent precursor solution is obtained, and the pH value of the precursor solution is adjusted to 9 with ammonia water;

(3) Preparation of the primary product: Put the precursor solution in an oven, adjust the temperature of the oven to 150°C, and the precursor solution gradually undergoes changes such as concentration, expansion, and coking during the 10-hour heating process to form a fluffy primary powder;

(4) Preparation of synthetic products: Put the primary powder in a crucible and send it into a muffle furnace, heat it to 550° C. in an air atmosphere and keep it warm for 1.5 hours to obtain a brown synthetic powder.

Example 3:

(1) Complexation: Put bismuth nitrate hydrate Bi(NO ³ ) ₃ ·5H ₂ O and ethylenediaminetetraacetic acid in a beaker at a molar ratio of 1:2 _of Bi 3+ and ethylenediaminetetraacetic acid , add an appropriate amount of deionized water and stir until a clear and transparent aqueous solution is obtained;

(2) Preparation of precursor solution: Weigh a certain amount of ammonium metavanadate NH ₄ VO ₃ , hydrated cobalt nitrate Cu(NO ₃ ) ₃ according to the stoichiometric ratio of Bi ₂ Cu _0.02 Mo _0.08 V _0.9 O _5.35- δ 3H ₂ O and ammonium molybdate, add citric acid at a ratio of 1.5:1 molar ratio of citric acid to the total amount of various metal ions, add it to the aqueous solution obtained in the previous step, and stir at 50°C for 4 hours A clear and transparent precursor solution is obtained, and the pH value of the precursor solution is adjusted to 10 with ammonia water;

(2) Preparation of the primary product: heating the precursor solution at 300°C for 1 hour, during the heating process, the precursor solution gradually undergoes changes such as concentration, expansion, and coking to form a fluffy primary powder;

(4) Preparation of the synthetic product: the primary powder is placed in a crucible and sent into a muffle furnace, heated to 600°C in an air atmosphere and kept for 2 hours to obtain a yellow synthetic powder.

Example 4:

(1) Complexation: Put bismuth nitrate hydrate Bi(NO ³ ) ₃ ·5H ₂ O and ethylenediaminetetraacetic acid in a beaker at a molar ratio of 1:1 between Bi ₃₊ and ethylenediaminetetraacetic acid , add an appropriate amount of deionized water and stir until a clear and transparent aqueous solution is obtained;

(2) Preparation of precursor solution: weigh a certain amount of ammonium metavanadate NH ₄ VO ₃ , hydrated cobalt nitrate Co(NO ₃ ) ₃ according to the stoichiometric ratio of Bi ₂ Co _0.05 Mo _0.05 V _0.9 O _5.35- δ 6H ₂ O and ammonium molybdate, add citric acid according to the molar ratio of citric acid to the total amount of various metal ions is 2:1, add to the aqueous solution obtained in the previous step, stir at 60°C for 1 hour A clear and transparent precursor solution was obtained, and the pH value of the precursor solution was adjusted to 8 with ammonia water;

(3) Preparation of the primary product: heating the precursor solution at 250°C for 3 hours, during the heating process, the precursor solution gradually undergoes changes such as concentration, expansion, and coking to form a fluffy primary powder;

(4) Preparation of synthetic products: Put the primary powder in a crucible and send it into a muffle furnace, heat it to 500°C in an air atmosphere and keep it warm for 1 hour to obtain a brown synthetic powder.

Example 5:

(1) Complexation: Put bismuth nitrate hydrate Bi(NO ₃ ) ₃ ·5H ₂ O and ethylenediaminetetraacetic acid in a beaker at a molar ratio of 1:0.5 between Bi ³⁺ and ethylenediaminetetraacetic acid , add an appropriate amount of deionized water and stir until a clear and transparent aqueous solution is obtained;

(2) Preparation of precursor solution: Weigh a certain amount of ammonium metavanadate NH ₄ VO ₃ and cobalt carbonate CoCO ₃ according to the stoichiometric ratio of Bi ₂ Co _0.1 V _0.9 O _5.35-δ , The molar ratio of the total amount of ions is to add citric acid in a ratio of 1:1, add it to the aqueous solution obtained in the previous step, and stir at 30°C for 0.5 hours to obtain a clear and transparent precursor solution, and adjust the concentration of the precursor solution with ammonia water. The pH value is 7;

(3) Preparation of the primary product: Put the precursor solution in an oven, adjust the temperature of the oven to 150°C, and the precursor solution gradually undergoes changes such as concentration, expansion, and coking during the 10-hour heating process to form a fluffy primary powder;

(4) Preparation of synthetic products: Put the primary powder in a crucible and send it into a muffle furnace, heat it to 450°C in an air atmosphere and keep it warm for 0.5 hours to obtain a brown synthetic powder.

Embodiment 6:

(1) Complexation: Put bismuth nitrate hydrate Bi(NO ₃ ) ₃ ·5H ₂ O and ethylenediaminetetraacetic acid in a beaker at a molar ratio of 1:0.5 between Bi ³⁺ and ethylenediaminetetraacetic acid , add an appropriate amount of deionized water and stir until a clear and transparent aqueous solution is obtained;

(2) Preparation of precursor solution: Weigh a certain amount of ammonium metavanadate NH ₄ VO ₃ and copper carbonate CoCO ₃ according to the stoichiometric ratio of Bi ₂ Cu _0.2 V _0.8 O _5.35-δ , and mix them with citric acid and various metals The molar ratio of the total amount of ions is 4: 1. Add citric acid, add it to the aqueous solution obtained in the previous step, and stir at 30°C for 0.5 hours to obtain a clear and transparent precursor solution. Adjust the concentration of the precursor solution with ammonia water. The pH value is 7;

(3) Preparation of the primary product: Put the precursor solution in an oven, adjust the temperature of the oven to 350°C, and the precursor solution gradually undergoes changes such as concentration, expansion, and coking during the 0.5-hour heating process to form a fluffy primary powder;

(4) Preparation of synthetic products: Put the primary powder in a crucible and send it into a muffle furnace, heat it to 500°C in an air atmosphere and keep it warm for 0.5 hours to obtain a brown synthetic powder.

The synthetic powders obtained in the above examples are tested and analyzed, and results similar to those in Example 1 (see Figure 1 and Figure 2) can be obtained: they have a single Aurivillus structure, which is a tetragonal γ phase, and the powder particles are approximately Spherical, there is no obvious agglomeration phenomenon between particles, the particle size is uniform, and the particle size is mainly distributed in the range of 100-200nm.

Claims (5)

1. the synthetic method of cryogenic oxygen ionic conductor material in a kind is characterized in that a kind of Bi of the Aurivillus of having structure ₂Me _X-yMe ' _yV _1-xO _5.35-δThe synthetic method of cryogenic oxygen ionic conductor material in the system, in the molecular formula, Me=Cu or Co, Me '=W or Mo, x=0.1～0.2, y=0.02～0.2, δ is a nonstoichiometry oxygen; Said method comprising the steps of:

(1) complexing: the nitrate of bismuth or carbonate and ethylenediamine tetraacetic acid (EDTA) are carried out complexing in deionized water, obtain the aqueous solution of clear;

(2) preparation of precursor solution: in the resulting aqueous solution, add citric acid and the nitrate of copper or cobalt or the carbonate of cobalt, add ammonium meta-vanadate then, and ammonium metawolframate or ammonium molybdate; After heating under 30～60 ℃ of temperature and stirring 1～4 hour, obtain the precursor solution of clear;

(3) preparation of primary products: precursor solution is heated, make it take place to concentrate, expansion, coking change, and forms fluffy elementary powder;

(4) preparation of sintetics: in retort furnace, elementary powder is heat-treated, obtain having the ultra tiny synthetic powder of single Aurivillus structure.

2. the synthetic method of cryogenic oxygen ionic conductor material in according to claim 1, it is characterized in that: when the nitrate of bismuth or carbonate and ethylenediamine tetraacetic acid (EDTA) carried out complexing, the mol ratio of Bi ion and ethylenediamine tetraacetic acid (EDTA) was 1: 1.2～2.

3. the synthetic method of cryogenic oxygen ionic conductor material in according to claim 1 is characterized in that: resulting precursor solution, and wherein the mol ratio of citric acid and each metal ion species total amount is 1～4: 1, the pH value of this solution is 7～10.

4. the synthetic method of cryogenic oxygen ionic conductor material in according to claim 1, when it is characterized in that precursor solution heated, its processing condition are: 150～350 ℃ of Heating temperatures, 0.5～10 hour heat-up time.

5. the synthetic method of cryogenic oxygen ionic conductor material in according to claim 1, when it is characterized in that in retort furnace elementary powder heat-treated, its processing condition are: 450～600 ℃ of thermal treatment temps, 0.5～2 hour time.

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