Method for ultrafast synthesis of pyrochlore type and perovskite type oxides based on Joule heat

Abstract

The invention discloses a method for ultrafast synthesizing pyrochlore type and perovskite type oxides based on Joule heat, which comprises the following steps of: firstly, obtaining a solid precursor by adopting a coprecipitation method, then quickly heating the solid precursor to 700-800 DEG C by using a Joule heat shock technology, cooling to room temperature, and circulating heating-cooling operation for a plurality of times to prepare a series of pyrochlore type (A2B2O7) and perovskite type (ABO3) oxides; the synthesis time is extremely short (lt; the method has the advantages of high yield (more than 2500g / h), high energy efficiency and potential to realize the purpose of high-flux synthesis, and has a good industrial production basis and a wide application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of preparation of pyrochlore (A2B2O7) and perovskite (ABO3) oxides, and in particular to a novel method for ultrafast synthesis of a series of pyrochlore (A2B2O7) and perovskite (ABO3) oxides based on Joule heat. Background Art

[0002] The chemical formula of pyrochlore-type oxides is usually A2B2O7, and the chemical formula of perovskite-type oxides is usually ABO3 (where A and B are metal ions).

[0003] A2B2O7 pyrochlore-type composite oxides have good thermal and chemical stability, appropriate surface acid and base centers, abundant oxygen vacancies and excellent oxygen ion conductivity. Its structure is open, and the A and B positions can be widely replaced and combined by ions with similar properties. It is a new type of inorganic functional material that has attracted much attention in recent decades.

[0004] Perovskite ABO3 has a variety of application fields. First, it has great potential in the field of solar cells. Perovskite materials can efficiently convert solar energy into electrical energy, so they are widely studied for the preparation of efficient solar cells (AngewandteChemie International Edition, 2022, 61 (11): e202114793); secondly, perovskites also have important applications in optoelectronic devices, luminescent materials and photocatalysis (ACS Applied Electronic Materials, 2022, 4 (2): 547-567; Advanced Electronic Materials, 2023, 9 (9): 2201271; Journal of Materials Chemistry A, 2023). Since the structure and optical properties of perovskites are adjustable, the diversity and functionality of materials can be achieved by controlling the synthesis method and structural design. In addition, perovskite can also be used in energy storage devices, sensors, catalysts and biomedicine (Perovskite in the energy storage device; Microchemical Journal, 2023, 191: 108924; Chinese Journal of Catalysis, 2023, 50: 109-125; Biomaterials Translational, 2023, 4 (3): 131), providing new ideas and solutions for solving practical problems.

[0005] People have been pursuing a method for synthesizing metal oxide catalysts with lower time cost, lower energy cost and higher yield. Although pyrochlore-type A2B2O7 and perovskite-type ABO3 oxides have significant cost advantages over commercial noble metal-based catalysts, the methods used to prepare them have become obstacles to commercialization. Direct high-temperature solid-phase method is a conventional method, which is conducive to obtaining a pure phase with good crystallization, but phase formation and crystallization require high temperature, long reaction time, high time cost and low energy efficiency (Advanced Functional Materials, 2017, 27 (7): 1604349.). Hydrothermal method is also a common technique for preparing highly dispersed and small particle size products, but it is not suitable for large-scale production (Journal of colloid and interface science, 2017, 503: 17-27). Traditional synthesis methods are either time-consuming and labor-intensive, or can only be used for small-batch synthesis. Therefore, it is urgent to develop a general method for low-cost, low-energy consumption, ultra-fast synthesis of pyrochlore-type (A2B2O7) and perovskite-type (ABO3) oxides.

[0006] In recent years, providing energy to the reaction system more directly through physical conditions has become one of the most important means to achieve rapid synthesis (Energy & Environmental Science, 2023, 16 (3): 1100-1110). Joule heating is a simple, energy-efficient method that has the potential to achieve the goal of high-throughput synthesis. When a large current passes through a conductive graphite plate, the graphite plate instantly generates a large amount of Joule heat, which quickly provides energy to the reaction system (Q = I 2Rt), so that the chemical reaction is completed in a very short time (Advanced Energy Materials, 2020, 10(33): 2001331). The simple device and transient heating characteristics make Joule heat suitable for the production of nano-micrometer-scale functional materials, such as high entropy alloys, high entropy oxides, lithium oxide positive electrode materials, single-atom catalyst materials, uniform-sized all-nanocluster catalysts, and metastable nanomaterials such as transition metal carbide catalysts (Science, 2018, 359(6383): 1489-1494; Advanced Functional Materials, 2021, 31(21): 2010561; Advanced Materials, 2023, 35(2): 2208974; ACS Catalysis, 2023, 14: 183-191; ACS Catalysis, 2023, 13(14): 9777-9791; Nature Communications, 2022, 13(1): 262). It has been extended to the synthesis of small molecules (Nature, 2022, 605(7910):470-476). However, there are few reports on the synthesis of pyrochlore-type A2B2O7 and perovskite-type ABO3 oxide catalysts using Joule heating.

[0007] In view of this, we have developed a new method for ultrafast mass synthesis of a series of pyrochlore (A2B2O7) and perovskite (ABO3) oxides based on Joule heat. The unique heating method of Joule heat is used to realize the controllable synthesis of pyrochlore (A2B2O7) and perovskite (ABO3) oxides, and its synthesis cycle is reduced to the second level, so as to achieve the purpose of high-throughput synthesis of a series of pyrochlore (A2B2O7) and perovskite (ABO3) oxides. At the same time, the series of pyrochlore (A2B2O7) and perovskite (ABO3) oxides prepared by the present invention have the advantages of simple operation, extremely low energy consumption, and high-throughput synthesis. In addition, the preparation method provided in this application is simple in process, low in cost, safe and efficient, and has a good industrial production foundation and broad application prospects. Summary of the invention

[0008] In view of the shortcomings of the prior art, the present invention provides a new method for ultrafast synthesis of a series of pyrochlore (A2B2O7) and perovskite (ABO3) oxides based on Joule heat. The method is simple and controllable, with an extremely short preparation cycle, extremely high yield, and extremely high energy efficiency. It has the potential to achieve the purpose of high-throughput synthesis, and has a good industrial production foundation and broad application prospects.

[0009] The technical solution of the present invention is as follows:

[0010] A method for ultrafast synthesis of pyrochlore-type and perovskite-type oxides based on Joule heat, comprising:

[0011] The metal source A and the metal source B are uniformly dispersed in deionized water to obtain a metal source solution, and an ammonium hydroxide solution is added dropwise to a pH of 9 under stirring, and the mixture is allowed to stand (2 h). The supernatant is poured out and centrifuged (9500 rpm, 5 min) to obtain a solid precursor; the obtained solid precursor is dried (80° C., 24 h), placed in a Joule heat device, and rapidly heated to 700-800° C. by pulse discharge to generate Joule heat in an air atmosphere, and then cooled to room temperature, and the heating-cooling operation is repeated several times to obtain the target product;

[0012] The metal elements in the metal source A and the metal source B are selected from at least two of lanthanum, zirconium, cerium, yttrium, samarium, gadolinium, aluminum, iron, and chromium; the metal source A and the metal source B can be in the form of metal nitrates, metal chlorides, metal oxides, metal stannates, etc.;

[0013] Preferably, the molar ratio of metal source A to metal source B is 1 to 2:1;

[0014] Preferably, the total feed ratio of deionized water to metal source A and metal source B is 200:10-20, mL / g;

[0015] Specifically, when the metal source A is selected from lanthanum nitrate, yttrium nitrate, cerium nitrate, samarium nitrate or gadolinium nitrate, the metal source B is selected from zirconium nitrate or cerium nitrate, and the metal source A is different from the metal source B, the target product obtained is a pyrochlore-type (A2B2O7) oxide; when the metal source A is selected from lanthanum nitrate, samarium nitrate or gadolinium nitrate, the metal source B is selected from aluminum nitrate, iron nitrate or chromium nitrate, the target product obtained is a perovskite-type (ABO3) oxide;

[0016] In addition, metal sources that are insoluble in deionized water can be dissolved by adding an appropriate amount of dilute nitric acid. For example, when preparing La2Zr2O7, when metal source A is lanthanum nitrate and metal source B is zirconium nitrate, they can be directly dissolved in deionized water; while when metal source A is lanthanum oxide and metal source B is zirconium oxide, an appropriate amount of dilute nitric acid needs to be added for full dissolution.

[0017] "Metal source A" and "Metal source B" have no special meanings, and are marked as "A" and "B" only to distinguish different types of metal sources;

[0018] Preferably, the heating-cooling operation cycle is 5 to 8 times;

[0019] The current of pulse discharge is 300-400 amperes, the single discharge time of pulse discharge is 5-8s, and the maximum temperature generated by Joule heat is 700-800°C; the power supply used for pulse discharge is DC power supply or AC power supply.

[0020] The beneficial effects of the present invention are:

[0021] The present invention reports for the first time the rapid synthesis of A2B2O7 and ABO3 series materials, which can be carried out in an air atmosphere by adjusting the pH of the solution to precipitate the metal, and has a very short synthesis time (<6s), high yield (>2500g / h), high energy efficiency, and great industrial prospects. The synthesized materials can be used in photovoltaics, methane coupling, and as carrier materials, etc.

[0022] The traditional method of preparing A2B2O7 and ABO3 requires long-term heat treatment in a furnace, slow heating and cooling process (at least several hours) to form a fine crystal structure. Obviously, long-term heating will lead to high energy consumption, high cost and low manufacturing efficiency. The present invention combines high heating / cooling rate (10 5 The Joule heat of 1000 ℃ / s) can achieve ultrafast reaction kinetics and ultrashort reaction time. In addition, the non-equilibrium nature of Joule heat is conducive to the preparation of heterostructure materials, which is also the creativity of this application. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 : The X-ray diffraction pattern of La2Zr2O7 shows that the diffraction peaks all correspond to the diffraction peaks of pure phase La2Zr2O7, indicating that La2Zr2O7 was successfully synthesized.

[0024] Figure 2 : The X-ray diffraction pattern of La2Ce2O7, its diffraction peaks all correspond to the diffraction peaks of pure phase La2Ce2O7, indicating that La2Ce2O7 was successfully synthesized.

[0025] Figure 3 : The X-ray diffraction pattern of Y2Zr2O7 shows that the diffraction peaks all correspond to the diffraction peaks of pure phase Y2Zr2O7, indicating that Y2Zr2O7 was successfully synthesized.

[0026] Figure 4 : The X-ray diffraction pattern of Ce2Zr2O7 shows that the diffraction peaks all correspond to the diffraction peaks of pure phase Ce2Zr2O7, indicating that Ce2Zr2O7 was successfully synthesized.

[0027] Figure 5 : The X-ray diffraction pattern of Sm2Zr2O7 shows that the diffraction peaks all correspond to the diffraction peaks of pure phase Sm2Zr2O7, indicating that Sm2Zr2O7 was successfully synthesized.

[0028] Figure 6 : The X-ray diffraction pattern of Gd2Zr2O7 shows that the diffraction peaks all correspond to the diffraction peaks of pure phase Gd2Zr2O7, indicating that Gd2Zr2O7 was successfully synthesized.

[0029] Figure 7: The X-ray diffraction pattern of LaAlO3 shows that the diffraction peaks all correspond to the diffraction peaks of pure phase LaAlO3, indicating that LaAlO3 was successfully synthesized.

[0030] Figure 8 : The X-ray diffraction pattern of LaFeO3 shows that the diffraction peaks all correspond to the diffraction peaks of pure phase LaFeO3, indicating that LaFeO3 was successfully synthesized.

[0031] Fig. 9 : The X-ray diffraction pattern of LaCrO3 shows that the diffraction peaks all correspond to the diffraction peaks of pure phase LaCrO3, indicating that LaCrO3 was successfully synthesized.

[0032] Fig.10 : The X-ray diffraction pattern of SmFeO3 shows that its diffraction peaks all correspond to the diffraction peaks of pure phase SmFeO3, indicating that SmFeO3 was successfully synthesized.

[0033] Fig.11 : The X-ray diffraction pattern of GdFeO3 shows that the diffraction peaks all correspond to the diffraction peaks of pure phase GdFeO3, indicating that GdFeO3 was successfully synthesized.

[0034] Fig.12 : The X-ray diffraction pattern of GdAlO3 shows that its diffraction peaks all correspond to the diffraction peaks of pure phase GdAlO3, indicating that GdAlO3 was successfully synthesized. DETAILED DESCRIPTION

[0035] The present invention is further described below by means of specific embodiments, but the protection scope of the present invention is not limited thereto.

[0036] In the following embodiments,

[0037] Joule heating equipment model: JH-3.3-P, Hefei In-situ Technology Co., Ltd., graphite groove size: 3cm*2cm*0.65cm;

[0038] The ammonium hydroxide solution was purchased from Sinopharm Chemical Reagent Co., Ltd., with a content of 25-28 wt % calculated as NH 3 .

[0039] Embodiment 1

[0040] The present embodiment provides a novel method for ultrafast and macro-scale synthesis of La2Zr2O7 based on Joule heat, comprising the following steps: 6.4984 g of lanthanum nitrate and 6.7852 g of zirconium nitrate are uniformly dispersed in 200 mL of deionized water, and an ammonium hydroxide solution is added dropwise under constant stirring until the pH value of the solution reaches 9, and then the addition is stopped, and then the solution is allowed to stand for 2 hours, the supernatant is poured out, and then the solution is centrifuged at 9500 rpm for 5 minutes to obtain a solid precursor;

[0041] The obtained solid precursor was transferred to a hot air drying oven at 80°C for drying for 24 hours;

[0042] The obtained solid precursor is added into the Joule heating graphite groove of the Joule heating device, the pulse discharge current is set to 400 amperes, the temperature is rapidly raised to 800°C in an air atmosphere, and then lowered to room temperature; the rapid heating-cooling cycle process is repeated 6 times to obtain La2Zr2O7 material.

[0043] Embodiment 2

[0044] The present embodiment provides a novel method for ultrafast and macro-scale synthesis of La2Ce2O7 based on Joule heat, comprising the following steps: 6.4984 g of lanthanum nitrate and 8.6844 g of cerium nitrate are uniformly dispersed in 200 mL of deionized water, and an ammonium hydroxide solution is added dropwise under constant stirring until the pH value of the solution reaches 9, and then the addition is stopped, and then the solution is allowed to stand for 2 hours, the supernatant is poured out, and then the solution is centrifuged at 9500 rpm for 5 minutes to obtain a solid precursor;

[0045] The obtained solid precursor was transferred to a hot air drying oven at 80°C for drying for 24 hours;

[0046] The obtained solid precursor is added into the Joule heating graphite groove of the Joule heating device, the pulse discharge current is set to 400 amperes, the temperature is rapidly raised to 800°C in an air atmosphere, and then lowered to room temperature; the rapid heating-cooling cycle process is repeated 6 times to obtain the La2Ce2O7 material.

[0047] Embodiment 3

[0048] The present embodiment provides a novel method for ultrafast and macro-scale synthesis of Y2Zr2O7 based on Joule heat, comprising the following steps: 5.4984 g of yttrium nitrate and 6.7852 g of zirconium nitrate are uniformly dispersed in 200 mL of deionized water, and an ammonium hydroxide solution is added dropwise under constant stirring until the pH value of the solution reaches 9, and then the addition is stopped, and then the solution is allowed to stand for 2 hours, the supernatant is poured out, and then the solution is centrifuged at 9500 rpm for 5 minutes to obtain a solid precursor;

[0049] The obtained solid precursor was transferred to a hot air drying oven at 80°C for drying for 24 hours;

[0050] The obtained solid precursor is added into the Joule heating graphite groove of the Joule heating device, the pulse discharge current is set to 400 amperes, the temperature is rapidly raised to 800°C in an air atmosphere, and then lowered to room temperature; the rapid heating-cooling cycle process is repeated 5 times to obtain the Y2Zr2O7 material.

[0051] Embodiment 4

[0052] The present embodiment provides a novel method for ultrafast and macro-scale synthesis of Ce2Zr2O7 based on Joule heat, comprising the following steps: 8.6844 g of cerium nitrate and 6.7852 g of zirconium nitrate are uniformly dispersed in 200 mL of deionized water, and an ammonium hydroxide solution is added dropwise under constant stirring until the pH value of the solution reaches 9, and then the addition is stopped, and then the solution is allowed to stand for 2 hours, the supernatant is poured out, and then centrifuged at 9500 rpm for 5 minutes to obtain a solid precursor;

[0053] The obtained solid precursor was transferred to a hot air drying oven at 80°C for drying for 24 hours;

[0054] The obtained solid precursor is added into the Joule heating graphite groove of the Joule heating device, the pulse discharge current is set to 400 amperes, the temperature is rapidly raised to 800°C in an air atmosphere, and then lowered to room temperature; the rapid heating-cooling cycle process is repeated 5 times to obtain the Ce2Zr2O7 material.

[0055] Embodiment 5

[0056] The present embodiment provides a novel method for ultrafast and macro-scale synthesis of Sm2Zr2O7 based on Joule heat, comprising the following steps: 6.7274 g of samarium nitrate and 6.7852 g of zirconium nitrate are uniformly dispersed in 200 mL of deionized water, and an ammonium hydroxide solution is added dropwise under constant stirring until the pH value of the solution reaches 9, and then the addition is stopped, and then the solution is allowed to stand for 2 hours, the supernatant is poured out, and then the solution is centrifuged at 9500 rpm for 5 minutes to obtain a solid precursor;

[0057] The obtained solid precursor was transferred to a hot air drying oven at 80°C for drying for 24 hours;

[0058] The obtained solid precursor is added into the Joule heating graphite groove of the Joule heating device, the pulse discharge current is set to 400 amperes, the temperature is rapidly raised to 800°C in an air atmosphere, and then lowered to room temperature; the rapid heating-cooling cycle process is repeated 5 times to obtain the Sm2Zr2O7 material.

[0059] Embodiment 6

[0060] The present embodiment provides a novel method for ultrafast and macro-scale synthesis of Gd2Zr2O7 based on Joule heat, comprising the following steps: 9.0272 g of gadolinium nitrate and 6.7852 g of zirconium nitrate are uniformly dispersed in 200 mL of deionized water, and an ammonium hydroxide solution is added dropwise under constant stirring until the pH value of the solution reaches 9, and then the addition is stopped, and then the solution is allowed to stand for 2 hours, the supernatant is poured out, and then the solution is centrifuged at 9500 rpm for 5 minutes to obtain a solid precursor;

[0061] The obtained solid precursor was transferred to a hot air drying oven at 80°C for drying for 24 hours;

[0062] The obtained solid precursor is added into the Joule heating graphite groove of the Joule heating device, the pulse discharge current is set to 400 amperes, the temperature is rapidly raised to 800°C in an air atmosphere, and then lowered to room temperature; the rapid heating-cooling cycle process is repeated 5 times to obtain the Gd2Zr2O7 material.

[0063] Embodiment 7

[0064] The present embodiment provides a novel method for ultrafast and macro-scale synthesis of LaAlO3 based on Joule heat, comprising the following steps: 6.4984 g of lanthanum nitrate and 4.2598 g of aluminum nitrate are uniformly dispersed in 200 mL of deionized water, and an ammonium hydroxide solution is added dropwise under constant stirring until the pH value of the solution reaches 9, and then the addition is stopped, and then the solution is allowed to stand for 2 hours, the supernatant is poured out, and then the solution is centrifuged at 9500 rpm for 5 minutes to obtain a solid precursor;

[0065] The obtained solid precursor was transferred to a hot air drying oven at 80°C for drying for 24 hours;

[0066] The obtained solid precursor is added into the Joule heating graphite groove of the Joule heating device, the pulse discharge current is set to 400 amperes, the temperature is rapidly raised to 800°C in an air atmosphere, and then lowered to room temperature; the rapid heating-cooling cycle process is repeated 6 times to obtain LaAlO3 material.

[0067] Embodiment 8

[0068] The present embodiment provides a new method for ultrafast and macro-scale synthesis of LaFeO3 based on Joule heat, comprising the following steps: 6.4984 g of lanthanum nitrate and 8.0798 g of ferric nitrate are uniformly dispersed in 200 mL of deionized water, and an ammonium hydroxide solution is added dropwise under constant stirring until the pH value of the solution reaches 8, and then the addition is stopped, and then the solution is allowed to stand for 2 hours, the supernatant is poured out, and then the solution is centrifuged at 9500 rpm for 5 minutes to obtain a solid precursor;

[0069] The obtained solid precursor was transferred to a hot air drying oven at 80°C for drying for 24 hours;

[0070] The obtained solid precursor is added into the Joule heating graphite groove of the Joule heating device, the pulse discharge current is set to 350 amperes, the temperature is rapidly raised to 700°C in an air atmosphere, and then lowered to room temperature; the rapid heating-cooling cycle process is repeated 5 times to obtain LaFeO3 material.

[0071] Embodiment 9

[0072] The present embodiment provides a novel method for ultrafast and macro-scale synthesis of LaCrO3 based on Joule heat, comprising the following steps: 6.4984 g of lanthanum nitrate and 8.0030 g of chromium nitrate are uniformly dispersed in 200 mL of deionized water, and an ammonium hydroxide solution is added dropwise under constant stirring until the pH value of the solution reaches 9, and then the addition is stopped, and then the solution is allowed to stand for 2 hours, the supernatant is poured out, and then the solution is centrifuged at 9500 rpm for 5 minutes to obtain a solid precursor;

[0073] The obtained solid precursor was transferred to a hot air drying oven at 80°C for drying for 24 hours;

[0074] The obtained solid precursor is added into the Joule heating graphite groove of the Joule heating device, the pulse discharge current is set to 400 amperes, the temperature is rapidly raised to 800°C in an air atmosphere, and then lowered to room temperature; the rapid heating-cooling cycle process is repeated 6 times to obtain the LaCrO3 material.

[0075] Embodiment 10

[0076] The present embodiment provides a novel method for ultrafast and macro-scale synthesis of SmFeO3 based on Joule heat, comprising the following steps: 6.7274 g of samarium nitrate and 8.0798 g of ferric nitrate are uniformly dispersed in 200 mL of deionized water, and an ammonium hydroxide solution is added dropwise under constant stirring until the pH value of the solution reaches 8, and then the addition is stopped, and then the solution is allowed to stand for 2 hours, the supernatant is poured out, and then the solution is centrifuged at 9500 rpm for 5 minutes to obtain a solid precursor;

[0077] The obtained solid precursor was transferred to a hot air drying oven at 80°C for drying for 24 hours;

[0078] The obtained solid precursor is added into the Joule heating graphite groove of the Joule heating device, the pulse discharge current is set to 350 amperes, the temperature is rapidly raised to 700°C in an air atmosphere, and then lowered to room temperature; the rapid heating-cooling cycle process is repeated 5 times to obtain the SmFeO3 material.

[0079] Embodiment 11

[0080] The present embodiment provides a novel method for ultrafast and macro-scale synthesis of GdFeO3 based on Joule heat, comprising the following steps: 9.0272 g of gadolinium nitrate and 8.0798 g of ferric nitrate are uniformly dispersed in 200 mL of deionized water, and an ammonium hydroxide solution is added dropwise under continuous stirring until the pH value of the solution reaches 8, and then the addition is stopped, and then the solution is allowed to stand for 2 hours, the supernatant is poured out, and then the solution is centrifuged at 9500 rpm for 5 minutes to obtain a solid precursor;

[0081] The obtained solid precursor was transferred to a hot air drying oven at 80°C for drying for 24 hours;

[0082] The obtained solid precursor is added into the Joule heating graphite groove of the Joule heating device, the pulse discharge current is set to 350 amperes, the temperature is rapidly raised to 700°C in an air atmosphere, and then lowered to room temperature; the rapid heating-cooling cycle process is repeated 5 times to obtain the GdFeO3 material.

[0083] Embodiment 12

[0084] This embodiment provides a new method for ultrafast and macro-scale synthesis of GdAlO3 based on Joule heat, comprising the following steps: 9.0272 g of gadolinium nitrate and 4.2598 g of aluminum nitrate are uniformly dispersed in 200 mL of deionized water, and an ammonium hydroxide solution is added dropwise under constant stirring until the pH value of the solution reaches 9, and then the addition is stopped, and then the solution is allowed to stand for 2 hours, the supernatant is poured out, and then centrifuged at 9500 rpm for 5 minutes to obtain a solid precursor;

[0085] The obtained solid precursor was transferred to a hot air drying oven at 80°C for drying for 24 hours;

[0086] The obtained solid precursor is added into the Joule heating graphite groove of the Joule heating device, the pulse discharge current is set to 400 amperes, the temperature is rapidly raised to 800°C in an air atmosphere, and then lowered to room temperature; the rapid heating-cooling cycle process is repeated 6 times to obtain the GdAlO3 material.

Claims

1. A method for ultrafast synthesis of pyrochlore-type and perovskite-type oxides based on Joule heat, characterized in that: The method comprises: The metal source A and the metal source B are uniformly dispersed in deionized water to obtain a metal source solution, and an ammonium hydroxide solution is added dropwise to a pH of 9 under stirring, and the solution is allowed to stand, and the supernatant is poured out and centrifuged to obtain a solid precursor; the obtained solid precursor is dried, placed in a Joule heat device, and heated to 700-800° C. by pulse discharge to generate Joule heat in an air atmosphere, and then cooled to room temperature, and the heating-cooling operation is repeated several times to obtain a target product; The metal elements in the metal source A and the metal source B are selected from at least two of lanthanum, zirconium, cerium, yttrium, samarium, gadolinium, aluminum, iron, and chromium.

2. The method for ultrafast synthesis of pyrochlore-type and perovskite-type oxides based on Joule heat as claimed in claim 1, characterized in that: The metal source A and the metal source B are in the form of metal nitrates, metal chlorides, metal oxides, or metal stannates.

3. The method for ultrafast synthesis of pyrochlore-type and perovskite-type oxides based on Joule heat as claimed in claim 1, characterized in that: The molar ratio of metal source A to metal source B is 1 to 2:

1.

4. The method for ultrafast synthesis of pyrochlore-type and perovskite-type oxides based on Joule heat as claimed in claim 1, characterized in that: The total feed ratio of deionized water to metal source A and metal source B is 200:10-20, mL / g.

5. The method for ultrafast synthesis of pyrochlore-type and perovskite-type oxides based on Joule heat as claimed in claim 1, characterized in that: When the metal source A is selected from lanthanum nitrate, yttrium nitrate, cerium nitrate, samarium nitrate or gadolinium nitrate, the metal source B is selected from zirconium nitrate or cerium nitrate, and the metal source A is different from the metal source B, the target product obtained is a pyrochlore-type oxide; when the metal source A is selected from lanthanum nitrate, samarium nitrate or gadolinium nitrate, the metal source B is selected from aluminum nitrate, iron nitrate or chromium nitrate, the target product obtained is a perovskite-type oxide.

6. The method for ultrafast synthesis of pyrochlore-type and perovskite-type oxides based on Joule heat as claimed in claim 1, characterized in that: The heating-cooling operation is cycled 5 to 8 times.

7. The method for ultrafast synthesis of pyrochlore-type and perovskite-type oxides based on Joule heat as claimed in claim 1, characterized in that: The current of pulse discharge is 300-400 amperes, the single discharge time of pulse discharge is 5-8s, and the maximum temperature generated by Joule heat is 700-800°C; the power supply used for pulse discharge is DC power supply or AC power supply.

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