Gadolinium-doped ceria nanopowder flame synthesis apparatus and synthesis method

Abstract

The application discloses a kind of gadolinium-doped ceria nanopowder flame synthesis device and synthesis method, it is related to nanometer powder material preparation technical field, gadolinium-doped ceria nanopowder flame synthesis device includes: synthesis device main body, synthesis chamber is in synthesis device main body, synthesis device main body is equipped with with synthesis chamber communication's discharge port;Bottom burner, bottom burner is equipped in the bottom of synthesis device main body, bottom burner is communicated with gas source, air source and first precursor source;Multiple rotary cutting burners, multiple rotary cutting burners are spaced apart along the circumference of synthesis device main body, each rotary cutting burner is communicated with gas source, air source and second precursor source, the axial direction of each rotary cutting burner is tangent to the projection of bottom burner perpendicular to the axial direction of bottom burner.According to the gadolinium-doped ceria nanopowder flame synthesis device of embodiment of the application has the advantages such as high synthesis efficiency, good synthesis uniformity.

Description

Technical Field

[0001] This invention relates to the field of nanopowder material preparation technology, and more specifically, to a flame synthesis apparatus and method for gadolinium-doped cerium oxide nanopowder. Background Technology

[0002] Gadolinium-doped cerium oxide nanoceramics (GDC, chemical formula Gd) x Ce 1- x O 2-0.5x (where 0.1≤x≤0.2) is an advanced ceramic powder obtained by "modifying" cerium oxide through doping. Gadolinium-doped cerium oxide nanoceramics are key materials in low- and medium-temperature solid oxide fuel cells. They exhibit superior ionic conductivity compared to traditional materials at low and medium temperatures, reducing battery operating temperature, improving stability and lifespan. Simultaneously, they prevent chemical reactions between high-performance cathode materials and the electrolyte, thus preventing the formation of insulating impurities and significantly enhancing battery output performance. GDC materials can also be applied in catalysis, sensors, and other fields. In terms of material properties, gadolinium-doped cerium oxide nanoparticles can form oxygen ion channels, making them an ideal choice for low- and medium-temperature solid oxide fuel cells. Their performance is highly dependent on the doping amount, powder purity, particle morphology, and sintering density.

[0003] Methods for synthesizing gadolinium-doped cerium oxide nanoceramics include co-precipitation, sol-gel, combustion synthesis, and hydrothermal methods. Among these, flame synthesis utilizes the exothermic reaction of metal nitrates with organic fuels to instantaneously synthesize nanopowder materials. It offers advantages such as rapid one-step synthesis, energy saving, large specific surface area of ​​the product, and high activity of the synthesized powder, making it particularly advantageous for synthesizing high-performance gadolinium-doped cerium oxide nanopowder materials.

[0004] The flame synthesis device for gadolinium-doped cerium oxide nanopowder in related technologies has poor doping uniformity and low yield. Summary of the Invention

[0005] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, the present invention proposes a flame synthesis apparatus for gadolinium-doped cerium oxide nanopowder, which has the advantages of high synthesis efficiency and good synthesis uniformity.

[0006] This invention also proposes a synthesis method with a flame synthesis apparatus for gadolinium-doped cerium oxide nanopowder.

[0007] To achieve the above objectives, an embodiment of the present invention provides a flame synthesis apparatus for gadolinium-doped cerium oxide nanopowder. The flame synthesis apparatus for gadolinium-doped cerium oxide nanopowder includes: a synthesis apparatus body having a synthesis chamber, and an exhaust port communicating with the synthesis chamber; a bottom burner located at the bottom of the synthesis apparatus body and communicating with a gas source, an air source, and a first precursor source; and a plurality of rotary burners spaced apart circumferentially along the synthesis apparatus body, each rotary burner communicating with a gas source, an air source, and a second precursor source, wherein the axial direction of each rotary burner is tangent to the projection of the bottom burner perpendicular to the axial direction of the bottom burner.

[0008] The flame synthesis apparatus for gadolinium-doped cerium oxide nanopowder according to embodiments of the present invention has advantages such as high synthesis efficiency and good synthesis uniformity.

[0009] In addition, the flame synthesis apparatus for gadolinium-doped cerium oxide nanopowder according to the above embodiments of the present invention may also have the following additional technical features: According to one embodiment of the present invention, the rotary burner includes: a second precursor atomizer, the second precursor atomizer being connected to a second precursor source; an arc-shaped gas nozzle, the arc-shaped gas nozzle being connected to the gas source, the arc-shaped gas nozzle being arc-shaped and coaxially arranged with the second precursor atomizer, the arc-shaped gas nozzle being located radially outside the second precursor atomizer; and an arc-shaped air nozzle, the arc-shaped air nozzle being connected to the air source, the arc-shaped air nozzle being arc-shaped and coaxially arranged with the second precursor atomizer, the arc-shaped air nozzle being located radially outside the arc-shaped gas nozzle, and the arc-shaped gas nozzle and the arc-shaped air nozzle being located on the same side of the circumference of the second precursor atomizer.

[0010] According to one embodiment of the present invention, the bottom burner includes: a first precursor atomizer, the first precursor atomizer being in communication with a first precursor source; and a swirling flame generator, the swirling flame generator being coaxially arranged with the first precursor atomizer and located radially outside the first precursor atomizer, the swirling flame generator being in communication with the air source and the gas source, and the swirling flame generator being adapted to mix air and gas and form a swirling flame after ignition.

[0011] According to one embodiment of the present invention, the main body of the synthesis apparatus includes: an outlet section, wherein the discharge port is formed at the upper end of the outlet section, and the inner diameter of the outlet section gradually increases from top to bottom; a secondary synthesis chamber, wherein the upper end of the secondary synthesis chamber is connected to the lower end of the outlet section; a transition section, wherein the upper end of the transition section is connected to the lower end of the secondary synthesis chamber, and the inner diameter of the transition section gradually decreases from top to bottom; a primary synthesis chamber, wherein the upper end of the primary synthesis chamber is connected to the lower end of the transition section; and a bottom conical section, wherein the upper end of the bottom conical section is connected to the lower end of the primary synthesis chamber, and the inner diameter of the bottom conical section gradually decreases from top to bottom, and a bottom burner is disposed at the lower end of the bottom conical section.

[0012] According to one embodiment of the present invention, the discharge port, the outlet section, the secondary synthesis chamber, the transition section, the primary synthesis chamber, the bottom conical section, and the bottom burner are coaxially arranged.

[0013] According to one embodiment of the present invention, the first precursor source is a first precursor storage tank, which is adapted to store the first precursor; the second precursor source is a second precursor storage tank, which is adapted to store the second precursor; the air source is an air storage tank; and the gas source is a gas storage tank.

[0014] According to one embodiment of the present invention, a first liquid flow pump is connected between the first precursor tank and the bottom burner, and a second liquid flow pump is connected between the second precursor tank and the rotary burner.

[0015] According to one embodiment of the present invention, a flow regulating valve is provided between the first precursor storage tank and the bottom burner, between the second precursor storage tank and the rotary burner, between the air storage tank and the bottom burner, between the air storage tank and the rotary burner, between the gas storage tank and the bottom burner, and between the gas storage tank and the rotary burner.

[0016] According to a second aspect of the present invention, a method for flame synthesis of gadolinium-doped cerium oxide nanopowder is provided. The method employs the gadolinium-doped cerium oxide nanopowder flame synthesis apparatus described in the first aspect of the present invention, and includes the following steps: The air source and the gas source are turned on, the gas-air mixture is ignited, a preheating flame is formed at the outlet of the bottom burner, and a swirl burner forms a swirl flame above the bottom burner; The supply of the first precursor source and the second precursor source is turned on, and the first precursor and the second precursor are delivered to the bottom burner and the plurality of the rotary burners, so that the first precursor and the second precursor are broken into droplets and sprayed into the synthesis chamber. The droplets enter the synthesis chamber and undergo evaporation, combustion, thermal decomposition of metal salts, crystal nucleation and growth processes to transform into gadolinium-doped cerium oxide nanopowder materials, which are then discharged through the discharge port.

[0017] The flame synthesis method for gadolinium-doped cerium oxide nanopowder according to embodiments of the present invention, by utilizing the flame synthesis apparatus for gadolinium-doped cerium oxide nanopowder according to the first aspect of the present invention, has advantages such as high synthesis efficiency and good synthesis uniformity.

[0018] According to one embodiment of the present invention, the first precursor is a cerium nitrate solution or a mixed precursor solution, and the second precursor is a gadolinium nitrate solution or a mixed precursor solution. The method for preparing the mixed precursor solution includes the following steps: Gadolinium nitrate and isooctanoic acid were mixed and stirred to carry out a pre-complexation reaction until a gadolinium complex solution was formed; Dissolve the measured amount of cerium nitrate in anhydrous ethanol and stir until completely dissolved to form a cerium nitrate ethanol solution; The gadolinium complex solution was added dropwise to the cerium nitrate ethanol solution under continuous shearing and stirring. After the addition is complete, add isooctanoic acid to the mixture to bring the solution to the predetermined ratio, and stir. Acetic acid or butyric acid is added and mixed online, and the pH is measured until a predetermined pH is reached to form the mixed precursor solution.

[0019] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0020] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a schematic diagram of the structure of a flame synthesis apparatus for gadolinium-doped cerium oxide nanopowder according to an embodiment of the present invention.

[0021] Figure 2 This is a partial cross-sectional view of a flame synthesis apparatus for gadolinium-doped cerium oxide nanopowder according to an embodiment of the present invention.

[0022] Figure 3 This is a partial cross-sectional view of a flame synthesis apparatus for gadolinium-doped cerium oxide nanopowder according to an embodiment of the present invention.

[0023] Figure 4 This is a schematic diagram of the rotary burner of the flame synthesis apparatus for gadolinium-doped cerium oxide nanopowder according to an embodiment of the present invention.

[0024] Figure 5 This is a schematic diagram of the rotary burner of the flame synthesis apparatus for gadolinium-doped cerium oxide nanopowder according to an embodiment of the present invention.

[0025] Figure 6 This is a flowchart of a flame synthesis method for gadolinium-doped cerium oxide nanopowder according to an embodiment of the present invention.

[0026] Figure 7 This is a flowchart of a method for preparing a mixed precursor solution for flame synthesis of gadolinium-doped cerium oxide nanopowder according to an embodiment of the present invention.

[0027] Figure 8 This is a microscopic schematic diagram of gadolinium-doped cerium oxide nanopowder prepared by the flame synthesis method of gadolinium-doped cerium oxide nanopowder according to an embodiment of the present invention.

[0028] Figure 9 This is a microstructure of gadolinium-doped cerium oxide nanopowder prepared by the flame synthesis method of gadolinium-doped cerium oxide nanopowder according to an embodiment of the present invention.

[0029] Reference numerals in the attached figures: 1. Flame synthesis apparatus for gadolinium-doped cerium oxide nanopowder; 10. Main body of the synthesis apparatus; 11. Discharge port; 12. Outlet section; 13. Secondary synthesis chamber; 14. Transition section; 15. Primary synthesis chamber; 16. Bottom conical section; 20. Bottom burner; 21. First precursor atomizer; 22. Swirl flame generator; 30. Rotary cutter burner; 31. Second precursor atomizer; 32. Arc-shaped gas nozzle; 33. Arc-shaped air nozzle; 40. First precursor storage tank; 50. Second precursor storage tank; 60. Air storage tank; 70. Gas storage tank; 81. First liquid pump; 82. Second liquid pump; 90. Flow regulating valve. Detailed Implementation

[0030] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0031] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, features defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more. In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0032] The following description, with reference to the accompanying drawings, describes a flame synthesis apparatus 1 for gadolinium-doped cerium oxide nanopowder according to an embodiment of the present invention.

[0033] like Figures 1-9 As shown, the flame synthesis apparatus 1 for gadolinium-doped cerium oxide nanopowder according to an embodiment of the present invention includes a synthesis apparatus body 10, a bottom burner 20 and a plurality of rotary burners 30 (the up and down direction is shown by the arrows in the figure).

[0034] The synthesis apparatus body 10 has a synthesis chamber, and the synthesis apparatus body 10 is provided with an exhaust port 11 communicating with the synthesis chamber. A bottom burner 20 is located at the bottom of the synthesis apparatus body 10, and the bottom burner 20 is connected to a gas source, an air source, and a first precursor source. Multiple rotary burners 30 are spaced apart circumferentially along the synthesis apparatus body 10. Each rotary burner 30 is connected to a gas source, an air source, and a second precursor source, and the axial direction of each rotary burner 30 is tangent to the projection of the bottom burner 20 perpendicular to its axial direction.

[0035] Specifically, firstly, the air and gas sources are turned on. Air and gas enter the synthesis chamber through the bottom burner 20 and multiple rotary burners 30. The gas-air mixture is ignited within the synthesis chamber, forming a preheated flame at the outlet of the bottom burner 20. The rotary burners 30 form a rotary flame above the bottom burner 20. Next, the first and second precursor sources are turned on, delivering the first and second precursors to the bottom burner 20 and multiple rotary burners 30. This causes the first and second precursors to break into droplets and spray into the synthesis chamber. The droplets enter the synthesis chamber and undergo evaporation, combustion, thermal decomposition of the metal salt, crystallization nucleation, and growth processes, transforming into gadolinium-doped cerium oxide nanoparticles, which are then discharged through the exhaust port 11. The gadolinium-doped cerium oxide nanoparticles discharged through exhaust port 11 are then collected in a subsequent collection process.

[0036] like Figure 2 and Figure 3 As shown, the jet direction of the gas flow ejected by each rotary burner 30 is tangent to the projection of the bottom burner 20 in the vertical direction. In other words, the projection of the bottom burner 20 in the horizontal plane is circular, and the axial direction of the rotary burner 30 is tangent to this circle. Thus, after the multiple jets from the multiple rotary burners 30 are injected, a high-speed rotating flame flow is formed at the bottom of the synthesis chamber, promoting the uniform and rapid mixing of the second precursor with the central flame ejected from the bottom burner 20.

[0037] According to an embodiment of the present invention, the flame synthesis apparatus 1 for gadolinium-doped cerium oxide nanopowder is provided with a bottom burner 20 and a rotary burner 30, which allows air, fuel gas and precursor to be injected into the synthesis chamber and ignited together. This allows for the synthesis of gadolinium-doped cerium oxide nanopowder by flame synthesis, giving full play to the advantages of flame synthesis method, which is rapid and instantaneous nucleation in one step. The process is simple, energy consumption is low, the powder synthesis cycle is significantly shortened, production efficiency is improved, and it is beneficial to increase output.

[0038] Furthermore, by setting multiple rotary burners 30, with the axial direction of each rotary burner 30 tangent to the projection of the bottom burner 20 perpendicular to its axial direction, multiple jets from the rotary burners 30 can be injected into the synthesis chamber, forming a high-speed rotating flame stream at the bottom of the synthesis chamber. The second precursor ejected from the rotary burners 30 mixes rapidly and thoroughly with the central flame stream formed by the bottom burner 20, ensuring thorough mixing of the first precursor, the second precursor, and the flame. This promotes the mixing of the first and second precursors, improves the mixing uniformity, and enhances the heating uniformity of the precursors, thereby improving the uniformity and synthesis quality of the synthesized gadolinium-doped cerium oxide nanopowder.

[0039] Therefore, the flame synthesis apparatus 1 for gadolinium-doped cerium oxide nanopowder according to the present invention has the advantages of high synthesis efficiency and good synthesis uniformity.

[0040] The following description, with reference to the accompanying drawings, describes a flame synthesis apparatus 1 for gadolinium-doped cerium oxide nanopowder according to a specific embodiment of the present invention.

[0041] In some specific embodiments of the present invention, such as Figures 1-9 As shown, the flame synthesis apparatus 1 for gadolinium-doped cerium oxide nanopowder according to an embodiment of the present invention includes a synthesis apparatus body 10, a bottom burner 20, and a plurality of rotary burners 30.

[0042] Specifically, such as Figure 4 and Figure 5 As shown, the rotary burner 30 includes a second precursor atomizer 31, an arc-shaped gas nozzle 32, and an arc-shaped air nozzle 33. The second precursor atomizer 31 is connected to the second precursor source. The arc-shaped gas nozzle 32 is connected to the gas source, and is arc-shaped and coaxially arranged with the second precursor atomizer 31, located radially outside the second precursor atomizer 31. The arc-shaped air nozzle 33 is connected to the air source, and is arc-shaped and coaxially arranged with the second precursor atomizer 31, located radially outside the arc-shaped gas nozzle 32. The arc-shaped gas nozzle 32 and the arc-shaped air nozzle 33 are located on the same side of the circumference of the second precursor atomizer 31. Specifically, multiple rotary burners 30 are rotationally symmetrical about the central axis of the synthesis device body 10. In other words, multiple arc-shaped gas nozzles 32 and multiple arc-shaped air nozzles 33 are located on the same side of the second precursor atomizer 31 in the circumferential direction of the synthesis device body 10. The cross-section of the arc-shaped gas nozzles 32 and arc-shaped air nozzles 33 perpendicular to the axial direction can be semi-circular. The second precursor atomizer 31 is suitable for atomizing the precursor. Multiple rotary burners 30 can be equally spaced in the circumferential direction of the synthesis device body 10. There can be three rotary burners 30. In this way, a high-momentum air jet can be formed by the arc-shaped air nozzles 33, which mixes with the gas flow ejected from the arc-shaped gas nozzles 32, and then further mixes with the atomized jet of the second precursor atomizer 31. The three form a step-by-step injection mixing effect, ensuring the formation of a high-temperature flame and a large jet depth, which facilitates the cooperation of multiple rotary burners 30 to form a high-speed rotating flame flow.

[0043] More specifically, such as Figure 1 and Figure 2As shown, the bottom burner 20 includes a first precursor atomizer 21 and a swirling flame generator 22. The first precursor atomizer 21 is connected to the first precursor source. The swirling flame generator 22 is coaxially arranged with the first precursor atomizer 21 and located radially outside the first precursor atomizer 21. The swirling flame generator 22 is connected to the air source and the fuel source, and is adapted to mix air and fuel gas to form a swirling flame after ignition. Specifically, the first precursor atomizer 21 is adapted to atomize the precursor. The swirling flame generator 22 may have spiral blades to facilitate the mixing of air and fuel gas and its ejection in a spiral flow, thus facilitating the formation of a swirling flame. This facilitates the formation of a swirling flame by the bottom burner 20.

[0044] Thus, the bottom burner 20 can form an atomized synthesis flame at the bottom of the synthesis chamber, forming primary nanoparticles at the bottom of the synthesis chamber. Then, when flowing through the rotary burner 30, they are further uniformly and rapidly doped to form gadolinium-doped cerium oxide nanoparticles.

[0045] Advantageously, such as Figure 1 and Figure 2 As shown, the main body 10 of the synthesis apparatus includes an outlet section 12, a secondary synthesis chamber 13, a transition section 14, a primary synthesis chamber 15, and a bottom conical section 16. An outlet 11 is formed at the upper end of the outlet section 12, and the inner diameter of the outlet section 12 gradually increases from top to bottom. The upper end of the secondary synthesis chamber 13 is connected to the lower end of the outlet section 12. The upper end of the transition section 14 is connected to the lower end of the secondary synthesis chamber 13, and the inner diameter of the transition section 14 gradually decreases from top to bottom. The upper end of the primary synthesis chamber 15 is connected to the lower end of the transition section 14. The upper end of the bottom conical section 16 is connected to the lower end of the primary synthesis chamber 15, and the inner diameter of the bottom conical section 16 gradually decreases from top to bottom. A bottom burner 20 is located at the lower end of the bottom conical section 16. Specifically, the inner diameter of the primary synthesis chamber 15 is 0.6-0.8 times the inner diameter of the secondary synthesis chamber 13. This facilitates the formation of the synthesis chamber, allowing the precursor to be gradually synthesized within the chamber and ultimately discharged through the discharge port 11.

[0046] More advantageously, such as Figure 1 and Figure 2 As shown, the exhaust port 11, outlet section 12, secondary synthesis chamber 13, transition section 14, primary synthesis chamber 15, bottom conical section 16, and bottom burner 20 are coaxially arranged. Specifically, the exhaust port 11, outlet section 12, secondary synthesis chamber 13, transition section 14, primary synthesis chamber 15, bottom conical section 16, and bottom burner 20 are all rotationally symmetrical structures, for example, they can all be circular. This can further improve the uniformity of flame and precursor mixing.

[0047] Figure 1An apparatus 1 for flame synthesis of gadolinium-doped cerium oxide nanopowder according to some examples of the present invention is shown. Figure 1 As shown, the first precursor source is a first precursor storage tank 40, which is suitable for storing the first precursor. The second precursor source is a second precursor storage tank 50, which is suitable for storing the second precursor. The air source is an air storage tank 60, and the gas source is a gas storage tank 70. Specifically, the first precursor storage tank 40 and the bottom burner 20, the second precursor storage tank 50 and the rotary burner 30, the air storage tank 60 and the bottom burner 20, the air storage tank 60 and the rotary burner 30, the gas storage tank 70 and the bottom burner 20, and the gas storage tank 70 and the rotary burner 30 can be connected by pipelines. The pipelines can have multiple branches to facilitate the connection of multiple rotary burners 30. This facilitates the storage of precursors, gas, and air, and facilitates the control of the synthesis process.

[0048] Advantageously, such as Figure 1 As shown, a first liquid flow pump 81 is connected between the first precursor tank 40 and the bottom burner 20, and a second liquid flow pump 82 is connected between the second precursor tank 50 and the rotary burner 30. This allows the liquid flow pumps to provide sufficient driving force for the atomization and injection of the precursor, ensuring atomization effect.

[0049] More advantageously, such as Figure 1 As shown, flow regulating valves 90 are provided between the first precursor storage tank 40 and the bottom burner 20, between the second precursor storage tank 50 and the rotary burner 30, between the air storage tank 60 and the bottom burner 20, between the air storage tank 60 and the rotary burner 30, between the gas storage tank 70 and the bottom burner 20, and between the gas storage tank 70 and the rotary burner 30. This facilitates the adjustment of the flow rates of the precursor, air, and gas, thereby facilitating the control and regulation of the synthesis process.

[0050] Therefore, it is convenient to achieve precise control over the particle size, morphology and doping uniformity of the powder, thereby facilitating the preparation of high-performance gadolinium-doped cerium oxide nanopowders with high phase purity, small particle size, large specific surface area and high sintering activity. The following describes a flame synthesis method for gadolinium-doped cerium oxide nanopowder according to an embodiment of the present invention. The flame synthesis method for gadolinium-doped cerium oxide nanopowder according to an embodiment of the present invention employs the gadolinium-doped cerium oxide nanopowder flame synthesis apparatus 1 according to the above embodiment of the present invention, and includes the following steps: The air source and the gas source are turned on, the gas and air mixture is ignited, a preheated flame is formed at the outlet of the bottom burner 20, and a swirl burner 30 forms a swirl flame above the bottom burner 20; Turn on the supply of the first precursor source and the second precursor source, and deliver the first precursor and the second precursor to the bottom burner 20 and multiple rotary burners 30, so that the first precursor and the second precursor are broken into droplets and sprayed into the synthesis chamber. The droplets enter the synthesis chamber and undergo evaporation, combustion, thermal decomposition of metal salts, crystal nucleation and growth processes to transform into gadolinium-doped cerium oxide nanopowder materials, which are then discharged through the discharge port 11.

[0051] Specifically, the gaseous fuel can be methane.

[0052] The flame synthesis method for gadolinium-doped cerium oxide nanopowder according to the embodiments of the present invention has the advantages of high synthesis efficiency and good synthesis uniformity by utilizing the flame synthesis apparatus 1 for gadolinium-doped cerium oxide nanopowder according to the above embodiments of the present invention.

[0053] The following describes a flame synthesis method for gadolinium-doped cerium oxide nanopowder according to some specific embodiments of the present invention.

[0054] Turn on the air and methane gas supply, setting the initial air flow rate to 35-45 L / min and the methane flow rate to 1.8-2.2 L / min. Ignite the methane-air mixture using an ignition device, forming a stable and highly uniform annular preheating flame around the outlet of the bottom burner 20, with the flame height consistently within the range of 50-70 cm. Simultaneously, the rotary burner 30 forms a high-speed rotary flame above the bottom burner 20, providing a continuous and uniform high-temperature environment for subsequent synthesis. Start the first precursor atomizer 21 and the second precursor atomizer 31 to inject the precursor solution into the first precursor storage tank 40 and the second precursor storage tank 50. Start the first liquid flow pump 81 and the second liquid flow pump 82 to deliver the precursor solution to the first precursor atomizer 21 and the second precursor atomizer 31 at a stable flow rate of 5-8L / h. The solution is efficiently broken into micron-sized droplets and sprayed into the core of the high-temperature reaction zone at high speed. After the precursor droplets enter the high-temperature reaction zone above 1400℃, they undergo millisecond-level rapid evaporation, combustion, thermal decomposition of metal salts, and final crystallization nucleation and growth processes, transforming into gadolinium-doped cerium oxide nanopowder materials in one step. The gadolinium-doped cerium oxide nanoparticles synthesized by flame are discharged through outlet 11 and enter the subsequent powder collection process to collect the nanoparticles.

[0055] Specifically, such as Figure 7 As shown, the first precursor is a cerium nitrate solution or a mixed precursor solution, and the second precursor is a gadolinium nitrate solution or a mixed precursor solution. The preparation method of the mixed precursor solution includes the following steps: Gadolinium nitrate and isooctanoic acid were mixed and stirred to carry out a pre-complexation reaction until a gadolinium complex solution was formed; Dissolve the measured amount of cerium nitrate in anhydrous ethanol and stir until completely dissolved to form a cerium nitrate ethanol solution; The gadolinium complex solution was added dropwise to the cerium nitrate ethanol solution under continuous shearing and stirring. After the addition is complete, add isooctanoic acid to the mixture to bring the solution to the predetermined ratio, and stir. Acetic acid or butyric acid is added and mixed online, and the pH is measured until a predetermined pH is reached to form the mixed precursor solution.

[0056] This facilitates the formation of mixed precursor solutions, achieving uniform distribution of gadolinium cerium ions at the molecular level, and further improving the uniformity of synthesis doping.

[0057] The following describes a method for preparing the mixed precursor solution according to some examples of the present invention.

[0058] Cerium nitrate (Ce(NO3)3·6H2O) and gadolinium nitrate (Gd(NO3)3·6H2O) were used as metal sources, both with a purity of not less than 99.9%. The solvent system consisted of isooctanoic acid (EHA) as the main solvent and anhydrous ethanol as the co-solvent, both with a purity higher than 99.5%; at the same time, a small amount of acetic acid (or butyric acid) was added to adjust the pH value of the solution. The measured gadolinium nitrate and isooctanoic acid, accounting for 20%-30% of the total isooctanoic acid, are placed in a mixing container and subjected to a pre-complexation reaction at 40℃-50℃ and low-speed stirring (100-200rpm) for 20-30 minutes until a homogeneous and transparent gadolinium complex solution is formed. In another container, the measured amount of cerium nitrate is dissolved in a portion of anhydrous ethanol and stirred at room temperature until completely dissolved to form a clear cerium nitrate ethanol solution. The gadolinium complex solution obtained in the above steps is slowly added dropwise to the cerium nitrate ethanol solution prepared in the above steps under continuous high-speed shear (400-600 rpm). After the addition is complete, continue mixing under high-speed shear for 15-20 minutes to ensure that gadolinium and cerium ions achieve a preliminary uniform distribution at the molecular level in the solution. Add the remaining isooctanoic acid to the above mixture to make the solvent system complete. Continue stirring for 10-15 minutes, then add acetic acid (or butyric acid) for online mixing and measure the pH until the pH reaches 4-5 to form the final homogeneous precursor solution. The solution temperature was controlled between 22℃ and 33℃ to stabilize its dynamic viscosity at 6.0-8.5 mPa·s; The obtained GDC precursor solution should be a colorless to pale yellow transparent liquid with no visible precipitation or phase separation. Its density is about 1.05-1.15 g / cm³, and it has good stability, and can be stored for no less than 48 hours without any change in properties. Therefore, by establishing standardized precursor formulations, the problem of batch-to-batch performance fluctuations in flame synthesis in related technologies has been effectively solved, achieving high repeatability and stability of powder chemical composition and physical properties, and ensuring the reliability of subsequent device performance.

[0059] Microscopic illustration of the synthesized gadolinium-doped cerium oxide nanoparticles is shown below. Figure 8 As shown, the microscopic element distribution diagram is as follows: Figure 9 As shown, it exhibits good uniformity.

[0060] Gadolinium-doped cerium oxide nanopowder, synthesized by the flame synthesis method according to an embodiment of the present invention, was pressed into discs with a diameter of 20 mm and a thickness of approximately 0.8 mm using a tablet press. These discs were then sintered at 1500 °C for 1 hour to obtain test samples. Silver paste was applied to the upper and lower surfaces of the test samples using screen printing. The samples were connected to an electrochemical workstation via silver wires, and data was collected after heating to the test temperature in a tube furnace.

[0061] The above electrolyte samples were subjected to AC impedance spectroscopy tests at frequencies ranging from 0.1 to 106 Hz and temperatures ranging from 600 to 800 °C. The results are shown in the table below. It can be seen that the gadolinium-doped cerium oxide material synthesized using this invention has a significantly higher overall conductivity than yttrium-stabilized zirconia powder material, demonstrating excellent material properties.

[0062]

[0063] Other components and operations of the flame synthesis apparatus 1 for gadolinium-doped cerium oxide nanopowder according to embodiments of the present invention are known to those skilled in the art and will not be described in detail here.

[0064] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0065] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A flame synthesis apparatus for gadolinium-doped cerium oxide nanopowder, characterized in that, include: The main body of the synthesis device has a synthesis chamber inside, and the main body of the synthesis device is provided with a discharge port communicating with the synthesis chamber; A bottom burner is provided at the bottom of the main body of the synthesis device and is connected to a gas source, an air source and a first precursor source. Multiple rotary burners are arranged circumferentially along the main body of the synthesis device. Each rotary burner is connected to a gas source, an air source, and a second precursor source. The axial direction of each rotary burner is tangent to the projection of the bottom burner perpendicular to the axial direction of the bottom burner.

2. The flame synthesis apparatus for gadolinium-doped cerium oxide nanopowder according to claim 1, characterized in that, The rotary burner includes: The second precursor atomizer is connected to the second precursor source; An arc-shaped gas nozzle is connected to the gas source. The arc-shaped gas nozzle is arc-shaped and coaxially arranged with the second precursor atomizer. The arc-shaped gas nozzle is located on the radial outer side of the second precursor atomizer. An arc-shaped air nozzle is connected to the air source. The arc-shaped air nozzle is arc-shaped and coaxially arranged with the second precursor atomizer. The arc-shaped air nozzle is located radially outside the arc-shaped gas nozzle. The arc-shaped gas nozzle and the arc-shaped air nozzle are located on the same side of the circumference of the second precursor atomizer.

3. The flame synthesis apparatus for gadolinium-doped cerium oxide nanopowder according to claim 1, characterized in that, The bottom burner includes: The first precursor atomizer is connected to the first precursor source; A swirling flame generator is coaxially arranged with the first precursor atomizer and located radially outside the first precursor atomizer. The swirling flame generator is connected to the air source and the gas source. The swirling flame generator is adapted to mix air and gas and form a swirling flame after ignition.

4. The flame synthesis apparatus for gadolinium-doped cerium oxide nanopowder according to claim 1, characterized in that, The main body of the synthesis apparatus includes: The outlet section has an outlet formed at its upper end, and the inner diameter of the outlet section gradually increases from top to bottom. A secondary synthesis chamber, the upper end of which is connected to the lower end of the outlet section; A transition section, the upper end of which is connected to the lower end of the secondary synthesis cavity, wherein the inner diameter of the transition section gradually decreases from top to bottom; A primary synthesis cavity, the upper end of which is connected to the lower end of the transition section; The bottom conical section has its upper end connected to the lower end of the primary synthesis chamber. The inner diameter of the bottom conical section gradually decreases from top to bottom, and the bottom burner is located at the lower end of the bottom conical section.

5. The flame synthesis apparatus for gadolinium-doped cerium oxide nanopowder according to claim 4, characterized in that, The discharge port, the outlet section, the secondary synthesis chamber, the transition section, the primary synthesis chamber, the bottom conical section, and the bottom burner are coaxially arranged.

6. The flame synthesis apparatus for gadolinium-doped cerium oxide nanopowder according to claim 1, characterized in that, The first precursor source is a first precursor storage tank, which is suitable for storing the first precursor. The second precursor source is a second precursor storage tank, which is suitable for storing the second precursor. The air source is an air storage tank, and the gas source is a gas storage tank.

7. The flame synthesis apparatus for gadolinium-doped cerium oxide nanopowder according to claim 6, characterized in that, A first liquid flow pump is connected between the first precursor tank and the bottom burner, and a second liquid flow pump is connected between the second precursor tank and the rotary burner.

8. The flame synthesis apparatus for gadolinium-doped cerium oxide nanopowder according to claim 6, characterized in that, A flow regulating valve is provided between the first precursor tank and the bottom burner, between the second precursor tank and the rotary burner, between the air tank and the bottom burner, between the air tank and the rotary burner, between the gas tank and the bottom burner, and between the gas tank and the rotary burner.

9. A method for flame synthesis of gadolinium-doped cerium oxide nanopowder, characterized in that, The flame synthesis apparatus for gadolinium-doped cerium oxide nanopowder according to any one of claims 1-8 includes the following steps: The air source and the gas source are turned on, the gas-air mixture is ignited, a preheating flame is formed at the outlet of the bottom burner, and a swirl burner forms a swirl flame above the bottom burner; The supply of the first precursor source and the second precursor source is turned on, and the first precursor and the second precursor are delivered to the bottom burner and the plurality of the rotary burners, so that the first precursor and the second precursor are broken into droplets and sprayed into the synthesis chamber. The droplets enter the synthesis chamber and undergo evaporation, combustion, thermal decomposition of metal salts, crystal nucleation and growth processes to transform into gadolinium-doped cerium oxide nanopowder materials, which are then discharged through the discharge port.

10. The flame synthesis method for gadolinium-doped cerium oxide nanopowder according to claim 9, characterized in that, The first precursor is a cerium nitrate solution or a mixed precursor solution, and the second precursor is a gadolinium nitrate solution or a mixed precursor solution. The preparation method of the mixed precursor solution includes the following steps: Gadolinium nitrate and isooctanoic acid were mixed and stirred to carry out a pre-complexation reaction until a gadolinium complex solution was formed; Dissolve the measured amount of cerium nitrate in anhydrous ethanol and stir until completely dissolved to form a cerium nitrate ethanol solution; The gadolinium complex solution was added dropwise to the cerium nitrate ethanol solution under continuous shearing and stirring. After the addition is complete, add isooctanoic acid to the mixture to bring the solution to the predetermined ratio, and stir. Acetic acid or butyric acid is added and mixed online, and the pH is measured until a predetermined pH is reached to form the mixed precursor solution.

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