Pulse spray evaporation flame synthesis method and device

Abstract

A pulsed spray evaporation flame synthesis method and device, the method comprising the following steps: atomizing and injecting a precursor solution in a pulsed manner, spraying it into a flame for reaction, and the precursor in the precursor solution forms a pre-prepared material core, deposits, and finally obtains a product. The present invention combines a pulsed spray evaporator with a flame spray pyrolysis method, precisely adjusts the concentration of the precursor in the liquid raw material, the spraying frequency and the opening time of the spray nozzle, thereby controlling the film thickness, the stoichiometry of the catalyst and the growth rate; at the same time, it also avoids the degradation of the device performance caused by the concentration fluctuation of the precursor solution.

Description

Technical Field

[0001] The present invention relates to the fields of chemical synthesis and combustion, and particularly to a pulsed spray evaporation flame synthesis method and apparatus. Background Art

[0002] Thin films and nanomaterials are widely used in modern technologies. For example, ferromagnetic thin films are used in computer storage devices, pharmaceuticals, thin film batteries, dye-sensitized solar cells, etc., and high-hardness ceramic thin films are used on cutting tools. Nanomaterials play a key role in many engineering fields, including energy (nanoelectronics, nanocatalytic materials, fossil fuel combustion), environment (air pollution, climate change), and biotechnology (medical diagnosis, drug delivery), etc. As people's requirements for the performance and advancement of thin film materials and nanoparticles are getting higher and higher, their efficient and controllable preparation has attracted more and more attention. According to the different principles of the preparation process, the methods for depositing thin films and nanoparticles can be divided into two categories: physical and chemical methods. The former includes mechanical grinding, physical vapor deposition (PVD), laser ablation, molecular beam epitaxy, thermal deposition, and sputtering methods, etc. Since physical methods are difficult to effectively control the particle size and the material preparation efficiency is relatively low, they are generally only applicable to specific materials. The latter mainly includes vapor deposition methods and solution techniques. The vapor deposition method is further divided into chemical vapor deposition (CVD) and atomic layer epitaxy (ALE). Solution techniques such as spray pyrolysis, sol-gel method, impregnation method, co-precipitation method, and spin coating method all require the use of precursor solutions. And methods with higher efficiency such as laser ablation, vapor deposition, and sol-gel method all require the use of professional equipment, such as vacuum units, high-power lasers, and expensive precursor materials. This results in extremely high costs for these methods. The advantage of flame spray pyrolysis is that the process is simple and it is easy to control the size of the final product. Specifically, it can dissolve the precursor in the fuel in advance, simplifying the process of feeding the precursor into the thermal reaction zone (flame reactor), and at the same time, it can flexibly use a high-speed atomizer to quickly quench the aerosol.

[0003] There have been some literatures studying different flame pyrolysis processes. For example, in 2002, researchers proposed a flame synthesis device that can synthesize nanomaterials by adjusting the flow rate of the oxidant and the composition of the precursor / fuel to control the specific surface area of the catalyst. In 2005, another researcher optimized the flame spray pyrolysis device for synthesizing perovskite mixed metal catalysts, mainly by using CH 4 / O 2Optimize the feed rate of the precursor solution based on the flow rate of the mixture, as well as the flow rate and linear velocity. In 2006, another piece of work focused on a novel flame synthesis method that uses gas and liquid precursors to produce nanoscale alumina catalysts. This method uses a high-temperature flame to heat the raw materials and sprays them into a condensation chamber, where they are condensed into nanoscale catalysts. In 2019, researchers proposed an improved version of the flame synthesis device for producing metals, non-oxide ceramics, and reduced metal oxide powders.

[0004] However, the efficiency of these methods is too low. The main problem is that there are processes of particle diffusion to the tube wall and thermophoresis in these methods, which lead to a too wide particle size distribution, are not applicable to the vast majority of cases, have extremely poor versatility, and low yields. And existing technologies generally use swirling flames and the technology of directly spraying the ultrasonically atomized precursor solution into the reaction chamber. It is very difficult to control the feeding frequency of the flame synthesis device and the duration of the atomized precursor solution, which may lead to fluctuations in the concentration of the precursor solution. Further affecting the particle size and properties of the final product, such as morphology and surface area.

[0005] In summary, a method that can balance cost-effectiveness and versatility and achieve the best results undoubtedly has great economic value. Summary of the Invention

[0006] In view of this, the main purpose of the present invention is to propose a pulsed spray evaporation flame synthesis method and device, in order to at least partially solve at least one of the above-mentioned technical problems.

[0007] As one aspect of the present invention, a pulsed spray evaporation flame synthesis method is provided, including the following steps:

[0008] Atomize and inject the precursor solution in a pulsed manner, spray it into the flame for reaction, and the precursor in the precursor solution forms a pre-prepared material core, deposits, and obtains the final product.

[0009] As another aspect of the present invention, a pulsed spray evaporation flame synthesis device is also provided, including:

[0010] A pulsed spray evaporator for pulsed atomization of the precursor solution;

[0011] A burner connected to the pulsed spray evaporator for generating a flame so that the precursor solution atomized in a pulsed manner reacts in the flame;

[0012] A collector for collecting the final product obtained after the precursor in the precursor solution forms a pre-prepared material core and deposits.

[0013] Based on the above technical solutions, the present invention has at least one or some of the following beneficial effects compared with the prior art:

[0014] (1) The present invention combines a pulsed spray evaporator (PSE) with a flame spray pyrolysis method to precisely adjust the precursor concentration in the liquid raw material, the spraying frequency of the spray nozzle, and the opening time (i.e., adjust the precursor flow rate), thereby controlling the film thickness, the stoichiometry of the catalyst, and the growth rate; at the same time, it also avoids the decline in device performance caused by fluctuations in the precursor solution concentration and does not increase costs;

[0015] (2) The present invention has low cost, high yield, simple process and is easy to scale up production. The synthesized catalyst has high activity, good selectivity and good stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a schematic flow diagram of the pulsed spray evaporation flame synthesis method according to an embodiment of the present invention;

[0017] Figure 2 is a schematic diagram of the pulsed spray evaporation flame synthesis device according to an embodiment of the present invention;

[0018] Figure 3 is a schematic bottom view of the burner according to an embodiment of the present invention;

[0019] Figure 4 is a schematic top view of the burner according to an embodiment of the present invention.

[0020] In the above drawings, the meanings of the reference numerals are as follows:

[0021] 1, 2, 3, 4 - flow controllers; 5, 6 - safety valves; 7 - storage tank; 8 - spray nozzle; 9 - pulse generator; 10 - heating tape; 11 - burner; 12 - flame; 13 - particles; 14 - final product; 15 - substrate; 16 - bracket; 17 - water pump; 18 - inlet valve; 19 - outlet valve; 20 - sample inlet; 21 - sample outlet; 22 - fuel gas inlet; 23 - fuel gas outlet; 24 - bath gas inlet; 25 - bath gas outlet; 26 - inlet and outlet of the cooling pipe. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] The present invention proposes a new flame spray pyrolysis method for synthesizing thin films or nanoparticles with strong stability and high activity. At the same time, the present invention also provides a pulsed spray evaporation flame synthesis device for realizing this method.

[0023] In order to make the purpose, technical solutions and advantages of the present invention clearer and more understandable, the following will further describe the present invention in detail with reference to specific embodiments and the accompanying drawings.

[0024] As an aspect of the present invention, there is provided a pulsed spray evaporation flame synthesis method, comprising the following steps:

[0025] The precursor solution is atomized and injected in a pulsed manner into a flame for reaction, and the precursor in the precursor solution forms a pre-prepared material core, which is deposited to obtain the final product.

[0026] In an embodiment of the present invention, the precursor solution is sprayed into the flame in the form of droplets formed by atomization and burns in the flame, and the precursor undergoes a pyrolysis reaction to form a pre-prepared material core; the pre-prepared material core can be understood as the powder formed by the pyrolysis of the precursor in the precursor solution by the flame; the powder is deposited to obtain the final product.

[0027] In an embodiment of the present invention, pulsed atomization injection is adopted to ensure the stable concentration of the precursor solution injection and the uniform morphology of the final product.

[0028] In an embodiment of the present invention, the pyrolysis reaction can be an oxidation reaction or a hydrolysis reaction, and metal oxides are produced by the pyrolysis reaction.

[0029] In an embodiment of the present invention, the final product includes a film-like substance or a nano-particle-like substance.

[0030] In an embodiment of the present invention, the final product can be a film-like substance or a nano-particle-like substance; the film-like structure or the nano-particle-like structure can be controlled by controlling the average deposition rate and the deposition time.

[0031] In an embodiment of the present invention, the thickness, stoichiometry and growth rate of the final product are controlled by the radio frequency and pulse width of the pulsed atomization injection.

[0032] In an embodiment of the present invention, for the pulsed atomization injection method, the radio frequency is less than 100 Hz; for example, 50 Hz, 30 Hz, 10 Hz, 5 Hz, 1 Hz.

[0033] In an embodiment of the present invention, the pulse width is in the millisecond order of magnitude; for example, 1 millisecond, 2 milliseconds, 5 milliseconds, 8 milliseconds, 10 milliseconds, 50 milliseconds.

[0034] In an embodiment of the present invention, the settings of the radio frequency and pulse width are suitable for the thickness order of magnitude of the final product to be between nanometers and micrometers and the weight order of magnitude to be milligrams.

[0035] In an embodiment of the present invention, the material of the final product includes noble metal oxides, transition metal oxides or perovskites.

[0036] In an embodiment of the present invention, the material of the final product includes one or more of iridium oxide, palladium oxide, ruthenium oxide, rhodium oxide, iron oxide, cerium oxide, aluminum oxide, chromium oxide, barium oxide, zinc oxide, lanthanum cobalt oxide, and lanthanum manganite.

[0037] In an embodiment of the present invention, the precursor solution includes a precursor and a combustible solvent.

[0038] In an embodiment of the present invention, the combustible solvent includes, but is not limited to, ethanol; it can also be other alcohol solvents, but ethanol has good stability and is cheap and easily available.

[0039] In an embodiment of the present invention, the precursor includes one or more of iridium acetylacetonate, palladium acetate, ruthenium acetate, rhodium acetylacetonate, iron acetylacetonate, cerium acetylacetonate, aluminum acetylacetonate, chromium acetylacetonate, barium acetylacetonate, zinc acetylacetonate hydrate, lanthanum acetylacetonate hydrate, cobalt acetylacetonate, manganese acetylacetonate, and lanthanum acetate hydrate.

[0040] When the prepared material thin film or particles are multi-metal compounds, a mixture is prepared by using multiple precursors.

[0041] Among them, the concentration of the precursor is in the order of millimoles per liter. For example, 1 millimole per liter, 10 millimoles per liter, 20 millimoles per liter, 100 millimoles per liter, 500 millimoles per liter.

[0042] In an embodiment of the present invention, according to the type and structure of the final product to be prepared, the corresponding precursor is selected and dissolved in the combustible solvent to prepare a precursor solution with a concentration in the mM order. For example, iron acetylacetonate (Fe(acac) 3 ) or cobalt acetylacetonate (Co(acac) 3 ) is dissolved in an ethanol solution to prepare a precursor solution required for the synthesis of iron-based or copper-based oxide materials.

[0043] In an embodiment of the present invention, before the precursor solution is atomized and injected into the flame in a pulsed manner to react, an oxidant is further added to the sample atomized and injected in a pulsed manner.

[0044] In an embodiment of the present invention, the oxidant includes air, but is not limited thereto. It can also be oxygen, or a gas mixture of oxygen and air mixed in a certain ratio. In an embodiment of the present invention, O 2 As an oxidant can increase the combustion speed of the droplets and make the final product stay at a higher temperature for a longer time. In addition, by measuring the flame spray temperature, it is found that the specific surface area of the final product synthesized using O 2 as an oxidant is smaller than that of the final product synthesized using air as an oxidant.

[0045] During the reaction process occurring in the injected flame, it also includes jointly injecting fuel, bath gas, and the precursor solution for pulsed atomization injection into the flame;

[0046] In an embodiment of the present invention, the fuel includes gaseous or liquid fuel; a mixture of alkanes such as methane and oxygen.

[0047] In an embodiment of the present invention, the bath gas may include nitrogen, but is not limited thereto, and may also be other inert gases such as argon.

[0048] In an embodiment of the present invention, the gas type can be replaced according to specific circumstances. The flow rate of each gas path is controlled by a flow controller to achieve a suitable flame.

[0049] In an embodiment of the present invention, the flame height is 5 - 15 cm; the temperature range is 1500 - 2000 °C.

[0050] In an embodiment of the present invention, the evaporation of the solvent in the precursor solution and the pyrolysis of the precursor occur instantaneously simultaneously in the flame. The flame height and the flame temperature are important factors affecting the particle size, specific surface area, morphology, crystal form, and other structures of the final product formed after the pyrolysis of the precursor.

[0051] In an embodiment of the present invention, in combination with pulsed atomization injection, the flame height is preferably 5 - 15 cm; the temperature range is preferably 1500 - 2000 °C.

[0052] As another aspect of the present invention, there is also provided a pulsed spray evaporation flame synthesis device, including:

[0053] A pulsed spray evaporator for pulsed atomization of the precursor solution;

[0054] A burner connected to the pulsed spray evaporator for generating a flame so that the precursor solution for pulsed atomization injection reacts in the flame;

[0055] A collector for collecting the final product obtained after the precursor in the precursor solution forms a pre-prepared material nucleus and deposits.

[0056] In an embodiment of the present invention, the pulsed spray evaporator includes a spray nozzle, an evaporation tube, and a pulse generator;

[0057] The pulse generator is connected to the spray nozzle for controlling the pulsed atomization injection of the spray nozzle;

[0058] The spray nozzle includes a spray nozzle outlet; the spray nozzle outlet is connected to one end of the evaporation tube;

[0059] The evaporation tube, the other end of the evaporation tube is connected to the burner.

[0060] In an embodiment of the present invention, an evaporation tube is provided between the spray nozzle and the burner, which facilitates controlling the injection frequency of the precursor solution and the opening time of the spray nozzle, thereby controlling the thickness, stoichiometry, growth rate, etc. of the final product.

[0061] In an embodiment of the present invention, the device combines a pulsed spray evaporation flame synthesis method. Since for the currently used pulsed spray evaporator, the droplet size of the precursor solution entering the burner is limited; different spray nozzle diameters can be used to meet the operation requirements to overcome the different requirements for the pulse frequency and droplet diameter due to this limitation.

[0062] In an embodiment of the present invention, the device further includes a heating tape, which is wound around the outer wall of the evaporation tube.

[0063] In other embodiments of the present invention, multiple groups of spray nozzles and pulse generators can be provided, and each group of spray nozzles sprays different precursor solutions to obtain a final product with a multi-layer or superlattice structure.

[0064] In an embodiment of the present invention, the device further includes an oxidant pipeline, which is connected to the evaporation tube and used to transport oxidant into the evaporation tube.

[0065] In an embodiment of the present invention, the oxidant pipeline is connected to the evaporation tube. On the one hand, the oxidant is fully mixed with the atomized sample. As a reaction raw material, the oxidant is beneficial to the uniformity of the subsequent combustion reaction in the flame. On the other hand, the injection of the oxidant further breaks up the droplets of the atomized sample, playing a role in further assisting atomization. On the other hand, the flow of the oxidant in the evaporation tube is also beneficial to the transportation of the atomized sample in the evaporation tube.

[0066] In an embodiment of the present invention, the burner includes a burner body, and the burner body includes:

[0067] A central channel, which is provided at the central axis of the burner body. One end of the central channel is connected to the evaporation tube, and the other end of the central channel is provided as a sample outlet, and the sample outlet is connected to the flame generation side of the burner body;

[0068] A fuel gas channel, one end of the fuel gas channel is provided with a fuel gas inlet, and the other end of the fuel gas channel is provided with a fuel gas outlet. The fuel gas outlet of the fuel gas channel is arranged in a ring along the periphery of the central channel;

[0069] A bath gas channel, one end of the bath gas channel is provided with a bath gas inlet, and the other end of the bath gas channel is provided with a bath gas outlet. The bath gas outlet of the bath gas channel is arranged in a ring along the periphery of the fuel gas outlet.

[0070] In an embodiment of the present invention, the burner further includes a cooling pipe disposed in the internal space of the burner body for cooling the burner; the inlet and outlet of the cooling pipe are respectively connected to a connecting pipe to form a circulation flow path, and a water pump, a water tank and a control valve are provided on the connecting pipe.

[0071] In an embodiment of the present invention, the device further includes a fuel gas supply pipe connected to the fuel gas inlet; a safety valve is provided on the fuel gas supply pipe; and a bath gas supply pipe connected to the bath gas inlet.

[0072] In an embodiment of the present invention, a plurality of branch supply pipes are provided on the side of the fuel gas supply pipe opposite to the fuel gas inlet end; a flow controller is provided on each branch supply pipe;

[0073] A flow controller is provided on the bath gas supply pipe.

[0074] In an embodiment of the present invention, the collector includes a substrate and a bracket, the substrate is disposed on the bracket; the bracket faces the burner outlet;

[0075] In an embodiment of the present invention, the substrate can be a stainless steel mesh, but is not limited thereto, and can also be a metal mesh, a metal sheet, a tin foil sheet or glass, as long as it is a non-catalytic or non-reactive surface.

[0076] In an embodiment of the present invention, the device further includes a limiter disposed between the burner and the collector for enabling the final product to be directionally deposited on the substrate.

[0077] The technical solution of the present invention will be further described below in conjunction with specific embodiments. It should be noted, however, that the following embodiments are only used to illustrate the technical solution of the present invention, but the present invention is not limited thereto.

[0078] As Figure 1 shown, the method of the present invention includes the following steps:

[0079] (1) Prepare a precursor solution.

[0080] (2) Inject fuel and bath gas. The fuel and the bath gas are regulated and introduced into the burner through their respective flow controllers.

[0081] (3) Pulse atomization injection of the precursor solution. This step is carried out simultaneously with step (2). The precursor solution prepared in step (1) is atomized and fed into the combustion chamber using a spray nozzle equipped with a pulse generator, and an oxidant is added to the atomized precursor solution at the same time. It burns together with the fuel in step (2) to generate a flame.

[0082] (4) Flame and precursor evaporation. The fuel, bath gas, oxidant, and precursor solution in steps (2) and (3) together generate combustion. Meanwhile, the precursor solution in the flame evaporates to form nuclei of the pre-prepared material, which then grow through coalescence. This is affected by the solvent used in step (3) and the flow rate of the gas in step (2).

[0083] (5) Deposition of thin film or particles. The generated powder is deposited on the substrate on the bottom support in the form of a thin film or nanoparticles.

[0084] (6) Material collection. The thin film deposited on the substrate is directly taken out, and the particulate material deposited on the substrate needs to be scraped off and collected.

[0085] (7) In step (3), by adjusting the precursor concentration in the liquid raw material, the spraying frequency, and the opening time of the spray nozzle, the thickness, stoichiometry, and growth rate of the catalyst thin film obtained in step (5) can be controlled.

[0086] The liquid raw material is maintained at room temperature, at which no obvious thermal degradation occurs, so the repeatability of the thin film growth process is relatively good.

[0087] (8) Depending on the reactants, the nanoparticles or thin films obtained in steps (5) and (6) can be noble metal oxides, transition metal oxides, or perovskites, such as iridium oxide, palladium oxide, ruthenium oxide, rhodium oxide, iron oxide, cerium oxide, aluminum oxide, chromium oxide, zinc oxide, lanthanum cobalt oxide, and lanthanum manganese oxide.

[0088] The present invention also provides a pulsed spray evaporation flame synthesis device. As Figure 2 、 Figure 3 and Figure 4 shown, the device includes five parts: a gas supply unit, a liquid vaporization sampling unit, a combustion unit, a cooling unit, and a thin film / particle collection unit.

[0089] (1) The gas supply unit contains four gases, oxidant 1, oxidant 2, fuel gas, and protective gas, which can be air, O 2 , CH 4 and N 2 , and can also be replaced according to actual situations. Each gas supply pipe is responsible for delivering the four gases into the burner, and flow controllers, such as flow controllers 1, 2, 3, and 4, are provided on each gas supply pipe; each flow controller can adjust the flow rate manually or through a control unit.

[0090] (2) The liquid vaporization sampling unit includes a liquid raw material storage tank 7, a spray nozzle 8, a pulse generator 9, and an evaporation tube. Among them, a heating tape 10 is wound around the evaporation tube.

[0091] (3) The combustion unit includes a burner 11. The burner includes a burner body which includes a central channel disposed at the central axis of the burner body. One end of the central channel is set as a sample inlet 20 connected to an evaporation tube, and the other end of the central channel is set as a sample outlet 21 which is in communication with the flame generation side of the burner body;

[0092] A fuel gas channel, one end of the fuel gas channel is provided with a fuel gas inlet 22, the other end of the fuel gas channel is provided with a fuel gas outlet 23, and the fuel gas outlet 23 is in communication with the flame generation side of the burner; the fuel gas outlet 23 of the fuel gas channel is arranged in a ring along the periphery of the central channel;

[0093] A bath gas channel, one end of the bath gas channel is provided with a bath gas inlet 24, the other end of the bath gas channel is provided with a bath gas outlet 25, and the bath gas outlet 25 is in communication with the flame generation side of the burner; the bath gas outlet 25 of the bath gas channel is arranged in a ring along the periphery of the fuel gas outlet 23.

[0094] In an embodiment of the present invention, the burner further includes a cooling tube disposed in the internal space of the burner for cooling the burner; the inlet and outlet 26 of the cooling tube are respectively connected to a connecting tube for forming a circulation flow path, and a water pump, a water tank and a control valve are arranged on the connecting tube.

[0095] The burner 11 includes a central channel, a bath gas channel, a fuel gas channel and a cooling tube. The precursor flows out from the central channel of the burner 11, while the dispersed fuel gas flows out from the fuel gas outlet 23 (annular gap) of the fuel gas channel. The bath gas is ejected from the bath gas outlet 25. The burner body is made of stainless steel and silica, and has good thermal stability, chemical stability, high temperature resistance and acid corrosion resistance. Two safety valves (safety valve 5 and safety valve 6) are installed on the methane and oxygen supply pipes to prevent the flame 12 from flowing back into the methane and oxygen supply pipes.

[0096] (4) The cooling unit includes a water pump 17, an inlet valve 18, an outlet valve 19 and a connecting tube equipped with the water pump.

[0097] (5) The particle collection unit includes newly formed particles 13, the deposited final product 14, i.e., a film or nanoparticles, a substrate 15 and a bracket 16.

[0098] Example 1

[0099] Iron acetylacetonate (Fe(acac) 3 ) was dissolved in an ethanol solution to prepare a precursor solution required for synthesizing an iron-based oxide material, and the concentration of the precursor solution was: 0.02 - 0.5 M;

[0100] The spraying frequency of the spray nozzle was 25 - 50 Hz, and the opening time was 2 - 10 ms;

[0101] An iron oxide film product is obtained, with a film thickness between 50 and 150 μm and a nano-particle size of 10 - 30 nm.

[0102] Example 2

[0103] Cobalt acetylacetonate (Co(acac) 3 ) is dissolved in an ethanol solution to prepare a precursor solution required for the synthesis of cobalt-based oxide materials. The concentration of the precursor solution is: 0.02 - 0.5 M;

[0104] The spraying frequency of the spray nozzle is 10 - 25 Hz, and the opening time is 2 - 10 ms;

[0105] A cobalt oxide granular product is obtained, with a nano-particle size of 30 - 45 nm.

[0106] Comparative Example 1

[0107] Using iron acetylacetonate (Fe(acac) 3 ) as a precursor, an iron oxide catalyst is prepared by the sol-gel method. The obtained particle size is in the range of 40 - 70 nm.

[0108] Comparative Example 2

[0109] Using iron acetylacetonate (Fe(acac) 3 ) as a precursor, the same iron oxide prepared by the wet impregnation method has a particle size of 80 - 100 nm.

[0110] In the above specific embodiments, the purpose, technical solution and beneficial effects of the present invention are further described in detail. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A pulsed spray evaporation flame synthesis method using a pulsed spray evaporation flame synthesis device, characterized in that, the method comprises the following steps: The precursor solution is atomized and injected in a pulsed manner into the flame for reaction. The precursor in the precursor solution forms a pre-prepared material core, deposits, and the final product is obtained; wherein, the pulsed spray evaporation flame synthesis device includes: A pulsed spray evaporator for pulsed atomization of the precursor solution; A burner connected to the pulsed spray evaporator for generating a flame so that the precursor solution atomized and injected in a pulsed manner reacts in the flame; A collector for collecting the final product obtained after the precursor in the precursor solution forms a pre-prepared material core and deposits; wherein, the pulsed spray evaporator includes a spray nozzle, an evaporation tube, and a pulse generator; The pulse generator is connected to the spray nozzle for controlling the pulsed atomization injection of the spray nozzle; The spray nozzle includes a spray nozzle outlet; the spray nozzle outlet is connected to one end of the evaporation tube; The evaporation tube, the other end of the evaporation tube is connected to the burner; wherein, the device further includes: an oxidant pipeline, the oxidant pipeline is connected to the evaporation tube for delivering oxidant into the evaporation tube; wherein, the burner includes: a burner body, the burner body includes: a central channel disposed at the central axis of the burner body, one end of the central channel is connected to the evaporation tube, the other end of the central channel is provided as a sample outlet, and the sample outlet is connected to the flame generation side of the burner body; a fuel gas channel, one end of the fuel gas channel is provided with a fuel gas inlet for delivering oxygen and fuel gas, the other end of the fuel gas channel is provided with a fuel gas outlet, and the fuel gas outlet is connected to the flame generation side of the burner; the fuel gas outlet of the fuel gas channel is arranged in a ring along the periphery of the central channel; a bath gas channel, one end of the bath gas channel is provided with a bath gas inlet, the other end of the bath gas channel is provided with a bath gas outlet, and the bath gas outlet is connected to the flame generation side of the burner; the bath gas outlet of the bath gas channel is arranged in a ring along the periphery of the fuel gas outlet; wherein, multiple groups of the spray nozzle and the pulse generator are provided, and each group of the spray nozzles sprays different precursor solutions so as to obtain the final product with a multi-layer or superlattice structure.

2. The pulsed spray evaporation flame synthesis method according to claim 1 ， characterized in that, wherein, the burner further includes a cooling tube disposed in the internal space of the burner body for cooling the burner; the inlet and outlet of the cooling tube are respectively connected to a connecting pipe for forming a circulation flow path, and a water pump, a water tank, and a control valve are arranged on the connecting pipe; wherein, the device further includes: a fuel gas supply pipe connected to the fuel gas inlet; a safety valve disposed on the fuel gas supply pipe; a bath gas supply pipe connected to the bath gas inlet; Wherein, a plurality of branch gas supply pipes are provided on the side of the fuel gas supply pipe opposite to the fuel gas inlet end; Wherein, a flow controller is provided on each of the branch gas supply pipes; Wherein, a flow controller is provided on the bath gas supply pipe; Wherein, the device further comprises: a heating tape wound around the outer wall of the evaporation tube; Wherein, the collector comprises a substrate and a bracket, and the substrate is arranged on the bracket; Wherein, the substrate comprises a stainless steel mesh, a metal mesh, a metal sheet, a tin foil or glass; Wherein, the device further comprises a limiter arranged between the burner and the collector for enabling the final product to be directionally deposited on the substrate.

3. The pulsed spray evaporation flame synthesis method according to claim 1, characterized in that, The pulsed atomization injection method has a radio frequency less than 100 Hz; the pulse width is in the millisecond order of magnitude.

4. The pulsed spray evaporation flame synthesis method according to claim 1, characterized in that, The final product comprises a film-like substance or a nano-particle-like substance; The thickness order of magnitude of the final product is between nanometers and micrometers, and the weight order of magnitude is milligrams; the material of the final product comprises a noble metal oxide, a transition metal oxide or a perovskite.

5. The pulsed spray evaporation flame synthesis method according to claim 4, characterized in that, The material of the final product comprises one or more of iridium oxide, palladium oxide, ruthenium oxide, rhodium oxide, iron oxide, cerium oxide, aluminum oxide, chromium oxide, barium oxide, zinc oxide, lanthanum cobalt oxide, lanthanum manganate.

6. The pulsed spray evaporation flame synthesis method according to claim 1, characterized in that, The precursor solution comprises a precursor and a combustible solvent; The combustible solvent comprises ethanol; The precursor comprises one or more of iridium acetylacetonate, palladium acetate, ruthenium acetate, rhodium acetylacetonate, iron acetylacetonate, cerium acetylacetonate, aluminum acetylacetonate, chromium acetylacetonate, barium acetylacetonate, zinc acetylacetonate hydrate, lanthanum acetylacetonate hydrate, cobalt acetylacetonate hydrate, manganese acetylacetonate hydrate, lanthanum acetate hydrate; Wherein, the concentration of the precursor is in the order of millimoles per liter.

7. The pulsed spray evaporation flame synthesis method according to claim 1, characterized in that, Before the precursor solution is injected into the flame in a pulsed atomization manner for reaction, it further comprises: Adding an oxidant to the sample injected in a pulsed atomization manner; Wherein, the oxidant comprises air or oxygen.

8. The pulsed spray evaporation flame synthesis method according to claim 1, characterized in that, The injection into the flame for reaction further comprises: Injecting fuel and bath gas into the flame simultaneously; Wherein, the fuel comprises a gaseous or liquid fuel; The bath gas comprises nitrogen or argon; The flame height is 5 - 15 cm; the temperature range is 1500 - 2000 °C.

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