An electrocatalyst, its preparation method and application

Abstract

This invention provides an electrocatalyst, its preparation method, and its application. The electrocatalyst comprises a support and an active component. The support is a reducible oxide conductive support, and the active component comprises a redox component and an acidic component. The active component is embedded in the crystal lattice surface of the support in a single-atom form; the mass ratio of the redox component to the acidic component is 1:(0.5-2). This invention introduces a specific ratio of redox component and acidic component embedded in the crystal lattice surface of the support in a single-atom form. The two components work synergistically to efficiently match the flowing charge on the surface of the electrocatalyst and achieve full utilization of the unit redox component. This allows the electrocatalyst to adapt to the special characteristics of electrically driven removal of atmospheric pollutants, achieving a balance between acidic and redox performance at ultra-low temperatures under energized conditions, enabling efficient conversion of atmospheric pollutants at ultra-low temperatures and within a wide temperature window.

Description

Technical Field

[0001] This invention belongs to the field of environmental protection and air pollution control technology, specifically relating to an electrocatalyst, its preparation method, and its application. Background Technology

[0002] With the advancement of large-scale industrialization, a large amount of fossil fuel coal has been consumed, generating numerous air pollutants. Among these pollutants, nitrogen oxides (nitrogen oxides, including NO and NO2) are among the most serious air pollutants. The emission of nitrogen oxides causes various environmental problems, such as the combined pollution of fine particulate matter and ozone (PM2.5-O3), the greenhouse effect, smog, and acid rain. Ammonia selective catalytic reduction (ACR) is the most widely adopted and mature denitrification method. V2O5-WO3(MoO3) / TiO2 is widely used in the thermal power industry due to its high nitrogen selectivity and strong resistance to sulfur poisoning. This catalyst exhibits excellent performance in the medium-high temperature range (300-450℃). However, its activity decreases significantly at ultra-low temperatures (<150℃), hindering its application in treating low-temperature flue gas. Therefore, it is of great significance to prepare a denitrification catalyst with high activity at ultra-low temperatures, a wide temperature window, high nitrogen selectivity, and low cost. The acidity and redox properties of the catalyst system are important factors affecting its catalytic performance, with redox properties being particularly important at low temperatures. Designing catalysts that balance acidity and redox performance at low temperatures and constructing efficient low-temperature selective catalytic reduction of ammonia remains a challenge.

[0003] To address the need for improved redox properties at low temperatures, CN112984535A discloses an electrically assisted method for highly efficient catalytic combustion of soot. Compared to traditional thermal ignition of soot, this external field-assisted approach enables highly efficient catalysis at lower temperatures. CN109999658A discloses an electrically driven catalytic reaction device and its application, providing detailed information on the catalytic reaction device and its application. While the aforementioned electrically assisted methods can achieve highly efficient catalysis at low temperatures, they do not address the more complex multi-gas molecule reaction processes, and the efficient preparation of electrically assisted catalysts still lacks design principles.

[0004] Therefore, it is crucial to improve the utilization rate of unit redox components and effectively match microcurrents to achieve more efficient catalytic activity. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide an electrocatalyst, its preparation method, and its applications. This invention introduces a specific ratio of redox components and acidic components embedded in the crystal lattice surface of a support in a single-atom form. The two components work synergistically to efficiently match the flowing charge on the electrocatalyst surface and achieve full utilization of the unit redox component, achieving two goals at once. This allows the electrocatalyst to adapt to the specific characteristics of electrically driven removal of atmospheric pollutants, achieving a balance between acidic and redox performance at ultra-low temperatures under energized conditions. This enables efficient conversion of atmospheric pollutants at ultra-low temperatures and within a wide temperature window, exhibiting advantages such as high low-temperature activity, a wide operating temperature window, significant energy-saving effects, high stability, and high applicability.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides an electrocatalyst comprising a support and an active component, wherein the support is a reducible oxide conductive support, and the active component comprises a redox component and an acidic component, wherein the active component is embedded in the crystal lattice surface of the support in a single-atom form.

[0008] The mass ratio of the redox component to the acidic component is 1:(0.5-2).

[0009] This invention introduces a specific ratio of redox components and acidic components embedded in the crystal lattice surface of a support in a single-atom form. The two work synergistically to efficiently match the flowing charge on the surface of the electrocatalyst and achieve full utilization of the unit redox component, achieving "two birds with one stone". This allows the electrocatalyst to adapt to the special characteristics of electrically driven removal of atmospheric pollutants, achieving a balance between acidic and redox performance in the ultra-low temperature stage under energized conditions. This enables it to achieve efficient conversion of atmospheric pollutants at ultra-low temperatures and within a wide temperature window, and has advantages such as high low-temperature activity, wide operating temperature window, significant energy-saving effect, high stability, and high applicability.

[0010] In this invention, the mass ratio of the redox component to the acidic component is 1:(0.5-2), for example, it can be 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9 or 1:2, etc.

[0011] In this invention, if the mass ratio of the redox component to the acidic component is too small, that is, the content of the acidic component is too large, the acidic ability in the catalytic reaction is stronger than the redox ability, and the two cannot cooperate synergistically; if the mass ratio of the redox component to the acidic component is too large, that is, the content of the acidic component is too small, the redox ability in the catalytic reaction is stronger than the acidic ability, and the two cannot cooperate synergistically.

[0012] As a preferred embodiment of the present invention, the reducible oxide conductive carrier is a tin dioxide-based oxide material doped with heteroelement.

[0013] In this invention, the tin ions in tin dioxide that are doped with different elements can improve its band gap and electrical conductivity.

[0014] Preferably, the heteroelement includes any one or a combination of at least two of F, In, Sb, P, Cl or Te.

[0015] Preferably, the reducible oxide conductive carrier includes any one or a combination of at least two of fluorine-doped tin dioxide (FTO), indium-doped tin dioxide (ITO), or antimony-doped tin dioxide (ATO), with antimony-doped tin dioxide (ATO) being the most preferred.

[0016] It should be noted that ATO, as a carrier, can exhibit superior catalytic performance.

[0017] As a preferred embodiment of the present invention, the redox component is any one or a combination of at least two of copper oxide, cerium oxide, iron oxide, vanadium pentoxide, or cobalt oxide, preferably any one or a combination of at least two of vanadium pentoxide, iron oxide, or copper oxide.

[0018] It should be noted that the cation radius of the redox component must be similar to that of the tin ion in order to achieve the substitution of the tin ion and complete the intercalation.

[0019] Preferably, the acidic component is an acidic metal oxide, which includes any one or a combination of at least two of niobium oxide, tungsten oxide, titanium oxide, molybdenum oxide, lanthanum oxide, or praseodymium oxide, and is more preferably a combination of any one or at least two of niobium oxide, tungsten oxide, or molybdenum oxide.

[0020] It should be noted that the cation radius of the acidic component must be similar to that of the tin ion in order to achieve the substitution of the tin ion and complete the intercalation.

[0021] Preferably, the loading of the redox component on the support is 0.1-5%, for example, it can be 0.1%, 0.5%, 1%, 2%, 3%, 4% or 5%, etc., preferably 1-3%.

[0022] In this invention, the loading amount of the redox component needs to be matched with the specific surface area of ​​the support so that the redox component can exhibit an atomically dispersed state. If the loading amount of the redox component on the support is too small, there will be too few redox sites on the catalyst, failing to achieve the purpose of efficient removal of nitrogen oxides; if the loading amount of the redox component on the support is too large, some of the redox components on the catalyst will not exhibit an atomically dispersed state.

[0023] Preferably, the loading of the acidic component on the carrier is 0.1-10%, for example, it can be 0.1%, 1%, 3%, 5%, 7%, 9% or 10%, and more preferably 1-6%.

[0024] In this invention, the loading amount of the acidic component needs to be matched with the specific surface area of ​​the support so that the acidic component can be in an atomically dispersed state. If the loading amount of the acidic component on the support is too small, there will be too few acidic sites on the catalyst, and the purpose of efficient removal of nitrogen oxides will not be achieved; if the loading amount of the acidic component on the support is too large, some of the acidic components on the catalyst will not be in an atomically dispersed state.

[0025] In a second aspect, the present invention provides a method for preparing an electrocatalyst as described in the first aspect, the method comprising the following steps:

[0026] (1) Mix the precursor of the redox component, the precursor of the acid component and the solvent to obtain a precursor solution of the active component;

[0027] (2) The precursor solution of the active component and the reducible oxide conductive support are mixed and calcined to obtain the electrocatalyst.

[0028] The preparation method provided by this invention is simple, low-cost, and widely applicable, offering an efficient, economical, and widely applicable preparation route for the practical application of electrocatalysts.

[0029] As a preferred technical solution of the present invention, the precursor of the redox component in step (1) includes nitrate.

[0030] Preferably, the nitrate includes any one or a combination of at least two of copper nitrate, cerium nitrate, ferric nitrate, ammonium metavanadate, or cobalt nitrate.

[0031] Preferably, the precursor of the acidic component in step (1) includes any one or a combination of at least two of ammonium niobate oxalate, ammonium metatungstate, tetrabutyl titanate, ammonium molybdate, lanthanum nitrate, or praseodymium nitrate.

[0032] As a preferred technical solution of the present invention, the reducible oxide conductive carrier in step (2) is a tin dioxide-based oxide material doped with heteroelement. The preparation method of the tin dioxide-based oxide material doped with heteroelement includes any one or a combination of at least two of the following: chemical coprecipitation method, hydrothermal method, solvent method, combustion method or sol-gel method, preferably the chemical coprecipitation method.

[0033] The method for preparing reducible oxide conductive carriers used in this invention can achieve a wide range of control over the conductivity of the conductive carrier, theoretically breaking through the limitations on the control of the conductivity of the conductive carrier and making it adaptable to various testing conditions.

[0034] Preferably, in the chemical coprecipitation method, the sintering temperature is 400-600℃, for example, 400℃, 450℃, 500℃, 550℃ or 600℃, and the sintering time is 1-8h, for example, 1h, 2h, 3h, 4h, 5h, 6h, 7h or 8h.

[0035] Preferably, the mixing method in step (2) includes any one or a combination of at least two of co-impregnation, hydrothermal method or solvent method, with co-impregnation being the preferred method.

[0036] In this invention, the redox component and the acidic component can be embedded into the carrier by any one or a combination of at least two of the following methods: co-impregnation, hydrothermal method, or solvent method.

[0037] Preferably, the mixing process in step (2) is accompanied by ultrasound.

[0038] In this invention, the role of ultrasound is to promote dispersion.

[0039] Preferably, the roasting temperature in step (2) is 300-600℃, for example, it can be 300℃, 350℃, 400℃, 450℃, 500℃, 550℃ or 600℃, and the roasting time is 1-8h, for example, it can be 1h, 2h, 3h, 4h, 5h, 6h, 7h or 8h.

[0040] In this invention, if the calcination temperature is too low, the atoms of the redox components and acidic components cannot be embedded in the crystal lattice surface of the carrier in an atomic state; if the calcination temperature is too high, the crystal lattice structure of the conductive carrier will be destroyed.

[0041] As a preferred technical solution of the present invention, the preparation method includes the following steps:

[0042] (I) A heteroelement-doped tin dioxide-based oxide material is prepared by chemical co-precipitation, wherein the sintering temperature is 400-600℃ and the sintering time is 1-8h, and the heteroelement includes any one or at least two combinations of F, In, Sb, P, Cl or Te.

[0043] (II) Disperse the precursors of the redox component and the acidic component with loadings of 0.1-5% and 0.1-10% respectively in a solvent to obtain a precursor solution of the active component;

[0044] (III) The precursor solution of the active component and the tin dioxide-based oxide material doped with heteroelement are mixed by co-impregnation method. The mixing process is accompanied by ultrasound, and then calcined at 300-600℃ for 1-8 hours. After calcination, the electrocatalyst is obtained.

[0045] Thirdly, the present invention provides an application of the electrocatalyst as described in the first aspect, wherein the electrocatalyst is used for the catalytic reduction and removal of gaseous pollutants;

[0046] The gaseous pollutants include nitrogen oxides.

[0047] The present invention does not limit the specific types of nitrogen oxides. For example, it may be a gaseous substance containing both nitrogen and oxygen elements, such as nitric oxide or nitrogen dioxide.

[0048] As a preferred embodiment of the present invention, the catalytic reduction removal of gaseous pollutants includes the following steps:

[0049] (a) Apply DC power to both ends of the electrocatalyst to make the electrocatalyst in a conductive state;

[0050] (b) A gaseous pollutant containing nitrogen oxides is introduced into the container containing the electrocatalyst in the conducting state to carry out a catalytic reduction reaction.

[0051] It should be noted that the electrocatalyst is filled in the container, and porous conductive copper filter sheets are placed at both ends. The two ends of the conductive copper filter sheets are connected to electrodes, and the electrodes are connected to the positive and negative terminals of the DC power supply. When the DC power supply is turned on, the electrocatalyst is in a conductive state.

[0052] As a preferred technical solution of the present invention, the output power of the DC power supply in step (a) is 1-50W, for example, it can be 1W, 5W, 10W, 20W, 30W, 40W or 50W, and the output voltage is 1-20V, for example, it can be 1V, 5V, 10V, 15V or 20V.

[0053] Preferably, the temperature of the catalytic reduction reaction is 50-500℃, for example, it can be 50℃, 100℃, 200℃, 300℃, 400℃ or 500℃, etc., preferably 50-300℃.

[0054] Preferably, the composition of the nitrogen oxide-containing gaseous pollutant in step (b) includes: 0-5000 ppm nitrogen oxides, 0-5000 ppm ammonia, 0-20% oxygen by volume, and nitrogen as a balance gas.

[0055] In this invention, nitrogen oxides are present in the range of 0-5000 ppm, for example, 500 ppm, 1000 ppm, 2000 ppm, 3000 ppm, 4000 ppm, or 5000 ppm. Ammonia is present in the range of 0-5000 ppm, for example, 500 ppm, 1000 ppm, 2000 ppm, 3000 ppm, 4000 ppm, or 5000 ppm. Oxygen is present in the range of 0-20% by volume, for example, 5%, 10%, 15%, or 20%.

[0056] Preferably, the mass hourly space velocity (MSV) of the nitrogen oxide-containing gaseous pollutant in step (b) is 0-500000 mL / (h·g), for example, it can be 10000 mL / (h·g), 50000 mL / (h·g), 100000 mL / (h·g), 250000 mL / (h·g), etc., and is more preferably 10000-200000 mL / (h·g).

[0057] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0058] Compared with the prior art, the present invention has the following beneficial effects:

[0059] (1) This invention introduces a specific ratio of redox components and acidic components embedded in the lattice surface of the support in the form of single atoms. The two work together to efficiently match the flowing charge on the surface of the electrocatalyst and realize the full utilization of the unit redox component, achieving "two birds with one stone". This allows the electrocatalyst to adapt to the special characteristics of electric drive to remove atmospheric pollutants, and achieve a balance between acidic and redox performance in the ultra-low temperature stage under energized conditions. This enables it to achieve efficient conversion of atmospheric pollutants at ultra-low temperatures and in a wide temperature window. It has the advantages of high low-temperature activity, wide operating temperature window, significant energy saving effect, high stability and high applicability.

[0060] (2) The preparation method provided by the present invention is simple, low in cost, and has a wide range of applications, providing an efficient, economical and widely applicable preparation route for the practical application of electrocatalysts. Attached Figure Description

[0061] Figure 1 This is a schematic diagram of the spherical aberration of the electrocatalyst prepared in Example 1 of this invention.

[0062] Figure 2 This is a schematic diagram of the spherical aberration of the electrocatalyst prepared in Comparative Example 1 of this invention. Detailed Implementation

[0063] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0064] Example 1

[0065] This embodiment provides a method for preparing an electrocatalyst, the method comprising the following steps:

[0066] (1) Preparation of ATO conductive carrier

[0067] Weigh 1.728g of SnCl4 and dissolve it in 200mL of anhydrous ethanol. Then add 0.172g of SbCl3 and stir continuously. Then add 50mL of methanol to obtain a mixed solution. Add the mixed solution to a large beaker sealed with a membrane and containing a large amount of ammonium carbonate and stir. After the diffusion precipitation reaction is complete, wash the obtained precipitate 8 times by centrifuge (6 times with 50% ethanol and 2 times with 100% ethanol) to obtain the ATO precursor.

[0068] The ATO precursor was dried in an oven at 70°C for 24 hours to obtain a yellow powder. The powder was then ground into a crucible and calcined at high temperature in a muffle furnace at a heating rate of 0.5°C / min. The temperature was maintained at 600°C for 2 hours. After cooling, a dark blue ATO conductive carrier was obtained.

[0069] (2) Dissolve 1g of ammonium metavanadate in 10mL of oxalic acid solution (10wt%) to prepare ammonium metavanadate solution, and dissolve 1g of ammonium niobate in 10mL of ultrapure water to prepare ammonium niobate solution; at the same time, add 1g of the ATO conductive carrier to 5mL of oxalic acid solution and stir continuously to obtain ATO conductive carrier solution.

[0070] (3) Using a pipette, 282 μL of ammonium metavanadate solution and 230 μL of ammonium niobate oxalate solution were added to the ATO conductive support solution and stirred continuously at 70°C and 100 rpm for 24 h. The mixture was then collected in a beaker and dried in an oven at 80°C for 12 h to obtain a sample. The sample was ground and transferred to a crucible and calcined at 500°C at a heating rate of 5°C / min for 4 h. The electrocatalyst was obtained after the calcination was completed.

[0071] This embodiment also provides an electrocatalyst prepared by the above method. The electrocatalyst includes a support and an active component. The support is an ATO conductive support, and the active component includes a redox component and an acidic component. The active component is embedded in the crystal lattice surface of the support in a single-atom form.

[0072] The redox component is loaded at 2% on the ATO conductive carrier, the acidic component is loaded at 1% on the ATO conductive carrier, the mass ratio of the redox component to the acidic component is 1:0.5, the redox component is vanadium pentoxide, and the acidic component is niobium oxide.

[0073] Figure 1 A schematic diagram of the aberration of the electrocatalyst prepared in this embodiment is shown. As can be seen from the figure, the redox components and acidic components are embedded in the lattice surface of the support in the form of single atoms.

[0074] Example 2

[0075] The difference between this embodiment and embodiment 1 is that ammonium metavanadate in step (2) is replaced with ammonium molybdate, so that the acidic component in the electrocatalyst is molybdenum oxide.

[0076] The remaining preparation methods and parameters are consistent with those in Example 1.

[0077] Example 3

[0078] The difference between this embodiment and embodiment 1 is that the ammonium niobate oxalate in step (2) is replaced with ammonium metatungstate, so that the acidic component in the electrocatalyst is tungsten oxide.

[0079] The remaining preparation methods and parameters are consistent with those in Example 1.

[0080] Example 4

[0081] The difference between this embodiment and embodiment 1 is that the ammonium metavanadate solution in step (2) is replaced with ferric nitrate solution, that is, 1g of ferric nitrate is dissolved in 10mL of pure water, so that the redox component in the electrocatalyst is iron oxide.

[0082] The remaining preparation methods and parameters are consistent with those in Example 1.

[0083] Example 5

[0084] The difference between this embodiment and embodiment 4 is that the ammonium niobate oxalate in step (2) is replaced with ammonium molybdate, so that the acidic component in the electrocatalyst is molybdenum oxide.

[0085] The remaining preparation methods and parameters are consistent with those in Example 4.

[0086] Example 6

[0087] The difference between this embodiment and embodiment 4 is that the ammonium niobate oxalate in step (2) is replaced with ammonium metatungstate, so that the acidic component in the electrocatalyst is tungsten oxide.

[0088] The remaining preparation methods and parameters are consistent with those in Example 4.

[0089] Example 7

[0090] The difference between this embodiment and embodiment 1 is that the ammonium metavanadate solution in step (2) is replaced with copper nitrate solution, that is, 1g of copper nitrate is dissolved in 10mL of pure water, so that the redox component in the electrocatalyst is copper oxide.

[0091] The remaining preparation methods and parameters are consistent with those in Example 1.

[0092] Example 8

[0093] The difference between this embodiment and embodiment 7 is that ammonium niobate in step (2) is replaced with ammonium molybdate, so that the acidic component in the electrocatalyst is molybdenum oxide.

[0094] The remaining preparation methods and parameters are consistent with those in Example 7.

[0095] Example 9

[0096] The difference between this embodiment and embodiment 7 is that the ammonium niobate oxalate in step (2) is replaced with ammonium metatungstate, so that the acidic component in the electrocatalyst is tungsten oxide.

[0097] The remaining preparation methods and parameters are consistent with those in Example 7.

[0098] Example 10

[0099] The difference between this embodiment and embodiment 1 is that the roasting temperature in step (3) is 200°C.

[0100] The remaining preparation methods and parameters are consistent with those in Example 1.

[0101] Example 11

[0102] The difference between this embodiment and embodiment 1 is that the roasting temperature in step (3) is 700°C.

[0103] The remaining preparation methods and parameters are consistent with those in Example 1.

[0104] Comparative Example 1

[0105] The difference between this comparative example and Example 1 is that step (2) does not involve preparing a niobium oxalate ammonium solution, thus ensuring that the electrocatalyst does not contain acidic components.

[0106] The remaining preparation methods and parameters are consistent with those in Example 1.

[0107] Figure 2 This is a schematic diagram of the spherical aberration of the electrocatalyst prepared in this comparative example. As can be seen from the figure, the redox components are embedded in the crystal lattice surface of the support in the form of single atoms.

[0108] Comparative Example 2

[0109] The difference between this comparative example and Example 4 is that step (2) does not involve preparing a niobium oxalate ammonium solution, thus ensuring that the electrocatalyst does not contain acidic components.

[0110] The remaining preparation methods and parameters are consistent with those in Example 4.

[0111] Comparative Example 3

[0112] The difference between this comparative example and Example 7 is that step (2) does not involve preparing a niobium oxalate ammonium solution, thus ensuring that the electrocatalyst does not contain acidic components.

[0113] The remaining preparation methods and parameters are consistent with those in Example 7.

[0114] Comparative Example 4

[0115] The difference between this comparative example and Example 1 is that the amounts of ammonium metavanadate solution and ammonium niobate oxalate solution added were adjusted so that the mass ratio of redox component to acidic component in the electrocatalyst was 1:2.5.

[0116] The remaining preparation methods and parameters are consistent with those in Example 1.

[0117] Comparative Example 5

[0118] The difference between this comparative example and Example 1 is that the amounts of ammonium metavanadate solution and ammonium niobate oxalate solution added were adjusted so that the mass ratio of redox component to acidic component in the electrocatalyst was 1:0.2.

[0119] The remaining preparation methods and parameters are consistent with those in Example 1.

[0120] The types, radii, and atomic sequences of metal ions in the electrocatalysts prepared in the above examples and comparative examples are summarized in Table 1.

[0121] Table 1

[0122]

[0123]

[0124] Performance testing

[0125] The denitration performance of the electrocatalysts prepared in the above examples and comparative examples was tested. The specific test steps are as follows:

[0126] First, a quartz tube was filled with 0.15g of electrocatalyst, and both sides were clamped tightly with conductive copper filters to ensure the catalyst's secure position. Simultaneously, the conductive copper filters were brought into contact with the electrodes, and the two electrodes were connected to both sides of a DC power supply. In regulated voltage mode, the voltage was gradually increased, controlling the voltage range between 1-20V and the power between 1-50W. When the catalytic activity reached its maximum, the voltage was gradually decreased while the temperature of the external thermal field was increased. During this process, a gaseous pollutant containing nitrogen oxides (composition: [NO] = [NH3] = 550ppm, [O2] = 5%, N2 as the balance gas) was introduced, and the temperature of the catalytic oxygen reduction reaction was controlled at 50-500℃, with a mass hourly space velocity of 30000mL / (g·h). The catalyst activity and nitrogen selectivity were then tested.

[0127] The test results are shown in Table 2.

[0128] Table 2

[0129]

[0130]

[0131]

[0132]

[0133] analyze:

[0134] As shown in the table above, this invention introduces a specific ratio of redox components and acidic components embedded in the crystal lattice surface of the support in a single-atom form. The two work synergistically to efficiently match the flowing charge on the surface of the electrocatalyst and achieve full utilization of the unit redox component, thus achieving "two birds with one stone". This allows the electrocatalyst to adapt to the special characteristics of electrically driven removal of atmospheric pollutants, achieving a balance between acidic and redox performance in the ultra-low temperature stage under energized conditions. This enables it to achieve efficient conversion of atmospheric pollutants at ultra-low temperatures and within a wide temperature window, and has advantages such as high low-temperature activity, wide operating temperature window, significant energy-saving effect, high stability, and high applicability.

[0135] As can be seen from Examples 1 and 10-11, if the calcination temperature in step (3) is too low, the atoms of the redox components and acidic components will not be able to be embedded in the lattice surface of the carrier in a single-atom form; if the calcination temperature in step (3) is too high, the lattice structure of the conductive carrier will be damaged.

[0136] As can be seen from Example 1 and Comparative Example 1, Example 4 and Comparative Example 2, and Example 7 and Comparative Example 3, if the electrocatalyst does not contain acidic components, the redox capacity will be much higher than the adsorption capacity of ammonia, and the two cannot achieve the purpose of synergistic cooperation, thereby reducing the removal of nitrogen oxides.

[0137] Based on Examples 1 and Comparative Examples 4-5, if the mass ratio of the redox component to the acidic component is too small, that is, the content of the acidic component is too large, it will result in an excessively strong acidic ability, and the two cannot work together synergistically; if the mass ratio of the redox component to the acidic component is too large, that is, the content of the acidic component is too small, it will result in an excessively strong redox ability of the reaction, and the two cannot work together synergistically.

[0138] The applicant declares that the present invention is illustrated by the above embodiments, but the present invention is not limited to the above process steps, that is, it does not mean that the present invention must rely on the above process steps to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials used in the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. An electrocatalyst, characterized in that, The electrocatalyst includes a support and an active component. The support is a reducible oxide conductive support, and the active component includes a redox component and an acidic component. The active component is embedded in the crystal lattice surface of the support in a single-atom form. The reducible oxide conductive carrier is a tin dioxide-based oxide material doped with heteroelement. The heteroelement includes any one or at least two of F, In, Sb, P, Cl or Te; The redox component is any one or at least two of vanadium pentoxide, iron oxide, or copper oxide. The acidic component is an acidic metal oxide; The acidic metal oxide includes any one or at least two of niobium oxide, tungsten oxide, or molybdenum oxide; The mass ratio of the redox component to the acidic component is 1:(0.5-2); The loading of the redox component on the support is 1-3%; The acidic component is loaded at a rate of 1-6% on the carrier.

2. The electrocatalyst according to claim 1, characterized in that, The reducible oxide conductive carrier includes any one or at least two of fluorine-doped tin dioxide, indium-doped tin dioxide, or antimony-doped tin dioxide.

3. The electrocatalyst according to claim 1, characterized in that, The reducible oxide conductive carrier is antimony-doped tin dioxide.

4. A method for preparing an electrocatalyst as described in any one of claims 1-3, characterized in that, The preparation method includes the following steps: (1) Mix the precursor of the redox component, the precursor of the acidic component and the solvent to obtain a precursor solution of the active component; (2) The precursor solution of the active component and the reducible oxide conductive support are mixed and calcined to obtain the electrocatalyst; The roasting temperature in step (2) is 300-600℃.

5. The preparation method according to claim 4, characterized in that, The precursor of the redox component in step (1) includes nitrate.

6. The preparation method according to claim 5, characterized in that, The nitrate includes any one or at least two of copper nitrate, ferric nitrate, or ammonium metavanadate.

7. The preparation method according to claim 4, characterized in that, The precursor of the acidic component in step (1) includes any one or at least two of ammonium niobate, ammonium metatungstate, or ammonium molybdate.

8. The preparation method according to claim 4, characterized in that, The reducible oxide conductive carrier in step (2) is a heteroelement-doped tin dioxide-based oxide material. The preparation method of the heteroelement-doped tin dioxide-based oxide material includes any one or at least two of the following: chemical coprecipitation, hydrothermal method, solvent method, combustion method, or sol-gel method.

9. The preparation method according to claim 8, characterized in that, The preparation method of the heteroelement-doped tin dioxide-based oxide material is a chemical coprecipitation method.

10. The preparation method according to claim 9, characterized in that, In the chemical coprecipitation method, the sintering temperature is 400-600℃ and the sintering time is 1-8h.

11. The preparation method according to claim 4, characterized in that, The mixing method described in step (2) includes any one or at least two of the following: co-impregnation, hydrothermal method, or solvent method.

12. The preparation method according to claim 4, characterized in that, The mixing method described in step (2) is co-impregnation.

13. The preparation method according to claim 4, characterized in that, The mixing process described in step (2) is accompanied by ultrasound.

14. The preparation method according to claim 4, characterized in that, The roasting time in step (2) is 1-8 hours.

15. The preparation method according to claim 4, characterized in that, The preparation method includes the following steps: (I) A heteroelement-doped tin dioxide-based oxide material is prepared by chemical co-precipitation, wherein the sintering temperature is 400-600℃ and the sintering time is 1-8h, and the heteroelement includes any one or at least two of F, In, Sb, P, Cl or Te; (II) Disperse the precursors of the redox component and the acidic component with loadings of 1-3% and 1-6% respectively in a solvent to obtain a precursor solution of the active component; (III) The precursor solution of the active component and the tin dioxide-based oxide material doped with heteroelement are mixed by co-impregnation method. The mixing process is accompanied by ultrasound, and then calcined at 300-600℃ for 1-8 hours. After calcination, the electrocatalyst is obtained.

16. The application of an electrocatalyst as described in any one of claims 1-3, characterized in that, The electrocatalyst is used for the catalytic reduction and removal of gaseous pollutants; The gaseous pollutants include nitrogen oxides.

17. The application according to claim 16, characterized in that, The catalytic reduction removal of the gaseous pollutants includes the following steps: (a) Apply DC power to both ends of the electrocatalyst to make the electrocatalyst in a conductive state; (b) A gaseous pollutant containing nitrogen oxides is introduced into the container containing the electrocatalyst in the conducting state to carry out a catalytic reduction reaction.

18. The application according to claim 17, characterized in that, The DC power supply described in step (a) has an output power of 1-50W and an output voltage of 1-20V.

19. The application according to claim 17, characterized in that, The temperature of the catalytic reduction reaction is 50-500℃.

20. The application according to claim 17, characterized in that, The temperature of the catalytic reduction reaction is 50-300℃.

21. The application according to claim 17, characterized in that, The composition of the nitrogen oxide-containing gaseous pollutants in step (b) includes: 0-5000 ppm nitrogen oxides, 0-5000 ppm ammonia, 0-20% oxygen by volume, and nitrogen as a balance gas.

22. The application according to claim 17, characterized in that, The mass hourly space velocity (MSV) of the nitrogen oxide-containing gaseous pollutant in step (b) is 0-500000 mL / (h·g).

23. The application according to claim 17, characterized in that, The mass hourly space velocity (MSV) of the nitrogen oxide-containing gaseous pollutant in step (b) is 10,000-200,000 mL / (h·g).

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