A rare earth denitration catalyst, a preparation method and application thereof

Abstract

This invention relates to a rare earth denitrification catalyst, its preparation method, and its application. The rare earth denitrification catalyst comprises rare earth element single atoms and a titanium dioxide-based composite oxide doped with rare earth single atoms. The rare earth element single atoms in this invention exhibit a high adsorption priority for sulfur dioxide, allowing the position and quantity of sulfate to be controlled by the rare earth element single atoms. Furthermore, the hydroxyl groups in the sulfate can enhance the acidity of the catalyst, thereby further improving its redox capacity. The titanium dioxide-based composite oxide can effectively inhibit sulfur dioxide poisoning and further improve the catalyst's denitrification ability in the presence of sulfur dioxide. The rare earth denitrification catalyst of this invention maintains high catalytic activity even in the presence of sulfur dioxide, exhibiting excellent denitrification and sulfur resistance performance.

Description

Technical Field

[0001] This invention relates to the field of environmental catalyst technology, specifically to a denitrification catalyst, its preparation method, and its application, and more particularly to a rare earth denitrification catalyst, its preparation method, and its application. Background Technology

[0002] Nitrogen oxides (NO) x Nitrogen oxides (NOx) are a major source of air pollution, primarily originating from the combustion of fossil fuels. Excessive emissions can lead to environmental and climate problems such as acid rain, photochemical smog, and global warming. Traditional denitrification technologies utilize ammonia selective catalytic reduction (NH3-SCR) with V2O5-WO3 / TiO2 or its modified forms as catalysts, typically operating at temperatures between 300℃ and 400℃. However, the toxicity of V2O5 in these catalysts makes their recovery and treatment a bottleneck for development. Catalysts using cerium oxide (CeO2) and modified cerium oxide as active components have attracted widespread attention from researchers due to their excellent low-to-medium temperature catalytic activity, high nitrogen selectivity, and environmental friendliness.

[0003] Currently, in practical applications, SCR denitrification catalysts used for boiler flue gas treatment encounter the problem of catalyst deactivation due to sulfur dioxide poisoning. This is because the coal ash produced during boiler combustion contains a certain amount of sulfur dioxide gas. This gas adsorbs onto the catalyst surface and reacts with cerium-based active sites to form cerium sulfate, which covers the catalyst surface, reducing the number of exposed active sites. Simultaneously, under the influence of water, sulfur dioxide gas also reacts directly with ammonia to form ammonium sulfate or ammonium bisulfate, causing the catalyst to lose its redox capacity, thus triggering catalyst poisoning.

[0004] CN102416320A discloses a denitrification catalyst, which is composed of the following components in parts by weight: 75-85 parts titanium dioxide; 10-12 parts tungsten trioxide; 3-6 parts silicon dioxide; 2-3 parts vanadium pentoxide; 3-6 parts kapok pulp; 2-7 parts glass fiber; and 2-3 parts stearic acid. The components are mixed according to the specified parts by weight, stirred evenly, and then sequentially subjected to aging, pre-extrusion, secondary aging, extrusion molding, primary drying, secondary drying, high-temperature calcination, and finished product trimming before packaging to obtain the finished catalyst. CN107737588A discloses a denitrification catalyst, whose raw materials, by weight, are 35-45 parts titanium dioxide, 2-5 parts antimony oxide, 10-20 parts glass fiber, 1-3 parts vanadium pentoxide, 3-6 parts molybdenum oxide, and 3-6 parts tungsten oxide.

[0005] The denitrification catalysts described in the above schemes struggle to maintain catalytic activity at both high and low temperatures, and sulfur dioxide poisoning leads to a sharp decline in catalyst activity. Therefore, improving the denitrification performance of denitrification catalysts in the presence of sulfur dioxide is crucial for saving flue gas purification costs in the coal-fired industry and improving waste gas treatment efficiency. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a rare earth denitrification catalyst, its preparation method, and its application. The rare earth denitrification catalyst of this invention exhibits a high adsorption priority for sulfur dioxide by its rare earth element single atoms. Furthermore, the position and quantity of sulfate can be controlled by the rare earth element single atoms, and the acidity of the catalyst can be increased by utilizing the hydroxyl groups in the sulfate, thereby further enhancing the catalyst's redox capacity. Its titanium dioxide-based composite oxide can effectively inhibit sulfur dioxide poisoning and further improve the catalyst's denitrification ability in the presence of sulfur dioxide. The rare earth denitrification catalyst of this invention maintains high catalytic activity even in the presence of sulfur dioxide, exhibiting excellent denitrification performance and sulfur resistance.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a rare earth denitrification catalyst, the rare earth denitrification catalyst comprising rare earth element single atoms and rare earth single atom-doped titanium dioxide-based composite oxides.

[0009] The rare earth denitrification catalyst of this invention exhibits a high adsorption priority for sulfur dioxide by its rare earth element single atoms. This allows for the regulation of the position and quantity of sulfates via rare earth element single atoms, and the use of hydroxyl groups in the sulfates to enhance the catalyst's acidity, further improving its redox capacity. Its titanium dioxide-based composite oxide effectively inhibits sulfur dioxide poisoning, further enhancing the catalyst's denitrification ability in the presence of sulfur dioxide. The rare earth denitrification catalyst of this invention maintains high catalytic activity even in the presence of sulfur dioxide, demonstrating excellent denitrification and sulfur resistance performance.

[0010] Preferably, the titanium dioxide-based composite oxide has the composition ABTiO. x Where A is a rare earth metal element and B is a transition metal element, 1≤x≤2, for example, x can be 1, 1.2, 1.5, 1.8 or 2, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0011] The titanium dioxide-based composite oxide in the rare earth denitration catalyst of this invention contains rare earth metal elements and transition metal elements. These two elements can interact to form adjacent redox-acidic sites. Therefore, in the absence of sulfur dioxide, the rate of the NH3-SCR reaction according to the LH mechanism is effectively increased. Furthermore, titanium can stabilize the rare earth metal elements and transition metal elements, improving the stability of the titanium dioxide-based composite oxide. In the presence of sulfur dioxide, neither the transition metal elements nor titanium can easily form their corresponding metal sulfates, thus inhibiting sulfur dioxide poisoning from a material formation perspective. Simultaneously, the introduction of rare earth single atoms further enhances the catalyst's redox capacity. In the presence of sulfur dioxide, rare earth single atoms can control the position and quantity of sulfate formation, effectively utilizing the additional bronsted acidic sites introduced by sulfates to the catalyst surface. This increases the catalyst's adsorption capacity for NH3, at which point the rate-determining step on the catalyst surface transforms into an activated dehydrogenation reaction between NH3 and the redox sites, followed by a rapid reaction with gaseous NO according to the ER mechanism, further improving the catalyst's denitration performance.

[0012] Preferably, the rare earth metal element includes any one or a combination of at least two of cerium, neodymium, samarium, europium, yttrium, dysprosium, ytterbium, lanthanum, or praseodymium. Typical but non-limiting combinations include the combination of cerium and neodymium, or the combination of ytterbium, lanthanum, and praseodymium.

[0013] Preferably, the transition metal element B includes any one or a combination of at least two of tungsten, molybdenum, niobium, chromium, iron, cobalt, nickel, or manganese. Typical but non-limiting combinations include a combination of tungsten and molybdenum, or a combination of cobalt, nickel, and manganese.

[0014] Preferably, the rare earth single atom includes any one or a combination of at least two of cerium, neodymium, samarium, europium, yttrium, dysprosium, ytterbium, lanthanum, or praseodymium. Typical but non-limiting combinations include the combination of cerium and neodymium, or the combination of ytterbium, lanthanum, and praseodymium.

[0015] Preferably, the molar ratio of the rare earth single atom and the titanium dioxide-based composite oxide is (0.005-0.05):1, for example, it can be 0.005:1, 0.01:1, 0.02:1, 0.03:1, 0.04:1 or 0.05:1, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0016] Preferably, in the titanium dioxide-based composite oxide, the molar ratio of rare earth dopant element A to titanium element is (0.01-0.05):1, for example, it can be 0.01:1, 0.02:1, 0.03:1, 0.04:1 or 0.05:1, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0017] This invention, by further controlling the molar ratio of rare earth dopant elements to titanium in the titanium dioxide-based composite oxide, is beneficial to further improve the catalytic activity of the rare earth denitration catalyst under high and low temperature conditions. Within a preferred range, the prepared rare earth denitration catalyst exhibits further enhanced redox capabilities, as well as improved denitration and sulfur resistance.

[0018] Preferably, in the titanium dioxide-based composite oxide, the molar ratio of transition metal element B to titanium element is (0.01-0.3):1, for example, it can be 0.01:1, 0.05:1, 0.1:1, 0.2:1 or 0.3:1, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0019] In a second aspect, the present invention provides a method for preparing a denitrification catalyst as described in the first aspect. The preparation method includes the following steps: mixing a rare earth metal source, a transition metal source, a titanium source and acetic acid to obtain a mixed solution, stirring to obtain a gel precursor, and then drying and calcining it in sequence to obtain the rare earth denitrification catalyst.

[0020] Preferably, the mixing method includes mixing a rare earth metal source solution and a transition metal source solution and adding acetic acid to obtain a mixture of the two solutions, and then adding a titanium source solution dropwise to the mixture of the two solutions to obtain the mixed solution.

[0021] This invention uses acetic acid to connect rare earth metal sources, transition metal sources, and titanium sources together to form a gel. The ionic radius of rare earth metal elements is larger than that of titanium ions, so only a portion of them can enter the crystal structure of titanium dioxide. Therefore, some rare earth metal sources will be converted into rare earth single atoms during the calcination process. The ionic radius of transition metal elements is comparable to that of titanium ions, so all of them can enter the crystal structure of titanium dioxide, resulting in titanium dioxide doped with rare earth metal elements and transition metal elements, and finally obtaining the rare earth denitration catalyst described in this invention.

[0022] Preferably, the solvent of the rare earth metal source solution includes ethanol.

[0023] Preferably, the solvent of the transition metal source solution includes deionized water.

[0024] Preferably, the solvent of the titanium source solution includes ethanol.

[0025] The denitration catalyst provided by this invention is simple and easy to operate. It involves dissolving three metal sources in different solvents, generating a gel in the system through slow hydrolysis with acetic acid, and then drying and calcining the gel to synthesize the catalyst. The preparation method of this invention is low in cost, fast, and has a high success rate.

[0026] The rare earth metal source includes any one or a combination of at least two of cerium nitrate, neodymium nitrate, samarium nitrate, europium nitrate, yttrium nitrate, dysprosium nitrate, ytterbium nitrate, lanthanum nitrate, or praseodymium nitrate. Typical but non-limiting combinations include a combination of cerium nitrate and neodymium nitrate, or a combination of ytterbium nitrate, lanthanum nitrate, and praseodymium nitrate.

[0027] Preferably, the transition metal source includes any one or a combination of at least two of ammonium metatungstate, ammonium molybdate, ammonium niobate oxalate, chromium nitrate, ferric nitrate, cobalt nitrate, nickel nitrate, or manganese nitrate. Typical but non-limiting combinations include a combination of ammonium metatungstate and ammonium molybdate, or a combination of cobalt nitrate, nickel nitrate, and manganese nitrate.

[0028] Preferably, the titanium source includes any one or a combination of at least two of tetrabutyl titanate, isopropyl titanate, or di(triethanolamine) titanate. Typical but non-limiting combinations include a combination of tetrabutyl titanate and isopropyl titanate, or a combination of tetrabutyl titanate, isopropyl titanate, and di(triethanolamine) titanate.

[0029] This invention utilizes a specific organic titanium source to prepare the rare-earth denitration catalyst. The specific organic titanium source can be converted into titanium dioxide during calcination, and it facilitates the entry of rare-earth and transition metal elements into the titanium lattice. If an inorganic titanium source is used, the entry of rare-earth and transition metal elements into the titanium lattice requires high energy and stringent preparation conditions.

[0030] Preferably, the sum of the molar amounts of the rare earth metal source, the transition metal source, and the titanium source is M, and the molar ratio of acetic acid to M is (1-5):1, for example, it can be 1:1, 2:1, 3:1, 4:1 or 5:1, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0031] Preferably, the stirring speed is 500 r / min to 1000 r / min, for example, it can be 500 r / min, 600 r / min, 800 r / min, 900 r / min or 1000 r / min, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0032] This invention, by further controlling the stirring speed, can prevent the solution from splashing onto the container wall, causing uneven element distribution and preventing the formation of single atoms, and can also prevent element agglomeration. In other words, by controlling the stirring speed, this invention can further improve the uniformity and dispersibility of the gel precursor, thereby further improving the denitrification performance and sulfur resistance of the rare earth denitrification catalyst.

[0033] Preferably, the dripping rate is 2 mL / min to 10 mL / min, for example, it can be 2 mL / min, 4 mL / min, 6 mL / min, 8 mL / min or 10 mL / min, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0034] This invention, by further controlling the dropping rate, can avoid uneven element distribution, which is detrimental to the formation of single atoms, and can also prevent phase separation. In other words, by controlling the dropping rate, this invention can further improve the uniformity and consistency of the gel precursor, thereby further improving the denitrification performance and sulfur resistance of the rare earth denitrification catalyst.

[0035] Preferably, after the gel precursor is obtained by stirring, it is allowed to stand before drying.

[0036] Preferably, the settling time is 12h-72h, for example, it can be 12h, 24h, 36h, 48h, 60h or 72h, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0037] Preferably, the drying and heat preservation temperature is 80℃-105℃, for example, it can be 80℃, 85℃, 90℃, 95℃, 100℃ or 105℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0038] Preferably, the drying and heat preservation time is 24h-48h, for example, it can be 24h, 30h, 36h, 42h or 48h, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0039] Preferably, the calcination holding temperature is 400℃-600℃, for example, it can be 400℃, 450℃, 500℃, 550℃ or 600℃, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0040] This invention, by further controlling the calcination holding temperature, can avoid agglomeration and the formation of rare earth elements, as well as prevent a decrease in crystallinity and incomplete crystal growth, which would otherwise lead to reduced catalytic performance. In other words, by controlling the calcination holding temperature, this invention can further regulate the crystallinity and uniformity of the rare earth denitrification catalyst, thereby further improving its denitrification performance and sulfur resistance.

[0041] Preferably, the heating rate of the calcination is 1℃ / min-10℃ / min, for example, it can be 1℃ / min, 3℃ / min, 5℃ / min, 7℃ / min, 9℃ / min or 10℃ / min, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0042] Preferably, the calcination holding time is 3h-10h, for example, it can be 3h, 5h, 7h, 9h or 10h, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0043] As a preferred technical solution of the present invention, the preparation method includes the following steps:

[0044] (1) Dissolve the rare earth metal source in ethanol and the transition metal source in deionized water respectively. Then mix the two solutions and add acetic acid to obtain a mixture of the two solutions.

[0045] (2) After dissolving the titanium source in ethanol, an ethanol solution of the titanium source is obtained. Under stirring, a mixture of the two solutions is added dropwise to the ethanol solution of the titanium source, and stirring is continued to obtain a gel precursor. The stirring speed is 500 r / min-1000 r / min, and the dropwise addition speed is 2 mL / min-10 mL / min.

[0046] (3) The gel precursor is subjected to static standing, drying and calcination in sequence to obtain the rare earth denitration catalyst. The static standing time is 12h-72h, the drying temperature is 80℃-105℃ and the holding time is 24h-48h, the calcination temperature is 400℃-600℃, the heating rate is 1℃ / min-10℃ / min and the holding time is 3h-10h.

[0047] Thirdly, the present invention provides an application of the rare earth denitrification catalyst as described in the first aspect, wherein the rare earth denitrification catalyst is applied to the selective catalytic reduction of nitrogen oxides by ammonia.

[0048] Preferably, the operating temperature of the ammonia selective catalytic reduction of nitrogen oxides reaction is 200℃-550℃, for example, it can be 200℃, 300℃, 400℃, 500℃ or 550℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 250℃-500℃.

[0049] Preferably, the rare earth denitration catalyst is activated and pretreated before being applied to the selective catalytic reduction of nitrogen oxides by ammonia.

[0050] This invention enables the rapid construction of surface oxygen vacancy defects on the catalyst surface through activation pretreatment of the rare earth denitration catalyst, and can also effectively improve the acidity of the catalyst, thereby further improving the denitration performance and sulfur resistance of the rare earth denitration catalyst.

[0051] Preferably, the holding temperature for the activation pretreatment is 300℃-500℃, for example, it can be 300℃, 350℃, 400℃, 450℃ or 500℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0052] Preferably, the heating rate of the activation pretreatment is 3℃ / min-7℃ / min, for example, it can be 3℃ / min, 4℃ / min, 5℃ / min, 6℃ / min or 7℃ / min, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0053] Preferably, during the activation pretreatment process, the gas flow rate per unit weight of catalyst per unit time is 1 mL / (g·min) to 5 mL / (g·min), for example, it can be 1 mL / (g·min), 2 mL / (g·min), 3 mL / (g·min), 4 mL / (g·min) or 5 mL / (g·min), but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0054] Preferably, the holding time for the activation pretreatment is 5h-20h, for example, it can be 5h, 10h, 15h or 20h, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0055] Preferably, the environmental atmosphere of the activation pretreatment includes any one or a combination of at least two of ammonia, oxygen, sulfur dioxide, hydrogen, water vapor, or argon. Typical but non-limiting combinations include a combination of ammonia and oxygen, or a combination of hydrogen, water vapor, and argon. Preferably, it is a mixture of ammonia, oxygen, sulfur dioxide, and argon.

[0056] During the activation stage, the lattice oxygen on the catalyst surface is used to form NH4HSO4. After this substance decomposes, it produces gases such as water, ammonia, and sulfur trioxide. Therefore, the lattice oxygen cannot be regenerated after it leaves, resulting in an increase in oxygen vacancy defects on the catalyst surface. This significantly improves the activation ability of oxygen in the reaction atmosphere, leading to an enhancement of the catalyst's redox capacity. This effectively promotes the activation and dehydrogenation process of NH3 and improves the denitrification performance.

[0057] Preferably, the mass concentration of ammonia in the pretreatment atmosphere is 300ppm-1000ppm, for example, it can be 300ppm, 400ppm, 500ppm, 600ppm, 700ppm, 800ppm, 900ppm or 1000ppm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0058] Preferably, the mass concentration of oxygen in the pretreatment atmosphere is 3%-10%, for example, it can be 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0059] Preferably, the mass concentration of sulfur dioxide in the pretreatment atmosphere is 100ppm-500ppm, for example, it can be 100ppm, 200ppm, 300ppm, 400ppm or 500ppm, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0060] Preferably, the mass concentration ratio of ammonia to sulfur dioxide in the pretreatment atmosphere is (2-3):1, for example, it can be 2:1, 2.3:1, 2.5:1, 2.8:1 or 3:1, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0061] Fourthly, the present invention provides a denitrification reactor, the denitrification reactor comprising the rare earth denitrification catalyst described in the first aspect.

[0062] Fifthly, the present invention provides a denitrification device comprising the denitrification reactor described in the fourth aspect, wherein the denitrification device comprises a mobile source gas denitrification device and / or a stationary source gas denitrification device.

[0063] Preferably, the mobile source gas denitrification device includes any one of a diesel engine, a gas turbine, or an aircraft engine.

[0064] Preferably, the stationary source gas denitrification device includes an industrial kiln and / or a roasting kiln.

[0065] Compared with the prior art, the present invention has at least the following beneficial effects:

[0066] (1) In the rare earth denitration catalyst of the present invention, the rare earth single-atom and titanium dioxide-based composite oxide can effectively enhance the acidity and redox ability of the catalyst, and promote the adsorption of NH3 and NO by the catalyst. Titanium dioxide-based composite oxide ABTiO x The presence of asymmetric oxygen vacancies such as AO-Ti, BO-Ti, and AOB can enhance NO production. xThe rare earth denitrification catalyst of this invention exhibits high adsorption capacity and dehydrogenation capacity for NH3. Furthermore, in the presence of sulfur dioxide, the rare earth denitrification catalyst of this invention accumulates relatively little sulfate on its surface, thus preventing sulfur dioxide poisoning. Instead, the small amount of sulfate on the surface further enhances the acidity of the catalyst, promoting NH3 adsorption and effectively improving the denitrification performance of the catalyst.

[0067] (2) The rare earth denitration catalyst of the present invention is simple and easy to operate, has mild synthesis conditions, high yield, high success rate, and does not contain heavy metals such as vanadium-based substances, which is relatively environmentally friendly.

[0068] (3) The activation pretreatment method of the rare earth denitrification catalyst of the present invention can further improve the denitrification performance and sulfur resistance performance of the rare earth denitrification catalyst.

[0069] (4) The rare earth denitrification catalyst of the present invention is used for the selective catalytic reduction of nitrogen oxides by ammonia and can cover an ultra-wide temperature range of 250℃-500℃. At the same time, the rare earth denitrification catalyst has excellent denitrification performance and sulfur resistance performance. Attached Figure Description

[0070] Figure 1 This is the XRD pattern of the rare earth denitrification catalyst described in Example 1 of this invention;

[0071] Figure 2 This is the synchrotron radiation X-ray extended absorption spectrum of Ce element in the rare earth denitration catalyst described in Example 1 of this invention;

[0072] Figure 3 This is a wavelet transform analysis of the Ce element in the rare earth denitration catalyst described in Example 1 of the present invention;

[0073] Figure 4 This is a TEM image of the rare earth denitrification catalyst described in Example 1 of the present invention, with a scale bar of 100 nm.

[0074] Figure 5 This is an AC-TEM image of the rare earth denitrification catalyst described in Example 1 of this invention, with a scale bar of 2 nm.

[0075] Figure 6 This is a TEM image of the rare earth denitrification catalyst described in Example 2 of the present invention, with a scale bar of 50 nm. Detailed Implementation

[0076] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, the following examples are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims.

[0077] In the following application example, the simulated flue gas contains 500 ppm NH3, 500 ppm NO, 5% O2, 250 ppm SO2, and the balance gas is nitrogen.

[0078] Example 1

[0079] This embodiment provides a rare earth denitration catalyst, which comprises rare earth Ce single atoms and titanium dioxide-based composite oxide Ce. 0.01 Mo 0.05 The molar ratio of the rare earth single atom and the titanium dioxide-based composite oxide in TiO is 0.009:1.

[0080] The preparation method of the rare earth denitration catalyst includes the following steps:

[0081] (1) Dissolve 0.2931g of cerium nitrate hexahydrate in 19.7mL of anhydrous ethanol, and dissolve 0.596g of ammonium molybdate tetrahydrate in 7.3mL of deionized water. Then mix the two solutions and add 11.6mL of acetic acid to obtain a mixed solution of the two solutions.

[0082] (2) Dissolve 22.97 mL of tetrabutyl titanate in 20 mL of ethanol. While stirring, add the mixture of the two solutions dropwise to the ethanol solution of tetrabutyl titanate. Continue stirring to obtain a gel precursor. The stirring speed is 700 r / min and the dropwise addition speed is 5 mL / min.

[0083] (3) The gel precursor is subjected to static, drying and calcination in sequence to obtain the rare earth denitration catalyst. The static time is 24h, the drying temperature is 105℃ and the holding time is 24h, the calcination temperature is 500℃, the heating rate is 5℃ / min and the holding time is 4h.

[0084] Figure 1 The image shows the XRD pattern of the rare earth denitration catalyst described in Example 1 of this invention. It can be seen from the image that the diffraction peaks of the catalyst are in good agreement with the standard diffraction peaks of TiO2. No other phases such as CeO2 or MoO3 were found, indicating that Ce and Mo elements have been successfully doped into the TiO2 lattice. Figure 2 This is the synchrotron radiation X-ray extended absorption spectrum of Ce element in the rare earth denitration catalyst described in Example 1 of this invention. Figure 3 The wavelet transform analysis of Ce element in the rare earth denitrification catalyst described in Example 1 of this invention shows that only Ce-O and Ce-Ti coordination structures exist in the coordination structure of Ce element, and there is no Ce-Ce coordination, indicating that Ce element exists in the TiO2 lattice in a highly dispersed single-atom form. Figure 4This is a TEM image of the rare earth denitrification catalyst described in Example 1 of the present invention. The scale bar is 100 nm. As can be seen from the image, the rare earth denitrification catalyst has uniform particle size and good dispersibility. Figure 5 This is an AC-TEM image of the rare earth denitrification catalyst described in Example 1 of the present invention, with a scale bar of 2 nm. As can be seen from the image, the rare earth denitrification catalyst includes rare earth single atoms.

[0085] Example 2

[0086] This embodiment provides a rare earth denitration catalyst, which comprises rare earth La single atoms and titanium dioxide-based composite oxide La. 0.05 W 0.3 The molar ratio of the rare earth single atom and the titanium dioxide-based composite oxide in TiO2 is 0.038:1.

[0087] The preparation method of the rare earth denitration catalyst includes the following steps:

[0088] (1) Dissolve 1.4665g of lanthanum nitrate hexahydrate in 19.7mL of anhydrous ethanol, and dissolve 5.020g of ammonium metatungstate in 36.5mL of deionized water. Then mix the two solutions and add 34.8mL of acetic acid to obtain a mixed solution of the two solutions.

[0089] (2) Dissolve 22.97 mL of isopropyl titanate in 20 mL of ethanol. While stirring, add the mixture of the two solutions dropwise to the ethanol solution of tetrabutyl titanate. Continue stirring to obtain a gel precursor. The stirring speed is 500 r / min and the dropwise addition speed is 2 mL / min.

[0090] (3) The gel precursor is subjected to static, drying and calcination in sequence to obtain the rare earth denitration catalyst. The static time is 12h, the drying temperature is 80℃ and the holding time is 48h, the calcination temperature is 400℃, the heating rate is 1℃ / min and the holding time is 10h.

[0091] Figure 5 This is a TEM image of the rare earth denitrification catalyst described in Example 2 of the present invention. The scale bar is 50 nm. As can be seen from the image, the rare earth denitrification catalyst has uniform particle size and good dispersibility.

[0092] Example 3

[0093] This embodiment provides a rare earth denitration catalyst, which comprises rare earth Nd single atoms and titanium dioxide-based composite oxide Nd. 0.01 Co 0.01 TiO 1.5The molar ratio of the rare earth single atom and the titanium dioxide-based composite oxide is 0.01:1.

[0094] (1) Dissolve 0.2958g of neodymium nitrate hexahydrate in 19.7mL of anhydrous ethanol, and dissolve 0.1235g of cobalt nitrate in 7.3mL of deionized water. Then mix the two solutions and add 11.6mL of acetic acid to obtain a mixed solution of the two solutions.

[0095] (2) Dissolve 22.97 mL of di(triethanolamine) titanate diisopropyl ester in 20 mL of ethanol. While stirring, add the mixture of the two solutions dropwise to the ethanol solution of tetrabutyl titanate. Continue stirring to obtain a gel precursor. The stirring speed is 1000 r / min and the dropwise addition speed is 10 mL / min.

[0096] (3) The gel precursor is subjected to static, drying and calcination in sequence to obtain the rare earth denitration catalyst. The static time is 72h, the drying temperature is 105℃ and the holding time is 24h, the calcination temperature is 600℃, the heating rate is 10℃ / min and the holding time is 3h.

[0097] Example 4

[0098] The only difference between this embodiment and Example 1 is that, except that in step (1), 0.2931g of cerium nitrate hexahydrate is replaced with 0.2933g of lanthanum nitrate hexahydrate, and the titanium dioxide-based composite oxide of the rare earth denitration catalyst prepared is La. 0.01 Mo 0.05 Except for TiO, everything else is the same as in Example 1.

[0099] Example 5

[0100] The only difference between this embodiment and Example 1 is that, except that in step (1), 0.2931g of cerium nitrate hexahydrate is replaced with 0.2958g of neodymium nitrate hexahydrate, and the titanium dioxide-based composite oxide of the rare earth denitration catalyst prepared is Nd 0.01 Mo 0.05 Except for TiO, everything else is the same as in Example 1.

[0101] Example 6

[0102] The only difference between this embodiment and Example 1 is that, except that in step (1), 0.596g of ammonium molybdate tetrahydrate is replaced with 0.837g of ammonium metatungstate, and the titanium dioxide-based composite oxide of the rare earth denitration catalyst prepared is Ce. 0.01 W 0.05 Except for TiO, everything else is the same as in Example 1.

[0103] Example 7

[0104] The only difference between this embodiment and Example 1 is that, except that in step (1), 0.596g of ammonium molybdate tetrahydrate is replaced with 1.081g of ammonium niobate oxalate hydrate, and the titanium dioxide-based composite oxide of the rare earth denitration catalyst prepared is Ce. 0.01 Nb 0.05 Except for TiO, everything else is the same as in Example 1.

[0105] Example 8

[0106] The only difference between this embodiment and Example 1 is that, except that in step (1), 0.596g of ammonium molybdate tetrahydrate is replaced with 1.351g of chromium nitrate nonahydrate, and the titanium dioxide-based composite oxide of the rare earth denitration catalyst prepared is Ce. 0.01 Cr 0.05 Except for TiO, everything else is the same as in Example 1.

[0107] Example 9

[0108] The only difference between this embodiment and Example 1 is that, except that in step (1), 0.2931g of cerium nitrate hexahydrate is replaced with 0.1466g of cerium nitrate hexahydrate, and the titanium dioxide-based composite oxide of the rare earth denitration catalyst prepared is Ce. 0.005 Mo 0.05 Except for TiO, everything else is the same as in Example 1.

[0109] Example 10

[0110] The only difference between this embodiment and Example 1 is that, except that in step (1), 0.2931g of cerium nitrate hexahydrate is replaced with 2.931g of cerium nitrate hexahydrate, and the titanium dioxide-based composite oxide of the rare earth denitration catalyst prepared is Ce. 0.1 Mo 0.05 Except for TiO, everything else is the same as in Example 1.

[0111] Example 11

[0112] The only difference between this embodiment and Example 1 is that, except that in step (1), 0.596g of ammonium molybdate tetrahydrate is replaced with 5.960g of ammonium molybdate tetrahydrate, and the titanium dioxide-based composite oxide of the rare earth denitration catalyst prepared is Ce. 0.01 Mo 0.5 Except for TiO, everything else is the same as in Example 1.

[0113] Example 12

[0114] The only difference between this embodiment and Example 1 is that, except that in step (1), 0.596g of ammonium molybdate tetrahydrate is replaced with 0.0596g of ammonium molybdate tetrahydrate, and the titanium dioxide-based composite oxide of the rare earth denitration catalyst prepared is Ce. 0.01 Mo0.005 Except for TiO, everything else is the same as in Example 1.

[0115] Example 13

[0116] The only difference between this embodiment and embodiment 1 is that, except that the dropping speed in step (2) is 1 mL / min, everything else is the same as in embodiment 1.

[0117] Example 14

[0118] The only difference between this embodiment and embodiment 1 is that, except that the dropping speed in step (2) is 11 mL / min, everything else is the same as in embodiment 1.

[0119] Example 15

[0120] The only difference between this embodiment and embodiment 1 is that, except for the stirring speed in step (2) being 400 r / min, everything else is the same as in embodiment 1.

[0121] Example 16

[0122] The only difference between this embodiment and embodiment 1 is that, except for the stirring speed in step (2) being 1100 r / min, everything else is the same as in embodiment 1.

[0123] Example 17

[0124] The only difference between this embodiment and embodiment 1 is that, except that the holding temperature for the roasting in step (3) is 350°C, everything else is the same as in embodiment 1.

[0125] Example 18

[0126] The only difference between this embodiment and embodiment 1 is that, except that the holding temperature for the roasting in step (3) is 650°C, everything else is the same as in embodiment 1.

[0127] Comparative Example 1

[0128] The only difference between this comparative example and Example 1 is that, except that 0.2931g of cerium nitrate hexahydrate in step (1) is replaced with 0.057g of sodium nitrate hexahydrate, everything else is the same as in Example 1.

[0129] Comparative Example 2

[0130] The only difference between this comparative example and Example 1 is that, except that 22.97 mL of tetrabutyl titanate in step (2) is replaced with 5.405 g of titanium dioxide powder, everything else is the same as in Example 1.

[0131] Comparative Example 3

[0132] The only difference between this comparative example and Example 1 is that, except that the mixture of the two solutions described in step (1) does not include ammonium molybdate solution, everything else is the same as in Example 1.

[0133] Comparative Example 4

[0134] The only difference between this comparative example and Example 1 is that, except that the mixture of the two solutions in step (1) does not include cerium nitrate solution, the other two aspects are the same as in Example 1.

[0135] Application Example 1-1

[0136] This application example provides an application of a rare earth denitration catalyst, which is used in the selective catalytic reduction of nitrogen oxides by ammonia:

[0137] The rare earth denitrification catalyst described in Example 1 was placed in a tubular furnace. A mixed gas containing 500 ppm NH3, 250 ppm SO2, 5% O2, and argon was introduced into the furnace to activate and pretreat the rare earth denitrification catalyst. Simulated flue gas and simulated flue gas without SO2 were then introduced. The ammonia selective catalytic reduction of nitrogen oxides was carried out at 250°C, 300°C, 350°C, and 400°C. The holding temperature of the activation and pretreatment was 400°C, the holding time of the activation and pretreatment was 10 h, the heating rate of the activation and pretreatment was 5°C / min, the gas flow rate per unit weight of catalyst per unit time during the pretreatment was 3 mL / (g·min), and the operating temperature of the ammonia selective catalytic reduction of nitrogen oxides was 300°C.

[0138] Application Example 1-2

[0139] This application example provides an application of a rare earth denitration catalyst, which is used in the selective catalytic reduction of nitrogen oxides by ammonia:

[0140] The rare earth denitrification catalyst described in Example 1 was placed in a tube furnace. A mixed gas containing 300 ppm NH3, 100 ppm SO2, 3% O2, and argon was introduced into the furnace to activate and pretreat the rare earth denitrification catalyst. Simulated flue gas and simulated flue gas without SO2 were then introduced. The ammonia selective catalytic reduction of nitrogen oxides was carried out at 250°C, 300°C, 350°C, and 400°C. The holding temperature of the activation and pretreatment was 300°C, the holding time of the activation and pretreatment was 20 h, the heating rate of the activation and pretreatment was 3°C / min, and the gas flow rate per unit weight of catalyst per unit time during the pretreatment was 1 mL / (g·min). The operating temperature of the ammonia selective catalytic reduction of nitrogen oxides was 200°C.

[0141] Application Examples 1-3

[0142] This application example provides an application of a rare earth denitration catalyst, which is used in the selective catalytic reduction of nitrogen oxides by ammonia:

[0143] The rare earth denitrification catalyst described in Example 1 was placed in a tubular furnace. A mixed gas containing 1000 ppm NH3, 500 ppm SO2, 10% O2, and argon was introduced into the furnace to activate and pretreat the rare earth denitrification catalyst. Simulated flue gas and simulated flue gas without SO2 were then introduced. The ammonia selective catalytic reduction of nitrogen oxides was carried out at 250°C, 300°C, 350°C, and 400°C. The holding temperature of the activation and pretreatment was 500°C, the holding time of the activation and pretreatment was 5 h, the heating rate of the activation and pretreatment was 7°C / min, the gas flow rate per unit weight of catalyst per unit time during the pretreatment was 5 mL / (g·min), and the operating temperature of the ammonia selective catalytic reduction of nitrogen oxides was 550°C.

[0144] Application Example 2

[0145] The only difference between this application example and application example 1-1 is that, except for the rare earth denitrification catalyst described in example 2, everything else is the same as in application example 1-1.

[0146] Application Example 3

[0147] The only difference between this application example and application example 1-1 is that, except for the rare earth denitrification catalyst described in Example 3, everything else is the same as in application example 1-1.

[0148] Application Example 4

[0149] The only difference between this application example and application example 1-1 is that, except for the rare earth denitrification catalyst described in Example 4, everything else is the same as in application example 1-1.

[0150] Application Example 5

[0151] The only difference between this application example and application example 1-1 is that, except for the rare earth denitrification catalyst described in Example 5, everything else is the same as in application example 1-1.

[0152] Application Example 6

[0153] The only difference between this application example and application example 1-1 is that, except for the rare earth denitrification catalyst described in Example 6, everything else is the same as in application example 1-1.

[0154] Application Example 7

[0155] The only difference between this application example and application example 1-1 is that, except for the rare earth denitrification catalyst described in Example 7, everything else is the same as in application example 1-1.

[0156] Application Example 8

[0157] The only difference between this application example and application example 1-1 is that, except for the rare earth denitrification catalyst described in Example 8, everything else is the same as in application example 1-1.

[0158] Application Example 9

[0159] The only difference between this application example and application example 1-1 is that, except for the rare earth denitrification catalyst described in Example 9, everything else is the same as in application example 1-1.

[0160] Application Example 10

[0161] The only difference between this application example and application example 1-1 is that, except for the rare earth denitrification catalyst described in Example 10, everything else is the same as in application example 1-1.

[0162] Application Example 11

[0163] The only difference between this application example and application example 1-1 is that, except for the rare earth denitrification catalyst described in Example 11, everything else is the same as in application example 1-1.

[0164] Application Example 12

[0165] The only difference between this application example and application example 1-1 is that, except for the rare earth denitrification catalyst described in Example 12, everything else is the same as in application example 1-1.

[0166] Application Example 13

[0167] The only difference between this application example and application example 1-1 is that, except for the rare earth denitrification catalyst described in Example 13, everything else is the same as in application example 1-1.

[0168] Application Example 14

[0169] The only difference between this application example and application example 1-1 is that, except for the rare earth denitrification catalyst described in Example 14, everything else is the same as in application example 1-1.

[0170] Application Example 15

[0171] The only difference between this application example and application example 1-1 is that, except for the rare earth denitrification catalyst described in Example 15, everything else is the same as in application example 1-1.

[0172] Application Example 16

[0173] The only difference between this application example and application example 1-1 is that, except for the rare earth denitrification catalyst described in Example 16, everything else is the same as in application example 1-1.

[0174] Application Example 17

[0175] The only difference between this application example and application example 1-1 is that, except for the rare earth denitrification catalyst described in Example 17, everything else is the same as in application example 1-1.

[0176] Application Example 18

[0177] The only difference between this application example and application example 1-1 is that, except for the rare earth denitrification catalyst described in Example 18, everything else is the same as in application example 1-1.

[0178] Application Example 19

[0179] The only difference between this application example and application example 1-1 is that, except for the lack of activation pretreatment of the rare earth denitration catalyst, everything else is the same as in application example 1-1.

[0180] Application Example 20

[0181] The only difference between this application example and application example 1-1 is that, except for the introduction of a mixture of 500ppm NH3, 250ppm SO2 and argon, everything else is the same as in application example 1-1.

[0182] Application Example 21

[0183] The only difference between this application example and application example 1-1 is that, except for the introduction of a mixture of 250ppm SO2 and argon, everything else is the same as in application example 1-1.

[0184] Application Example 22

[0185] The only difference between this application example and application example 1-1 is that, except that the holding temperature for the activation pretreatment is 250°C, everything else is the same as application example 1-1.

[0186] Application Example 23

[0187] The only difference between this application example and application example 1-1 is that, except that the holding temperature for the activation pretreatment is 550°C, everything else is the same as application example 1-1.

[0188] Comparative Application Example 1

[0189] The only difference between this application example and application example 1-1 is that, except for the rare earth denitrification catalyst described in Comparative Example 1, everything else is the same as in application example 1-1.

[0190] Comparative Application Example 2

[0191] The only difference between this application example and application example 1-1 is that, except for the rare earth denitrification catalyst described in comparative example 2, everything else is the same as in application example 1-1.

[0192] Comparative Application Example 3

[0193] The only difference between this application example and application example 1-1 is that, except for the rare earth denitrification catalyst described in comparative example 3, everything else is the same as in application example 1-1.

[0194] Comparative Application Example 4

[0195] The only difference between this application example and application example 1-1 is that, except for the rare earth denitrification catalyst described in comparative example 4, everything else is the same as in application example 1-1.

[0196] Test methods

[0197] The nitrogen oxide content at the catalyst outlet was analyzed using a Thermo Fisher IGS Analyzer infrared flue gas analyzer for the products obtained at different reaction temperatures in Application Examples 1-1-23 and Comparative Example 1-4, and the analysis results are recorded in Table 1.

[0198] Table 1

[0199]

[0200]

[0201]

[0202]

[0203] The test results show that:

[0204] (1) As can be seen from Application Examples 1-1-23 and Comparative Example 1-4, the rare earth denitrification catalyst of the present invention has rare earth single atoms that can adsorb sulfur dioxide, thereby increasing the acidity of the catalyst and further improving its redox ability; its titanium dioxide-based composite oxide can effectively inhibit sulfur dioxide poisoning and further improve the denitrification ability of the catalyst in the presence of sulfur dioxide. The rare earth denitrification catalyst of the present invention can still have high catalytic activity in the presence of sulfur dioxide.

[0205] (2) As can be seen from Application Examples 1-1 and 4-5, by further controlling the type of rare earth metal source, the present invention can further improve the denitrification performance and sulfur resistance performance of the catalyst. When rare earth elements are doped into the lattice of titanium dioxide, it is beneficial to further release the lattice oxygen and further reduce the row layer of oxygen vacancies, thereby improving the redox ability of the catalyst.

[0206] (3) As can be seen from Application Examples 1-1 and Application Examples 6-8, the present invention can further improve the denitrification performance and sulfur resistance performance of the catalyst by further controlling the type of transition metal source, and effectively promote the activation of NH3 by further increasing the amount of oxygen adsorbed on the catalyst surface.

[0207] (4) As can be seen from Application Examples 1-1 and 9-12, the present invention can further improve the denitrification performance and sulfur resistance performance of the catalyst by further adjusting the molar ratio of rare earth metal source and transition metal source to titanium source.

[0208] (5) As can be seen from Application Examples 1-1 and Application Examples 13-16, by further controlling the dropping speed and stirring speed, the present invention can further improve the uniformity and dispersibility of the gel precursor, thereby further improving the denitrification performance and sulfur resistance performance of the catalyst.

[0209] (6) As can be seen from Application Examples 1-1 and 17-18, the present invention can further improve the crystallinity and dispersibility of the catalyst by further controlling the holding temperature of the calcination temperature, thereby further improving the denitrification performance and sulfur resistance performance of the catalyst.

[0210] (7) As can be seen from Application Examples 1-1 and 19-21, the present invention can further improve the denitrification performance and sulfur resistance performance of the catalyst by further regulating the environmental atmosphere of the activation pretreatment.

[0211] (8) As can be seen from Application Examples 1-1 and 22-23, the present invention can further improve the denitrification performance and sulfur resistance performance of the catalyst by further controlling the heat preservation temperature of the activation pretreatment.

[0212] (9) As can be seen from Application Example 1-1 and Comparative Application Example 1-Comparative Application Example 4, the present invention, by forming rare earth single atom and titanium dioxide-based composite oxide, is beneficial to further improve the denitrification performance and sulfur resistance performance of the catalyst.

[0213] In summary, the rare earth denitrification catalyst of this invention has rare earth single atoms that can adsorb sulfur dioxide, thereby increasing the catalyst's acidity and further enhancing its redox capacity. Its titanium dioxide-based composite oxide can effectively inhibit sulfur dioxide poisoning and further improve the catalyst's denitrification ability in the presence of sulfur dioxide. The rare earth denitrification catalyst of this invention maintains high catalytic activity even in the presence of sulfur dioxide. Furthermore, after activation pretreatment, the rare earth denitrification catalyst of this invention exhibits an increased number of redox sites, significantly enhancing its activation ability for NH3, thus demonstrating superior denitrification performance and sulfur resistance.

[0214] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. The application of a rare earth denitration catalyst in the selective catalytic reduction of nitrogen oxides by ammonia, characterized in that, The rare earth denitrification catalyst includes rare earth single atoms and rare earth single atom-doped titanium dioxide-based composite oxides. The molar ratio of the rare earth single atom and the titanium dioxide-based composite oxide is (0.005-0.05):1; The titanium dioxide-based composite oxide has the composition ABTiO. x Where A is a rare earth metal element, B is a transition metal element, and 1≤x≤2; The molar ratio of the transition metal element to titanium element is (0.01-0.3):1; The rare earth denitration catalyst is prepared by a method comprising the following steps: After mixing rare earth metal source, transition metal source, titanium source and acetic acid to obtain a mixed solution, the mixture is stirred to obtain a gel precursor, which is then dried and calcined in sequence to obtain the rare earth denitration catalyst. The mixing method includes mixing a rare earth metal source solution and a transition metal source solution and adding acetic acid to obtain a mixture of the two solutions, and then adding a titanium source solution dropwise to the mixture of the two solutions to obtain the mixed solution. The stirring speed is 500 r / min-1000 r / min; The dripping rate is 2 mL / min - 10 mL / min; The rare earth metal element A includes any one or a combination of at least two of cerium, neodymium, samarium, europium, yttrium, dysprosium, ytterbium, lanthanum, or praseodymium; The transition metal element B includes any one or a combination of at least two of tungsten, molybdenum, niobium, chromium, iron, cobalt, nickel, or manganese; The roasting temperature is 400℃-600℃.

2. The application according to claim 1, characterized in that, The rare earth single atom includes any one or a combination of at least two of cerium, neodymium, samarium, europium, yttrium, dysprosium, ytterbium, lanthanum, or praseodymium.

3. The application according to claim 1, characterized in that, In the titanium dioxide-based composite oxide, the molar ratio of rare earth dopant element A to titanium element is (0.01-0.05):

1.

4. The application according to claim 1, characterized in that, The rare earth metal source includes any one or a combination of at least two of cerium nitrate, neodymium nitrate, samarium nitrate, europium nitrate, yttrium nitrate, dysprosium nitrate, ytterbium nitrate, lanthanum nitrate, or praseodymium nitrate.

5. The application according to claim 1, characterized in that, The transition metal source includes any one or a combination of at least two of the following: ammonium metatungstate, ammonium molybdate, ammonium niobate oxalate, chromium nitrate, ferric nitrate, cobalt nitrate, nickel nitrate, or manganese nitrate.

6. The application according to claim 1, characterized in that, The titanium source includes any one or a combination of at least two of tetrabutyl titanate, isopropyl titanate, or di(triethanolamine) titanate.

7. The application according to claim 1, characterized in that, The drying process is carried out at a temperature of 80℃-105℃.

8. The application according to claim 1, characterized in that, The drying and heat preservation time is 24h-48h.

9. The application according to claim 1, characterized in that, The roasting time is 3-10 hours.

10. The application according to claim 1, characterized in that, The operating temperature for the ammonia selective catalytic reduction of nitrogen oxides reaction is 200℃-550℃.

11. The application according to claim 1, characterized in that, The operating temperature for the ammonia selective catalytic reduction of nitrogen oxides reaction is 250℃-500℃.

12. The application according to claim 1, characterized in that, The rare earth denitrification catalyst is activated and pretreated before being applied to the selective catalytic reduction of nitrogen oxides by ammonia.

13. The application according to claim 12, characterized in that, The holding temperature for the activation pretreatment is 300℃-500℃.

14. The application according to claim 12, characterized in that, The activation pretreatment environment includes any one or a combination of at least two of ammonia, oxygen, sulfur dioxide, hydrogen, water vapor, or argon.

15. The application according to claim 14, characterized in that, The activation pretreatment environment is a mixture of ammonia, oxygen, sulfur dioxide, and argon.

16. A denitrification reactor, characterized in that, The denitrification reactor includes the rare earth denitrification catalyst described in claim 1.

17. A denitrification apparatus comprising the denitrification reactor of claim 16, characterized in that, The denitrification device includes a mobile source gas denitrification device and / or a stationary source gas denitrification device.

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