Rare earth denitration catalyst as well as preparation method and application thereof

Abstract

The invention relates to a rare earth denitration catalyst as well as a preparation method and application thereof. The rare earth denitration catalyst comprises rare earth element single atoms and a titanium dioxide-based composite oxide doped with the rare earth element single atoms. According to the rare earth denitration catalyst disclosed by the invention, the rare earth element monatomic has a relatively high adsorption priority on sulfur dioxide, so that the position and the quantity of sulfate can be regulated and controlled through the rare earth element monatomic, the acidity of the catalyst is improved by utilizing hydroxyl in the sulfate, and the oxidation-reduction capability of the catalyst can be further improved; the titanium dioxide-based composite oxide can effectively inhibit poisoning of sulfur dioxide, and can further improve the denitration capability of the catalyst in the presence of sulfur dioxide. The rare earth denitration catalyst provided by the invention can still have relatively high catalytic activity in the presence of sulfur dioxide, and has excellent denitration performance and sulfur resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of environmental protection catalysts, and relates to a denitration catalyst and a preparation method and application thereof, and in particular to a rare earth denitration catalyst and a preparation method and application thereof. Background Art

[0002] Nitrogen oxides (NO x ) is the main source of air pollution, mainly from the combustion of fossil fuels. Excessive emissions can cause environmental and climate problems such as acid rain, photochemical smog or global warming. Traditional denitrification technology uses ammonia selective catalytic reduction (NH3-SCR) method, with V2O5-WO3 / TiO2 or its modified substances as catalysts, and the operating temperature is usually 300℃-400℃. However, the V2O5 in this catalyst is toxic, which makes its recovery and treatment a bottleneck in development. Catalysts with cerium oxide (CeO2) and modified cerium oxide as active components have attracted widespread attention from researchers because of their good medium and low temperature catalytic activity, high nitrogen selectivity and environmental protection characteristics.

[0003] At present, in practical applications, when SCR denitrification catalysts are used for boiler flue gas treatment, they will encounter the problem of sulfur dioxide poisoning leading to catalyst deactivation. This is because the coal ash produced during the boiler combustion process contains a certain amount of sulfur dioxide gas, which will be adsorbed on the catalyst surface and react with the cerium-based active sites to generate cerium sulfate and cover the catalyst surface, which reduces the number of active sites exposed. At the same time, under the action of water, sulfur dioxide gas will also directly react with ammonia to generate substances such as ammonium sulfate or ammonium bisulfate, causing the catalyst to lose its redox ability, thereby causing catalyst poisoning.

[0004] CN102416320A discloses a denitration catalyst, which is composed of the following components in parts by weight: 75-85 parts of titanium dioxide; 10-12 parts of tungsten trioxide; 3-6 parts of silicon dioxide; 2-3 parts of vanadium pentoxide; 3-6 parts of kapok pulp; 2-7 parts of glass fiber; 2-3 parts of stearic acid; each component is mixed and stirred evenly after being proportioned by weight, and then aged, pre-extruded, secondary aged, extruded, dried once, dried twice, calcined at high temperature, and finished product trimmed in sequence, and then the finished catalyst can be packaged. CN107737588A discloses a denitration catalyst, whose raw materials are 35-45 parts of titanium dioxide, 2-5 parts of antimony oxide, 10-20 parts of glass fiber, 1-3 parts of vanadium pentoxide, 3-6 parts of molybdenum oxide, and 3-6 parts of tungsten oxide in parts by weight.

[0005] The denitration catalyst described in the above scheme is difficult to take into account both high-temperature and low-temperature catalytic activity, and after being poisoned by sulfur dioxide, the activity of the catalyst will drop sharply. Therefore, improving the denitration performance of the denitration catalyst in the presence of sulfur dioxide is very important for saving the flue gas purification cost of the coal-fired industry and improving the waste gas treatment efficiency. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a rare earth denitration catalyst and its preparation method and application. The rare earth denitration catalyst of the present invention has a high adsorption priority of a single rare earth atom to sulfur dioxide, and can regulate the position and amount of sulfate by a single rare earth atom, and use the hydroxyl group in the sulfate to improve the acidity of the catalyst, and can also further improve the redox ability of the catalyst; its titanium dioxide-based composite oxide can effectively inhibit the poisoning of sulfur dioxide, and can also further improve the denitration ability of the catalyst in the presence of sulfur dioxide. The rare earth denitration catalyst of the present invention can still have a high catalytic activity in the presence of sulfur dioxide, and has excellent denitration performance and sulfur resistance.

[0007] To achieve this object, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a rare earth denitration catalyst, which comprises a rare earth element single atom and a titanium dioxide-based composite oxide doped with a rare earth single atom.

[0009] The rare earth denitration catalyst of the present invention has a high adsorption priority of the rare earth element single atom to sulfur dioxide, and can regulate the position and amount of sulfate by the rare earth element single atom, and use the hydroxyl group in the sulfate to improve the acidity of the catalyst, and can also further improve the redox ability of the catalyst; the titanium dioxide-based composite oxide can effectively inhibit the poisoning of sulfur dioxide, and can also further improve the denitration ability of the catalyst in the presence of sulfur dioxide. The rare earth denitration catalyst of the present invention can still have a high catalytic activity in the presence of sulfur dioxide, and has excellent denitration performance and sulfur resistance.

[0010] Preferably, the composition of the titanium dioxide-based composite oxide is ABTiO x , wherein A is a rare earth metal element, 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, and other unlisted values ​​within the numerical range are also applicable.

[0011] The titanium dioxide-based composite oxide in the rare earth denitration catalyst of the present invention contains rare earth metal elements and transition metal elements, and these two elements can interact with each other to form adjacent redox-acidic sites. Therefore, in the absence of sulfur dioxide, the rate of the NH3-SCR reaction occurring according to the LH mechanism is effectively improved, and the titanium element can stabilize the rare earth metal elements and the transition metal elements, thereby improving the stability of the titanium dioxide-based composite oxide. In the reaction atmosphere in the presence of sulfur dioxide, it is difficult for both the transition metal elements and the titanium element to form corresponding metal sulfates, thereby suppressing the poisoning of sulfur dioxide from the perspective of material generation. At the same time, the introduction of rare earth single atoms can further enhance the redox ability of the catalyst, and in the presence of sulfur dioxide, the rare earth single atoms can control the position and amount of sulfate formation, thereby effectively utilizing the additional Bronsted acid sites introduced by sulfate to the catalyst surface, increasing the catalyst's adsorption capacity for NH3, and at this time, the catalyst surface reaction rate-controlling step is transformed into an activation dehydrogenation reaction occurring between NH3 and the redox site, and then directly reacts rapidly with gas-phase NO according to the ER mechanism, further improving the denitration performance of the catalyst.

[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 a combination of cerium and neodymium, or a combination of ytterbium, lanthanum and praseodymium.

[0013] Preferably, the transition metal element B includes any one of tungsten, molybdenum, niobium, chromium, iron, cobalt, nickel or manganese, or a combination of at least two thereof. 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 atom includes any one of cerium, neodymium, samarium, europium, yttrium, dysprosium, ytterbium, lanthanum or praseodymium, or a combination of at least two of them. Typical but non-limiting combinations include a combination of cerium and neodymium, or a 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, and other unlisted values ​​within the numerical range are also applicable.

[0016] Preferably, in the titanium dioxide-based composite oxide, the molar ratio of the rare earth doping element A to the 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, and other unlisted values ​​within the numerical range are also applicable.

[0017] The present invention further regulates the molar ratio of the rare earth doping element and the titanium element in the titanium dioxide-based composite oxide, which is conducive to further improving 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 has a further enhanced redox ability, and its denitration performance and sulfur resistance are further improved.

[0018] Preferably, in the titanium dioxide-based composite oxide, the molar ratio of the transition metal element B to the 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, and other unlisted values ​​within the numerical range are also applicable.

[0019] In a second aspect, the present invention provides a method for preparing a denitration catalyst as described in the first aspect, the preparation method comprising 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 in sequence to obtain the rare earth denitration catalyst.

[0020] Preferably, the mixing method comprises 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 dropwise adding a titanium source solution to the mixture of the two solutions to obtain the mixed solution.

[0021] The present invention connects a rare earth metal source, a transition metal source and a titanium source together through acetic acid to form a gel. The ionic radius of the rare earth metal element is larger than that of the titanium ion, and only a part of the rare earth metal element can enter the lattice structure of titanium dioxide. Therefore, a part of the rare earth metal source is converted into rare earth single atoms during the roasting process. The ionic radius of the transition metal element is equivalent to that of the titanium ion, and all of the transition metal element can enter the lattice structure of titanium dioxide, thereby obtaining titanium dioxide doped with rare earth metal elements and transition metal elements, and finally obtaining the rare earth denitration catalyst of the present invention.

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

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

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

[0025] The preparation method of the denitration catalyst provided by the present invention is simple and easy to operate. The three metal sources are dissolved in different solvents respectively, a gel is generated in the system by slow hydrolysis of acetic acid, and the gel is subsequently dried and calcined to synthesize the catalyst. The preparation method of the present invention has low cost, high speed and high success rate.

[0026] The rare earth metal source includes any one of cerium nitrate, neodymium nitrate, samarium nitrate, europium nitrate, yttrium nitrate, dysprosium nitrate, ytterbium nitrate, lanthanum nitrate or praseodymium nitrate, or a combination of at least two of them. 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 of ammonium metatungstate, ammonium molybdate, ammonium niobate oxalate, chromium nitrate, iron nitrate, cobalt nitrate, nickel nitrate or manganese nitrate, or a combination of at least two thereof. 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 of tetrabutyl titanate, isopropyl titanate or di(triethanolamine)diisopropyl titanate, or a combination of at least two of them. 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)diisopropyl titanate.

[0029] The present invention adopts a specific organic titanium source to prepare the rare earth denitration catalyst. The specific organic titanium source can be converted into titanium dioxide during the roasting process, and is conducive to the entry of rare earth metal elements and transition metal elements into the titanium lattice. If an inorganic titanium source is used, the rare earth metal elements and transition metal elements enter the titanium lattice, which requires high energy and harsh 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 the 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, and other unlisted values ​​within the numerical range are also applicable.

[0031] Preferably, the stirring speed is 500 r / min-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, and other unlisted values ​​within the numerical range are also applicable.

[0032] The present invention can avoid the solution splashing to the container wall, causing uneven element distribution and failure to form single atoms, and can also avoid element agglomeration by further regulating the stirring speed. That is, the present invention can further improve the uniformity and dispersibility of the gel precursor by regulating the stirring speed, thereby further improving the denitration performance and sulfur resistance of the rare earth denitration catalyst.

[0033] Preferably, the dropping speed is 2 mL / min-10 mL / min, for example, 2 mL / min, 4 mL / min, 6 mL / min, 8 mL / min or 10 mL / min, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0034] The present invention can avoid uneven element distribution, which is not conducive to the formation of single atoms, and can also avoid phase separation by further regulating the dripping speed. That is, the present invention can further improve the uniformity and consistency of the gel precursor by regulating the dripping speed, thereby further improving the denitration performance and sulfur resistance of the rare earth denitration catalyst.

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

[0036] Preferably, the standing time is 12h-72h, for example, 12h, 24h, 36h, 48h, 60h or 72h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

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

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

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

[0040] The present invention can avoid agglomeration and the formation of rare earth elements by further regulating the heat preservation temperature of calcination, and can also avoid the decrease of crystal crystallinity and incomplete growth of crystal structure, which leads to the decrease of catalytic performance. That is, the present invention can further regulate the crystallinity and uniformity of the rare earth denitration catalyst by regulating the heat preservation temperature of calcination, so as to further improve the denitration performance and sulfur resistance of the rare earth denitration catalyst.

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

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

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

[0044] (1) After a rare earth metal source is dissolved in ethanol and a transition metal source is dissolved in deionized water, the two solutions are mixed and acetic acid is added to obtain a mixture of the two solutions.

[0045] (2) Dissolving the titanium source in ethanol to obtain an ethanol solution of the titanium source, and adding the mixture of the two solutions to the ethanol solution of the titanium source under stirring, and continuing to stir to obtain a gel precursor, wherein the stirring speed is 500 r / min-1000 r / min, and the dropping speed is 2 mL / min-10 mL / min.

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

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

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

[0049] Preferably, the rare earth denitration catalyst is subjected to activation pretreatment before being used in the selective catalytic reduction of nitrogen oxides by ammonia.

[0050] The present invention can realize rapid construction of surface oxygen vacancy defects on the surface of the catalyst by performing activation pretreatment on 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 of the activation pretreatment is 300°C-500°C, for example, 300°C, 350°C, 400°C, 450°C or 500°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0052] Preferably, the heating rate of the activation pretreatment is 3°C / min-7°C / min, for example, 3°C / min, 4°C / min, 5°C / min, 6°C / min or 7°C / min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0053] Preferably, during the activation pretreatment process, the gas flow rate per unit time on the unit weight of the catalyst is 1 mL / (g·min)-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, and other unlisted values ​​within the numerical range are equally applicable.

[0054] Preferably, the holding time of the activation pretreatment is 5 h-20 h, for example, 5 h, 10 h, 15 h or 20 h, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0055] Preferably, the ambient atmosphere of the activation pretreatment includes any one of ammonia, oxygen, sulfur dioxide, hydrogen, water vapor or argon, or a combination of at least two of them. Typical but non-limiting combinations include a combination of ammonia and oxygen, or a combination of hydrogen, water vapor and argon, preferably 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, which produces gases such as water, ammonia and sulfur trioxide after decomposition. Therefore, the lattice oxygen cannot be regenerated after leaving, resulting in an increase in oxygen vacancy defects on the catalyst surface. The ability to activate oxygen in the reaction atmosphere is significantly improved, resulting in an increase in the catalyst's redox ability, which 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, and other unlisted values ​​within the numerical 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, and other unlisted values ​​within the numerical range are also applicable.

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

[0061] In a fourth aspect, the present invention provides a denitration reactor, comprising the rare earth denitration catalyst described in the first aspect.

[0062] In a fifth aspect, the present invention provides a denitration device comprising the denitration reactor described in the fourth aspect, wherein the denitration device comprises a mobile source gas denitration device and / or a fixed source gas denitration 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 fixed 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 improve 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 in the xIn addition, when sulfur dioxide exists, the rare earth denitration catalyst of the present invention has less sulfate accumulation on the surface, which will not cause sulfur dioxide poisoning. Instead, the catalyst acidity can be further improved by using a small amount of sulfate on the surface to promote the adsorption of NH3, thereby effectively improving the denitration performance of the catalyst.

[0067] (2) The preparation method of the rare earth denitrification catalyst described in the present invention is simple and easy to operate, the synthesis conditions are mild, the yield is large, the success rate is high, and it does not contain heavy metal substances such as vanadium-based substances, and is relatively environmentally friendly.

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

[0069] (4) The rare earth denitration 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°C-500°C. At the same time, the rare earth denitration catalyst has excellent denitration performance and sulfur resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] Figure 1 is the XRD spectrum of the rare earth denitration catalyst described in Example 1 of the present invention;

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

[0072] Figure 3 The 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 denitration catalyst described in Example 1 of the present invention, with a scale of 100 nm;

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

[0075] Figure 6 This is a TEM image of the rare earth denitration catalyst described in Example 2 of the present invention, with a scale size of 50 nm. DETAILED DESCRIPTION

[0076] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and through specific implementation methods. However, the following examples are only 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 shall be subject to the claims.

[0077] In the following application example, the simulated flue gas contains NH3 500ppm, NO 500ppm, O2 5%, SO2250ppm, and the balance gas is nitrogen.

[0078] Example 1

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

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

[0081] (1) 0.2931 g of cerium nitrate hexahydrate was dissolved in 19.7 mL of anhydrous ethanol, and 0.596 g of ammonium molybdate tetrahydrate was dissolved in 7.3 mL of deionized water. The two solutions were then mixed, and 11.6 mL of acetic acid was added to obtain a mixed solution of the two solutions.

[0082] (2) Dissolve 22.97 mL of tetrabutyl titanate in 20 mL of ethanol. Add the mixed solution of the two solutions to the ethanol solution of tetrabutyl titanate under stirring, and continue stirring to obtain a gel precursor. The stirring speed is 700 r / min and the dropping speed is 5 mL / min.

[0083] (3) The gel precursor is allowed to stand, dried and calcined in sequence to obtain the rare earth denitration catalyst, wherein the standing time is 24 hours, the drying insulation temperature is 105°C, the insulation time is 24 hours, the calcination insulation temperature is 500°C, the heating rate is 5°C / min, and the insulation time is 4 hours.

[0084] Figure 1 This is the XRD spectrum of the rare earth denitrification catalyst described in Example 1 of the present invention. It can be found from the figure that the diffraction peak of the catalyst is consistent with the standard diffraction peak of TiO2, and no other phases such as CeO2 or MoO3 are found, indicating that Ce and Mo elements have been successfully doped into the TiO2 lattice. Figure 2 is the synchrotron radiation X-ray expanded absorption spectrum of the Ce element in the rare earth denitration catalyst described in Example 1 of the present invention, Figure 3 This is the wavelet transform analysis of the Ce element in the rare earth deNOx catalyst described in Example 1 of the present invention. From the figure, it can be found that the coordination structure of the Ce element only has Ce-O and Ce-Ti coordination, and there is no Ce-Ce coordination, indicating that the Ce element exists in the TiO2 lattice in the form of highly dispersed single atoms. Figure 4This is a TEM image of the rare earth denitration catalyst according to Example 1 of the present invention. The scale size is 100 nm. It can be seen from the image that the particles of the rare earth denitration catalyst are uniform in size and have good dispersibility. Figure 5 This is an AC-TEM image of the rare earth denitration catalyst according to Example 1 of the present invention. The scale size is 2 nm. It can be seen from the image that the rare earth denitration catalyst includes rare earth single atoms.

[0085] Example 2

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

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

[0088] (1) 1.4665 g of lanthanum nitrate hexahydrate was dissolved in 19.7 mL of anhydrous ethanol, and 5.020 g of ammonium metatungstate was dissolved in 36.5 mL of deionized water. The two solutions were then mixed, and 34.8 mL of acetic acid was added to obtain a mixed solution of the two solutions.

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

[0090] (3) The gel precursor is allowed to stand, dried and calcined in sequence to obtain the rare earth denitration catalyst, wherein the standing time is 12 hours, the drying insulation temperature is 80°C, the insulation time is 48 hours, the calcination insulation temperature is 400°C, the heating rate is 1°C / min, and the insulation time is 10 hours.

[0091] Figure 5 This is a TEM image of the rare earth denitration catalyst according to Example 2 of the present invention, with a scale of 50 nm. It can be seen from the image that the particles of the rare earth denitration catalyst are uniform in size and have good dispersibility.

[0092] Example 3

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

[0094] (1) 0.2958 g of neodymium nitrate hexahydrate was dissolved in 19.7 mL of anhydrous ethanol, and 0.1235 g of cobalt nitrate was dissolved in 7.3 mL of deionized water. The two solutions were then mixed, and 11.6 mL of acetic acid was added to obtain a mixed solution of the two solutions.

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

[0096] (3) The gel precursor is allowed to stand, dried and calcined in sequence to obtain the rare earth denitration catalyst, wherein the standing time is 72 hours, the drying insulation temperature is 105°C, the insulation time is 24 hours, the calcination insulation temperature is 600°C, the heating rate is 10°C / min, and the insulation time is 3 hours.

[0097] Example 4

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

[0099] Example 5

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

[0101] Example 6

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

[0103] Example 7

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

[0105] Example 8

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

[0107] Example 9

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

[0109] Example 10

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

[0111] Embodiment 11

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

[0113] Example 12

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

[0117] Embodiment 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, the rest is the same as embodiment 1.

[0119] Embodiment 15

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

[0121] Example 16

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

[0123] Embodiment 17

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

[0125] Embodiment 18

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

[0127] Comparative Example 1

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

[0129] Comparative Example 2

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

[0131] Comparative Example 3

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

[0133] Comparative Example 4

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

[0135] Application Example 1-1

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

[0137] The rare earth denitration catalyst described in Example 1 is placed in a tubular furnace, and a mixed gas containing 500ppm NH3, 250ppm SO2, 5% O2 and argon balance is introduced into the furnace. After the rare earth denitration catalyst is activated and pretreated, simulated flue gas and simulated flue gas without SO2 are introduced respectively, and ammonia selective catalytic reduction of nitrogen oxides is carried out at 250°C, 300°C, 350°C and 400°C. The holding temperature of the activation pretreatment is 400°C, the holding time of the activation pretreatment is 10h, the heating rate of the activation pretreatment is 5°C / min, and during the pretreatment process, the gas flow rate per unit time on the unit weight of the catalyst is 3mL / (g·min), and the operating temperature of the ammonia selective catalytic reduction of nitrogen oxides is 300°C.

[0138] Application Example 1-2

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

[0140] The rare earth denitration catalyst described in Example 1 is placed in a tubular furnace, and a mixed gas containing 300ppm NH3, 100ppm SO2, 3% O2 ​​and argon balance is introduced into the furnace. After the rare earth denitration catalyst is activated and pretreated, simulated flue gas and simulated flue gas without SO2 are introduced respectively, and ammonia selective catalytic reduction of nitrogen oxides is carried out at 250°C, 300°C, 350°C and 400°C. The holding temperature of the activation pretreatment is 300°C, the holding time of the activation pretreatment is 20h, the heating rate of the activation pretreatment is 3°C / min, and during the pretreatment process, the gas flow rate per unit time on the unit weight of the catalyst is 1mL / (g·min). The operating temperature of the ammonia selective catalytic reduction of nitrogen oxides is 200°C.

[0141] Application Examples 1-3

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

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

[0144] Application Example 2

[0145] The only difference between this application example and application example 1-1 is that, except for using the rare earth denitration catalyst described in Example 2, the rest is the same as 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 using the rare earth denitration catalyst described in Example 3, the rest is the same as 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 using the rare earth denitration catalyst described in Example 4, the rest is the same as 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 using the rare earth denitration catalyst described in Example 5, the rest is the same as 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 using the rare earth denitration catalyst described in Example 6, the rest is the same as 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 using the rare earth denitration catalyst described in Example 7, the rest is the same as 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 using the rare earth denitration catalyst described in Example 8, the rest is the same as 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 using the rare earth denitration catalyst described in Example 9, the rest is the same as 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 using the rare earth denitration catalyst described in Example 10, the rest is the same as 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 using the rare earth denitration catalyst described in Example 11, the rest is the same as 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 using the rare earth denitration catalyst described in Example 12, the rest is the same as 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 using the rare earth denitration catalyst described in Example 13, the rest is the same as 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 using the rare earth denitration catalyst described in Example 14, the rest is the same as 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 using the rare earth denitration catalyst described in Example 15, the rest is the same as 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 using the rare earth denitration catalyst described in Example 16, the rest is the same as 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 using the rare earth denitration catalyst described in Example 17, the rest is the same as 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 using the rare earth denitration catalyst described in Example 18, the rest is the same as application example 1-1.

[0178] Application Example 19

[0179] The difference between this application example and application example 1-1 is that, except that the rare earth denitration catalyst is not pre-activated, the rest is the same as application example 1-1.

[0180] Application Example 20

[0181] The difference between this application example and application example 1-1 is that, except for the introduction of a mixed gas of 500ppm NH3, 250ppm SO2 and argon, the rest is the same as application example 1-1.

[0182] Application Example 21

[0183] The difference between this application example and application example 1-1 is that, except for the introduction of a mixed gas of 250 ppm SO2 and argon, the rest is the same as application example 1-1.

[0184] Application Example 22

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

[0186] Application Example 23

[0187] The difference between this application example and application example 1-1 is that, except for the holding temperature of the activation pretreatment being 550° C., the rest 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 using the rare earth denitration catalyst described in comparative example 1, the rest is the same as 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 using the rare earth denitration catalyst described in comparative example 2, the rest is the same as 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 using the rare earth denitration catalyst described in comparative example 3, the rest is the same as 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 using the rare earth denitration catalyst described in comparative example 4, the rest is the same as application example 1-1.

[0196] Test Method

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

[0198] Table 1

[0199]

[0200]

[0201]

[0202]

[0203] The test results show that:

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

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

[0206] (3) It can be seen from Application Examples 1-1 and 6 to 8 that the present invention can further improve the denitrification performance and sulfur resistance of the catalyst by further regulating 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) It can be seen from Application Examples 1-1 and 9 to 12 that the present invention can further improve the denitrification performance and sulfur resistance of the catalyst by further regulating the molar ratio of the rare earth metal source and the transition metal source to the titanium source.

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

[0209] (6) It can be seen from Application Example 1-1 and Application Example 17-Application Example 18 that the present invention is beneficial to further improve the crystallinity and dispersibility of the catalyst by further regulating the insulation temperature of the calcination temperature, thereby further improving the denitrification performance and sulfur resistance of the catalyst.

[0210] (7) It can be seen from Application Example 1-1 and Application Example 19 to Application Example 21 that the present invention is beneficial to further improve the denitrification performance and sulfur resistance of the catalyst by further regulating the environmental atmosphere of the activation pretreatment.

[0211] (8) It can be seen from Application Example 1-1 and Application Example 22-Application Example 23 that the present invention is beneficial to further improve the denitrification performance and sulfur resistance of the catalyst by further regulating the insulation temperature of the activation pretreatment.

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

[0213] In summary, the rare earth denitration catalyst of the present invention has a single rare earth atom that can adsorb sulfur dioxide, thereby increasing the acidity of the catalyst and further increasing the redox ability of the catalyst; its titanium dioxide-based composite oxide can effectively inhibit poisoning by sulfur dioxide and further increase the denitration ability of the catalyst in the presence of sulfur dioxide. The rare earth denitration catalyst of the present invention can still have a high catalytic activity in the presence of sulfur dioxide. In addition, after the rare earth denitration catalyst of the present invention is activated and pretreated, the redox sites on the catalyst are further increased, and the activation ability for NH3 is also significantly improved, so it has more excellent denitration performance and sulfur resistance.

[0214] The applicant declares that the above is only a specific implementation mode 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 thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A rare earth denitration catalyst, characterized in that: The rare earth denitration catalyst comprises rare earth single atoms and rare earth single atom-doped titanium dioxide-based composite oxides.

2. The rare earth denitration catalyst according to claim 1, characterized in that: The composition of the titanium dioxide-based composite oxide is ABTiO x , where A is a rare earth metal element, B is a transition metal element, 1≤x≤2; Preferably, 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; 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; Preferably, the rare earth single atom includes any one of cerium, neodymium, samarium, europium, yttrium, dysprosium, ytterbium, lanthanum or praseodymium, or a combination of at least two thereof.

3. The rare earth denitration catalyst according to claim 1 or 2, characterized in that: The molar ratio of the rare earth single atom to the titanium dioxide-based composite oxide is (0.005-0.05):1; Preferably, in the titanium dioxide-based composite oxide, the molar ratio of the rare earth doping element A to the titanium element is (0.01-0.05):

1.

4. A method for preparing the rare earth denitration catalyst according to any one of claims 1 to 3, characterized in that: The preparation method comprises the following steps: A rare earth metal source, a transition metal source, a titanium source and acetic acid are mixed to obtain a mixed solution, which is then stirred to obtain a gel precursor, which is then dried and calcined in sequence to obtain the rare earth denitration catalyst.

5. The preparation method according to claim 4, characterized in that: The mixing method comprises 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 dropping a titanium source solution into the mixture of the two solutions to obtain the mixed solution; Preferably, the rare earth metal source comprises any one of cerium nitrate, neodymium nitrate, samarium nitrate, europium nitrate, yttrium nitrate, dysprosium nitrate, ytterbium nitrate, lanthanum nitrate or praseodymium nitrate, or a combination of at least two thereof; 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, iron nitrate, cobalt nitrate, nickel nitrate or manganese nitrate; Preferably, the titanium source includes any one of tetrabutyl titanate, isopropyl titanate or di(triethanolamine) diisopropyl titanate, or a combination of at least two thereof.

6. The preparation method according to claim 5, characterized in that: The stirring speed is 500r / min-1000r / min; Preferably, the dripping speed is 2mL / min-10mL / min; Preferably, the drying insulation temperature is 80°C-105°C; Preferably, the drying heat preservation time is 24h-48h; Preferably, the calcination temperature is 400°C-600°C; Preferably, the calcination holding time is 3h-10h.

7. An application of the rare earth denitration catalyst according to any one of claims 1 to 3, characterized in that: The rare earth denitration catalyst is used for the selective catalytic reduction of nitrogen oxides by ammonia.

8. The use according to claim 7, characterized in that: The operating temperature of the ammonia selective catalytic reduction of nitrogen oxides reaction is 200°C-550°C, preferably 250°C-500°C; Preferably, the rare earth denitration catalyst is subjected to activation pretreatment before being used in the selective catalytic reduction of nitrogen oxides by ammonia; Preferably, the holding temperature of the activation pretreatment is 300°C-500°C; Preferably, the ambient atmosphere of the activation pretreatment includes any one of ammonia, oxygen, sulfur dioxide, hydrogen, water vapor or argon, or a combination of at least two of them, preferably a mixture of ammonia, oxygen, sulfur dioxide and argon.

9. A denitration reactor, characterized in that: The denitration reactor comprises the rare earth denitration catalyst according to any one of claims 1-3.

10. A denitration device comprising the denitration reactor according to claim 9, characterized in that: The denitration device includes a mobile source gas denitration device and / or a fixed source gas denitration device.

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