An SCR catalyst for an H2 fuel engine

Abstract

This invention relates to the field of H2 fuel engine exhaust catalyst technology, specifically to an SCR catalyst for H2 fuel engines. The catalyst is divided into a first catalytic zone and a second catalytic zone. The function of the first catalytic zone is to remove NO from the catalyst inlet gas. x Under the action of H2, the H2-SCR reaction occurs, which converts NO into NO. x The nitrogen is reduced to N2, while generating the reaction intermediate NH3. The main function of the second catalytic zone is to store the NH3 generated at the front end (front electrode) of the catalyst at low temperature as a reducing agent, which reacts with the unreacted and leaked NO from upstream. x The NH3-SCR reaction occurs, which converts NO into NO. x It is reduced to N2. This invention utilizes the coordination of the first and second catalytic zones, allowing the catalyst to undergo H2-SCR and NH3-SCR reactions in the first and second catalytic zones respectively, jointly widening the active temperature window of the H2 fuel engine and purifying NO. x The effect is better and more complete.

Description

Technical Field

[0001] This invention belongs to the field of H2 fuel engine exhaust catalyst technology, specifically relating to an SCR catalyst for H2 fuel engines. Background Technology

[0002] The main components of fuel used in traditional internal combustion engine vehicles are hydrocarbons, and the combustion products include CO, CO2, and NO. x PM2.5, PM2.5, and other pollutants have become a major contributor to air pollution, negatively impacting human health and the environment. Traditional internal combustion engines, reliant on petroleum resources, must find alternative energy sources to alleviate the dual pressures of environmental protection and the energy crisis.

[0003] Compared to traditional vehicle fuels, using H2 as fuel does not produce greenhouse gases like CO2 or other harmful gases like HC and CO, as the combustion product of H2 is water. Only NO is emitted from the engine. x H2 is a pollutant, and it can be produced by electrolyzing water or from renewable energy sources such as solar and wind power. Therefore, H2 fuel engines are a future development direction.

[0004] Using H2 as a reducing agent, SCR technology is employed to treat NO in exhaust gas. x It can effectively reduce NO x The emissions. Currently, there is still much discussion regarding reducing NO emissions in H2 fuel engines. x There are almost no patents on SCR catalysts, only some for low-temperature NO reduction in diesel vehicles. x SCR catalysts, such as those reported in patent CN110072609A, can effectively purify NO using H2 as a reducing agent at low temperatures. x However, as the temperature increases, H2 is oxidized by excess O2, and NO... x Decreased conversion rate affects NO x Emissions reduction. In practical applications of H2 fuel engines, the highest exhaust temperature can reach 500℃. Therefore, in order to purify NO from H2 fuel engines... x Developing a SCR catalyst with a wide activity temperature window is a challenge that needs to be actively tackled. Summary of the Invention

[0005] The purpose of this invention is to address the issue of NO in H2 fuel engines. x To address the purification process and environmental impact, a wide-temperature-window SCR catalyst and its preparation method were developed. The catalyst is produced by coating a support with a noble metal coating and a molecular sieve coating, respectively, and adjusting their distribution on the support. This allows for effective purification of NO within a wide temperature window. xThis achieves the goal of exhaust gas purification for H2 fuel engines and overcomes the technical shortcomings of the current energy crisis.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] An SCR catalyst for an H2 fuel engine, the SCR catalyst comprising a first catalytic zone and a second catalytic zone, the first catalytic zone comprising a support material and a noble metal coating supported on the support material; the second catalytic zone comprising a support material and a molecular sieve coating supported on the support material; the first catalytic zone is disposed in the front section or pre-stage of the SCR catalyst, and the second catalytic zone is disposed in the rear section or post-stage of the SCR catalyst.

[0008] This invention proposes an SCR catalyst for an H2 fuel engine, which is divided into a first catalytic zone and a second catalytic zone. The first catalytic zone is located at the front end or pre-stage of the SCR catalyst, and the second catalytic zone is located at the rear end or post-stage of the SCR catalyst. The first catalytic zone is used to react with H2 at a low temperature to remove NO. x The nitrogen is reduced to N2, while generating the reaction intermediate NH3. The main function of the second catalytic zone is to store the NH3 generated at the front end (front electrode) of the catalyst at low temperature and use it as a reducing agent to treat NO leaked from upstream. x , will NO x It is reduced to N2, undergoing the NH3-SCR reaction. This invention utilizes the coordination of the first and second catalytic zones, enabling the catalyst to undergo both the H2-SCR and NH3-SCR reactions in the first and second catalytic zones respectively, collectively widening the activity temperature window of the H2 fuel engine and purifying NO. x The effect is better and more complete.

[0009] As a preferred embodiment of the present invention, the noble metal coating includes a platinum group metal and a first carrier, wherein the first carrier is a metal oxide material; the molecular sieve coating includes a molecular sieve material and an active component loaded on the molecular sieve material.

[0010] As a preferred embodiment of the present invention, the precious metal includes at least one of Pt, Pd, Rh, and Ru; more preferably, the platinum group metal is any one or a combination of two of Pt and Pd; the mass ratio of Pt to Pd is (10-1):(0-1).

[0011] Under the catalysis of the noble metal Pt, the reaction NO + 5 / 2H2 → NH3 + H2O occurs, generating the intermediate product NH3, which can be stored and utilized as a downstream or post-electrode catalyst. The addition of Pd enhances the thermal stability of the catalyst through the synergistic effect of the Pt-Pd interaction.

[0012] As a preferred embodiment of the present invention, the content of the precious metal is 0.5-5 g / ft. 3 .

[0013] More preferably, the content of the precious metal is 0.5-2 g / ft. 3 .

[0014] During the research and development process, the inventors discovered that the content of precious metals in the catalyst has a significant impact on the low-temperature activity and NH3 generation, with the precious metal content ranging from 1-2 g / ft. 3 The catalyst exhibits the best overall performance in terms of low-temperature activity and NH3 generation. Beyond this concentration, both low-temperature performance and NH3 generation show a decreasing trend. Therefore, considering both catalyst cost and overall catalytic performance, a precious metal content range of 1-2 g / ft is adopted. 3 .

[0015] As a preferred embodiment of the present invention, the metal oxide material includes any one or a combination of several of CeO2-Al2O3, MgO-CeO2-Al2O3, MgO-CeO2, SiO2-Al2O3, and Al2O3.

[0016] As a preferred embodiment of the present invention, the metal oxide material is any one or a combination of two of MgO-CeO2-Al2O3 and SiO2-Al2O3. In the MgO-CeO2-Al2O3 material, the molar ratio of the three substances is (3-5):1:(5-6); in the SiO2-Al2O3 material, the molar ratio of SiO2 and Al2O3 is 1:(1-2).

[0017] As a preferred embodiment of the present invention, the molecular sieve material is any one or a combination of several of Beta, ZSM-5, CHA, AEI, FAU, LTA, and AFX, and the active component is at least one of Cu, Fe, and Co. The specific content of the active component needs to be selected based on factors such as engine temperature window, oxygen content, and aging conditions.

[0018] As a preferred embodiment of the present invention, the molecular sieve is one or two of CHA and AEI, and the active component is any one or a combination of two of Cu or Fe.

[0019] The catalyst can be a single-stage segmented catalyst or a two-stage catalyst. The volume ratio of the coatings in the first catalytic zone and the second catalytic zone is 5:1 to 1:5.

[0020] The main temperature range for SCR reaction in the first catalytic zone is no higher than 300℃; the main temperature range for SCR reaction in the second catalytic zone is higher than 300℃.

[0021] The NH3 generated during the NH3-SCR reaction of the catalyst can also originate from hardware devices such as urea tanks and mixers added before the post-catalyst, using the NH3 from urea decomposition as a reducing agent to reduce NO. x Revert to N2 for better NO purification x .

[0022] A method for preparing an SCR catalyst for an H2 fuel engine includes the following steps:

[0023] S1: Prepare noble metal coating and molecular sieve coating respectively. Mill the noble metal coating and molecular sieve coating with silica sol to obtain noble metal slurry and molecular sieve slurry respectively.

[0024] S2: The precious metal slurry and molecular sieve slurry are coated onto the support in a segmented or graded manner to obtain an integral catalyst. After drying, the catalyst is calcined at a constant temperature of 450-550℃ for 2-5 hours under air atmosphere to obtain the H2-SCR catalyst.

[0025] As a preferred embodiment of the present invention, the preparation of the noble metal coating includes the following steps:

[0026] S1.1: According to the citric acid complexation method, with a molar ratio of citric acid to metal ions of 0.5:1 to 2:1, citric acid is added to the dissolved salt solution. The salt solution is then placed in a water bath and stirred at 80 to 100°C until it reaches a gel state. It is then dried at 50 to 100°C and calcined in air at 450 to 550°C for 2 to 5 hours to obtain the first carrier material. Then, the weighed noble metal solution is loaded onto the carrier material prepared above by the equal volume impregnation method. After drying and calcination, a noble metal coating is obtained.

[0027] As a preferred embodiment of the present invention, the preparation of the molecular sieve coating includes the following steps:

[0028] S1.2: The active component precursor is transferred to the molecular sieve by ion exchange, filtered, washed, dried at 80-120℃, and then calcined in air at 450-550℃ for 2-5 hours to obtain the molecular sieve coating.

[0029] As a preferred technical solution of the present invention, the precursor of the metal oxide in the first carrier material is a nitrate solution of metal ions, including Al(NO3)3, Mg(NO3)2, and Ce(NO3)3, during the preparation process.

[0030] Salt solutions of precious metal materials include any one of the following: platinum nitrate, chloroplatinic acid, tetraammineplatinum bicarbonate, palladium nitrate, and tetraamminepalladium bicarbonate.

[0031] In the above-mentioned exhaust gas treatment catalyst, the carrier material for the coating is preferably cordierite, the noble metal is preferably Pt and Pd, the noble metal carrier material is preferably MgO-CeO2-Al2O3, the molecular sieve is preferably CHA, and the active component of the molecular sieve is preferably Cu.

[0032] The noble metal Pt facilitates the activation of reactants, while Pd improves the utilization rate of the reducing agent H2 and exhibits good stability. The noble metal support material MgO-CeO2-Al2O3 enhances the dispersibility of the noble metal and generates a large amount of NH3 at low temperatures, which can be stored and reused in the later stages. The molecular sieve CHA provides acidic sites, allowing for the storage of NH3 generated in the earlier stages at low temperatures with good stability. The active component Cu in the molecular sieve has a higher exchange rate on the sieve, which is beneficial for NO. x The purification is relatively good.

[0033] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0034] 1. In the catalyst of the present invention, the catalyst is divided into two regions, a first catalytic region and a second catalytic region, which have different functions. The first catalytic region is used to react with H2 at low temperature to react NO. x The catalyst is reduced to N2, simultaneously generating the reaction intermediate NH3. The main function of the second catalytic zone is to store the NH3 generated at the front stage (front electrode) of the catalyst at low temperatures. The NH3 stored at low temperatures can then be used as a reducing agent to treat NO at medium and high temperatures. x , will NO x It is reduced to N2, undergoing the NH3-SCR reaction. This invention utilizes the coordination of the first and second catalytic zones, enabling the catalyst to undergo both the H2-SCR and NH3-SCR reactions in the first and second catalytic zones respectively, collectively widening the activity temperature window of the H2 fuel engine and purifying NO. x The effect is better and more complete.

[0035] 2. The technical solution of this invention achieves a wide temperature window, enabling the catalyst to achieve optimal NO production at both low (< 300℃) and medium-high (≥ 300℃) temperatures. x Purification. Detailed Implementation

[0036] The present invention will now be described in detail.

[0037] To make the objectives, technical solutions, and advantages of this invention clearer, the following embodiments provide a more detailed description of the invention. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of the invention.

[0038] Example 1

[0039] This embodiment provides a method for preparing an SCR catalyst for an H2 fuel engine, specifically including the following steps:

[0040] S1: Prepare noble metal coating and molecular sieve coating respectively. Mill the noble metal coating and molecular sieve coating with silica sol to obtain noble metal slurry and molecular sieve slurry respectively.

[0041] S2: The precious metal slurry and molecular sieve slurry are coated onto the support in a segmented or graded manner to obtain an integral catalyst. After drying, the catalyst is calcined at a constant temperature of 450-550℃ for 2-5 hours under air atmosphere to obtain the H2-SCR catalyst.

[0042] In S1, the preparation of the noble metal coating includes the following steps:

[0043] S1.1: According to the citric acid complexation method, with a molar ratio of citric acid to metal ions of 0.5:1 to 2:1, citric acid is added to the dissolved salt solution. The salt solution is then placed in a water bath and stirred at 80 to 100°C until it reaches a gel state. It is then dried at 50 to 100°C and calcined in air at 450 to 550°C for 2 to 5 hours to obtain the carrier material. Then, the weighed noble metal solution is loaded onto the carrier material prepared above by the equal volume impregnation method. After drying and calcination, a noble metal coating is obtained.

[0044] In S1, the preparation of the molecular sieve coating includes the following steps:

[0045] S1.2: The active component precursor is transferred to the molecular sieve by ion exchange, filtered, washed, dried at 80-120℃, and then calcined in air at 450-550℃ for 2-5 hours to obtain the molecular sieve coating.

[0046] In the following examples, unless otherwise specified, the SCR catalyst was prepared using the preparation method described above.

[0047] Example 2

[0048] Example 2 provides an SCR catalyst for an H2 fuel engine; in this example, the influence of the content of precious metals on the catalytic performance of the catalyst is mainly studied.

[0049] Al(NO3)3 and Ce(NO3)3 solutions were dissolved separately in deionized water (Ce:Al molar ratio = 1:1) and thoroughly mixed to prepare a salt solution. C6H8O7·H2O was added to the prepared salt solution at a molar ratio of citric acid to all metal ions of 1:1. The mixture was then placed in a water bath and stirred at 80°C until it reached a gel state. After drying at 100°C, it was calcined at 500°C for 2 hours to obtain the Ce-Al support material.

[0050] Then, platinum nitrate solution was loaded onto the Ce-Al material prepared above using an equal-volume impregnation method. After drying at 80°C, the material was calcined at 500°C for 2 hours to obtain a noble metal coating. The noble metal coating was then ball-milled with silica sol to obtain a noble metal coating slurry with a solid content of 45%.

[0051] The molecular sieve material was H-CHA, and the active component was copper. A 0.1 mol / L copper nitrate solution was loaded onto the H-CHA material via ion exchange. The resulting slurry was filtered, washed, dried at 80°C, and then calcined at 500°C for 2 hours to obtain a molecular sieve coating. The molecular sieve coating was then ball-milled with silica sol to obtain a molecular sieve coating slurry with a solid content of 50%.

[0052] Based on the above method, a series of catalysts with different platinum contents were prepared;

[0053] Specifically, in the catalyst, a precious metal coating slurry is applied to one end (as the front section) of a ceramic support with dimensions of 1in*3in and a pore density of 400 mesh, with the coating length covering 2 / 3 of the entire support and a loading of 80 g / L; (the precious metal content is set at 1 g / ft). 3 2g / ft 3 3g / ft 3 5g / ft 3 After drying at 80℃, the prepared molecular sieve coating was applied to the other end of the support (as the rear section), with a coating length accounting for 1 / 3 of the entire support and a loading of 80 g / L. After drying at 80℃, it was calcined at a constant temperature of 450℃ in a muffle furnace for 2 hours to obtain the SCR catalyst.

[0054] As shown in Table 1:

[0055] Table 1 shows the parameter information of SCR catalysts with different precious metal contents.

[0056]

[0057]

[0058] The above four SCR catalysts were subjected to NO treatment in a fixed-bed reactor. xConversion efficiency test. The simulated gas composition during the test was: [H2] = 0.5%, [NO2] = 0.5%. x [O2] = 500 ppm, [H2O] = 10%, [N2] = 7%, N2 as the balance gas, space velocity 60000 h⁻¹ -1 The reaction temperatures were 150℃, 175℃, 200℃, 300℃, 400℃, and 500℃. The conversion efficiency results are shown in Table 2.

[0059] Table 2 shows the NO content of the catalysts under different precious metal contents. x Conversion efficiency

[0060]

[0061] Analysis of the above experimental results shows that different precious metal contents affect NO. x Conversion efficiency has a certain impact, with a precious metal content of 2g / ft. 3 At that time, the test temperature range NO x It has the best conversion efficiency.

[0062] Example 3

[0063] This embodiment further investigates the effect of the synergistic cooperation between the first support material and the platinum group metals on the NOx conversion efficiency (%) in the noble metal coating, based on Example 2; specifically, the parameter information of the SCR catalyst is summarized in Table 3;

[0064] Table 3 shows the parameter information of SCR catalysts composed of different noble metal support materials.

[0065]

[0066] The conversion efficiency results are shown in Table 4:

[0067] Table 4 shows the NO content of catalysts with different noble metal support materials. x Conversion efficiency

[0068]

[0069] Analysis of the above experimental results shows that different noble metal carrier materials have varying effects on NO. x Conversion efficiency has a certain impact, among which MgO-CeO2-Al2O3 material has the best activity, and the test temperature range NO x The conversion efficiency is all above 50%.

[0070] Example 4

[0071] This embodiment further examines the volume ratio of the noble metal coating to the molecular sieve coating for NO, based on Embodiment 3. xThe effect of conversion efficiency; a series of catalysts were prepared based on different volume ratios of the two.

[0072] Specifically, in the catalyst, a noble metal coating slurry is applied to one end of a ceramic support with dimensions of 1in*4in and a pore density of 400 mesh (as the front section); the loading is 80 g / L. After drying at 80℃, the prepared molecular sieve coating is applied to the other end of the support (as the rear section), with a loading of 80 g / L (the volume ratio of the noble metal coating to the molecular sieve coating is set to 4:1, 3:1, 1:1, and 1:3, respectively). After drying at 80℃, it is calcined at a constant temperature of 450℃ for 2 hours in a muffle furnace to obtain the SCR catalyst.

[0073] Table 5 shows the parameter information of SCR catalysts with different volume ratios of noble metal coatings and molecular sieve coatings.

[0074]

[0075] The conversion efficiency results are shown in Table 6:

[0076] Table 6 shows the NO content of the catalysts under different volume ratios of noble metal coating and molecular sieve coating. x Conversion efficiency

[0077]

[0078] Analysis of the above experimental results shows that different volume ratios of noble metal coatings to molecular sieve coatings have a significant impact on NO. x Conversion efficiency has a certain impact, among which the catalyst prepared at a volume ratio of 1:1 exhibits excellent NO conversion efficiency. x Purification effect.

[0079] Example 5

[0080] This embodiment, based on Example 4, breaks down catalyst S4-3 into a two-stage catalyst and introduces NH3 externally to further enhance the high-temperature NO production. x Purification efficiency. Details are as follows:

[0081] The SCR catalyst prepared in Examples S4-3 was cut into two catalysts (the front catalyst was coated with a noble metal, and the back catalyst was coated with a molecular sieve) and subjected to NO reaction in two fixed-bed reactors. x Conversion efficiency test: catalyst overall space velocity was 60,000 h⁻¹ -1 The pre-catalyst was placed in the first fixed-bed reactor, and the simulated gas composition was: [H2] = 0.5%, [NO2] = 0.5%. x [O2] = 500 ppm, [H2O] = 10%, [N2] = 7%, N2 is used as the balance gas, and the space velocity is 120,000 h⁻¹. -1The catalyst was then placed in a second fixed-bed reactor, and the simulated gas tested contained 500 ppm NO. x In addition to 10% O2, 7% H2O and N2, NH3 was supplemented into the test gas according to the concentration of NH3 produced by the pre-catalyst to ensure that the ammonia-nitrogen ratio was 1.0 at each temperature point. The reaction temperatures were 150℃, 175℃, 200℃, 300℃, 400℃ and 500℃, and the space velocity was 120000h. -1 .

[0082] The conversion efficiency results are shown in Table 7:

[0083] Table 7 shows the NO content under external supplementation of NH3. x Conversion efficiency

[0084]

[0085] Analysis of the above experimental results shows that: S5 NO x The average conversion rate remained above 75% between 150-200℃ and above 90% between 300-500℃, indicating that external supplementation of NH3 can further enhance NO conversion in the medium- and high-temperature range. x Conversion efficiency.

[0086] Based on the above tests, the optimal parameters for SCR catalysts are as follows:

[0087] Table 8:

[0088]

[0089] Comparative Example 1

[0090] The Pt content in the noble metal coating was set to 6 g / ft. 3 Other sample preparation methods are the same as in Example 2, and the SCR catalyst is obtained and designated as B1.

[0091] Comparative Example 2

[0092] The noble metal support material was set as H-CHA, and the other sample preparation methods were the same as in Example 3, resulting in an SCR catalyst, which was denoted as B2.

[0093] Comparative Example 3

[0094] In this comparative example, the main study focuses on the effect of changing the order of the noble metal coating and the molecular sieve coating on NO. x The purification effect is the same as in Examples 4-3, and the preparation methods for other samples are the same.

[0095] The catalyst uses MgO-CeO2-Al2O3 as the primary support material and Pt as the noble metal at a concentration of 2 g / ft.3 The molecular sieve material used is H-CHA, and the active component is copper.

[0096] Specifically, in the catalyst, a molecular sieve coating slurry is coated onto one end of a support with dimensions of "1in*4in" and a pore density of 400 mesh (as the front section), with a loading of 120 g / L and a coating length accounting for 1 / 2 of the entire support. After drying at 80°C, a noble metal coating slurry is then coated onto the other end of the support (as the rear section), with a coating length accounting for 1 / 2 of the entire support. After drying at 80°C, it is calcined at a constant temperature of 500°C for 2 hours in a muffle furnace to obtain the SCR catalyst, which is designated as B3.

[0097] The conversion efficiency results are shown in Table 9:

[0098] Table 9 shows the comparative catalyst NO. x Conversion efficiency

[0099]

[0100] Analysis of the above experimental results shows that the precious metal content in Comparative Example 1 is 6 g / ft. 3 At that time, due to its excessive oxidizing power, the low-temperature reducing agent H2 was oxidized by oxygen, and NO... x The conversion rate decreased, and the activity at medium and high temperatures also decreased significantly with increasing temperature. The catalyst prepared in Comparative Example 2 using H-CHA as the first support material exhibited very low activity throughout the entire test temperature range. In Comparative Example 3, after the noble metal coating and molecular sieve coating were swapped (molecular sieve coating in the first stage, noble metal coating in the second stage), only the effect of the noble metal coating was achieved, with almost no activity in the medium and high temperature range.

[0101] The above comparative analysis clearly shows that in the technical solution of the present invention, the catalyst is coated according to two different functional sections: a first catalytic zone and a second catalytic zone. The first catalytic zone uses a MgO-CeO2-Al2O3 mixed metal oxide material as the first support, with a noble metal concentration of 2-3 g / ft. 3 The Pt catalytic component reacts with H2 in a temperature range of 100-300℃ to produce NO. x The nitrogen is reduced to N2, simultaneously generating the reaction intermediate NH3. The second catalytic zone uses a coating material with H-CHA molecular sieve material and copper as the active component to store the generated NH3. Within a temperature range of 300-500℃, NH3 is used as a reducing agent to treat NO. x , will NO x It is reduced to N2, undergoing the NH3-SCR reaction. The synergistic effect between the low-temperature and medium-high-temperature zones (first and second catalytic zones) widens the active temperature window of the H2 fuel engine, allowing NO to... xThe purification effect is more thorough, achieving the exhaust purification target of H2 fuel engines and overcoming the technical shortcomings of the current energy crisis. This is of great significance for the practical application of H2 fuel engines and the reduction of vehicle exhaust emissions.

[0102] The above description is merely a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the concept described herein through the above teachings or related technologies or knowledge. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. An SCR catalyst for H2 fuel engines, characterized by, The SCR catalyst includes a first catalytic region and a second catalytic region. The first catalytic region includes a support material and a noble metal coating supported on the support material. The second catalytic region includes a support material and a molecular sieve coating supported on the support material. The first catalytic region is disposed in the front section or pre-stage of the SCR catalyst, and the second catalytic region is disposed in the rear section or post-stage of the SCR catalyst. The first catalytic zone is used to react with H2 at low temperature to reduce NOx to N2 and generate NH3; the second catalytic zone is used to store the NH3 generated in the first catalytic zone and to use the stored NH3 as a reducing agent to carry out the NH3-SCR reaction to reduce NOx to N2 at medium and high temperatures. The noble metal coating includes platinum group metals and a first carrier, wherein the first carrier is a metal oxide material; the molecular sieve coating includes a molecular sieve material and an active component loaded on the molecular sieve material; The platinum group metal is any one or a combination of two of Pt and Pd; the mass ratio of Pt to Pd is (10~1):(0~1); and the content of the noble metal in the noble metal coating is 0.5-5 g / ft. 3 ; The metal oxide material includes any one or a combination of several of CeO2-Al2O3, MgO-CeO2-Al2O3, MgO-CeO2, SiO2-Al2O3, and Al2O3; The molecular sieve material is any one or a combination of several of Beta, ZSM-5, CHA, AEI, FAU, LTA, and AFX; The active component contains at least one of Cu, Fe, and Co; The volume ratio of the noble metal coating to the molecular sieve coating is 5:1 to 1:

5.

2. The SCR catalyst for H2 fuel engine according to claim 1, characterized by, In the catalyst, NH3-SCR reaction is achieved by adding urea tank before the post-catalyst to provide NH3.

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