CN108435238A - A Mn-La-Ce catalyst for selective catalytic reduction of NO and its application - Google Patents

Abstract

The invention discloses a Mn-La-Ce catalyst for selective catalytic reduction of NO and an application thereof, specifically belonging to the fields of exhaust gas treatment technology and environmental protection catalytic environment. The catalyst is prepared by co-impregnation method with ZSM-5 as the carrier, Mn as the main active component and transition metals La and Ce as additives. Firstly weigh the Mn(NO ₃ ) ₂ 4H ₂ O, La(NO ₃ ) ₄ 6H ₂ O and Ce(NO ₃ ) ₄ 6H ₂ O solutions and impregnate them with ZSM‑5 molecular sieves, then stir in a water bath until The water evaporates completely. Then the prepared powder was dried overnight in a drying oven, calcined at 500-550° C. for 5 hours, and cooled naturally to prepare the Mn-La-Ce/ZSM-5 molecular sieve catalyst for selective catalytic reduction of NO. The Mn-La-Ce/ZSM-5 molecular sieve catalyst of the present invention has a high ability of selective catalytic reduction of NO, and can effectively remove NO and hydrocarbons. At the same time, the additives La, Ce and the active component Mn can play a good synergistic catalytic effect, improve the low-temperature activity of the catalyst, reduce the light-off temperature of the catalyst, and widen the temperature operating window of the catalyst.

Description

A Mn-La-Ce catalyst for selective catalytic reduction of NO and its application

technical field

The invention relates to a Mn-La-Ce catalyst for selective catalytic reduction of NO and its application, specifically belonging to the fields of exhaust gas treatment technology and environmental protection catalytic environment.

Background technique

Nitrogen oxide (NOx) is one of the main pollutants in the atmosphere. It can not only cause acid rain, photochemical smog, ozone layer destruction and smog, but also seriously affect human health and endanger the living environment of humans, animals and plants. NOx mainly includes NO, NO ₂ and N ₂ O, among which, NO occupies more than 90%. It mainly comes from stationary sources such as industrial boilers, thermal power plants, and coal-fired power plants, and mobile sources such as motor vehicle exhaust. The latest data show that NOx emissions are increasing year by year with the increase of mobile sources. Therefore, with the increasingly prominent environmental problems in our country, the government has also formulated increasingly stringent NOx emission standards. How to effectively remove nitrogen oxides Emissions have become a mainstream research topic now.

NOx removal technologies include: wet removal technology, storage reduction technology (NSR), direct catalytic decomposition technology, plasma removal technology, selective non-catalytic reduction technology (SNCR), and selective catalytic reduction technology (SCR) . At present, among numerous denitrification technologies, SCR technology is one of the most potential NOx purification technologies. Under the action of a catalyst, NOx is selectively reduced to _N2 by adding a reducing agent to the reaction system or reducing substances in the exhaust gas. , so that the NOx in the exhaust gas can be degraded.

The core of selective reduction technology (SCR) lies in the catalyst, and SCR catalysts include commercial V ₂ O ₅ -WO ₃ /TiO ₂ catalysts, noble metal catalysts, metal oxide catalysts and molecular sieve catalysts. Among them, the commercialized V ₂ O ₅ -WO ₃ /TiO ₂ catalysts at home and abroad have poor low-temperature activity, narrow operating temperature window (350-400°C), and V ₂ O ₅ is a highly toxic substance, which is harmful to human health and the environment larger. Although the noble metal catalyst has excellent catalytic performance, its preparation cost is too high, and it is easy to form sulfate with the sulfide in the exhaust gas, which leads to catalyst deactivation due to sulfur poisoning. Metal oxide catalysts have low catalytic activity when the space velocity is high, are prone to _SO poisoning, and after high-temperature aging, the structure collapses and the specific surface area decreases, which leads to catalyst deactivation and cannot meet increasingly stringent emission standards. Therefore, the research on molecular sieve catalysts with high catalytic activity, wide operating temperature window and low cost has become the focus, and the development of highly active molecular sieve catalysts with independent intellectual property rights is also extremely meaningful.

The design idea of this patent is to firstly screen out metal active components with good NO removal effect and low cost. The interaction between catalysts can improve the low-temperature denitrification activity of the catalyst, widen the operating temperature window of the catalyst, and improve the stability of the catalyst. Therefore, we have done a lot of exploration work according to the classification and structural characteristics of metals. We explored active components such as Mn, Ce, Ni, Fe, Zn, etc., and found that Mn has certain low-temperature activity, but its stability is poor. Next, we explored the addition of La and Ce additives to improve the low-temperature activity and stability of the catalyst. The study found that the metal composite oxide structure formed by La, Ce additives and active components has the ability to store and release oxygen. The interaction between the catalyst, the additive and the active component promotes the SCR reaction and greatly improves the low-temperature activity of the catalyst.

Contents of the invention

The purpose of the present invention is to provide a Mn-La-Ce catalyst for selective catalytic reduction _of NO and its application. The catalyst has good catalytic activity for the selective reduction of NO by _C3H6 present in the tail gas, and The pollutant C ₃ H ₆ is removed at the same time. The first problem solved by the invention is to develop a highly active molecular sieve catalyst with independent intellectual property rights; the second problem solved by the invention is to improve the low-temperature activity of the catalyst and widen the operating temperature window of the catalyst, and to achieve high efficiency at 150-390°C NO removal, the highest NO conversion rate can reach 95-96%. The third problem solved by the invention is to adopt the co-impregnation method, the preparation process is simple and easy to control, and the industrial production is easy to realize and the cost is low.

The invention discloses a Mn-La-Ce catalyst for selective catalytic reduction of NO and application thereof, wherein the carrier of the catalyst is a molecular sieve with MFI skeleton type.

Further, it is preferred that the catalyst carrier of the present invention is ZSM-5, that is, a Mn-La-Ce catalyst for selective catalytic reduction of NO in the present invention and its application, and the catalyst is supported by ZSM-5 molecular sieve.

The catalyst of the present invention uses metal oxides as active components, and the metal oxides are at least one of Ni, Fe, Ce, Mn and Zn.

Further, it is preferable that the active component of the catalyst of the present invention is Mn, that is, a Mn-La-Ce catalyst for selective catalytic reduction of NO in the present invention and its application, and the catalyst uses the metal oxide of Mn as the active group point.

Further, in order to achieve a better NO degradation effect, the mass percentage of the active component Mn is preferably 5% to 25% with the mass of the carrier as 100%.

Further, in order to achieve a better NO degradation effect, it is preferable that the mass percentage of the active component Mn is 15%-20%.

Further, in order to achieve a better NO degradation effect, it is more preferable that the mass percentage of the active component Mn is 20%.

The active component of the catalyst described in the present invention is Mn, and the catalyst also contains a promoter, that is, a Mn-La-Ce catalyst and application thereof for selective catalytic reduction of NO in the present invention, and the catalyst promoter is La, Ce, Fe, Zr or Ni.

Further, in order to achieve a better effect of degrading NO, it is preferred that the auxiliary agent is La, Ce or Ni.

Further, in order to achieve a better NO degradation effect, it is preferred that the additive is La.

Further, in order to achieve a better effect of degrading NO, the mass percentage of the additive La is preferably 0.5% to 10% with the mass of the carrier as 100%.

Further, in order to achieve a better effect of degrading NO, it is preferable that the mass percentage of the additive La is 3%-7%.

Further, in order to achieve a better effect of degrading NO, it is preferable that the mass percentage of the additive La is 7%.

The active component of the catalyst described in the present invention is Mn, and the catalyst also contains a second promoter, that is, a Mn-La-Ce catalyst for selective catalytic reduction of NO and its application, and the second promoter of the catalyst is The agent is Ce or Zr.

Further, in order to achieve a better NO degradation effect, it is preferred that the second additive is Ce.

Further, in order to achieve a better effect of degrading NO, the weight of the carrier is 100%, preferably the mass percentage of the second additive Ce is 0.5%-7%.

Further, in order to achieve a better NO degradation effect, preferably, the mass percentage of the second additive Ce is 1%-5%.

Further, in order to achieve a better effect of degrading NO, it is preferable that the mass percentage of the second additive Ce is 5%.

The catalyst of the present invention uses ZSM-5 molecular sieve as a carrier, metal element MN as an active component, and transition metals La and Ce as auxiliary agents to obtain a Mn-La-Ce/ZSM-5 molecular sieve catalyst, and use it for SCR degradation NO.

The Mn-La-Ce/ZSM-5 molecular sieve catalyst prepared by the present invention has a NO conversion rate of 96% at 200°C under the condition that the feed gas components are 400ppm C ₃ H ₆ , 400ppm NO and 4% O ₂ . The NO conversion rate at ℃ is 95%, and the NO conversion rate at 300 °C is 85%. The optimal NO conversion rate of the catalyst of the present invention is 96%, the light-off temperature is 150°C, and the operating temperature window T ₅₀ is 150-390°C. Compared with the catalytic activity of the 10%Mn/ZSM-5 catalyst (the optimal NO conversion is about 63% at 350°C), the light-off temperature (225°C) and the operating temperature window T ₅₀ (225-380°C), this The Mn-La-Ce/ZSM-5 molecular sieve catalyst used for SCR degradation of NO provided by the invention has high medium and low temperature catalytic activity, low light-off temperature and wide operating temperature window.

A kind of preparation method of the Mn-La-Ce catalyst of selective catalytic reduction NO of the present invention:

It can be a conventional catalyst preparation method, such as a co-impregnation method, in which the carrier is added to a metal salt solution for co-impregnation, then evaporated to dryness in a water bath, dried overnight, and roasted to obtain the catalyst.

Mn-La-Ce/ZSM-5 molecular sieve catalyst preparation method of the present invention, its specific steps are as follows:

(1) prepare ZSM-5 molecular sieve carrier;

(2) The weighed Mn(NO ₃ ) ₂ ·4H ₂ O, La(NO ₃ ) ₄ ·6H ₂ O, Ce(NO ₃ ) ₄ ·6H ₂ O solutions were impregnated in ZSM-5 together, and After 40 minutes, evaporate to dryness in a water bath at 75-85°C;

(3) Then place it in an oven and dry it at 100-120°C for 12 hours;

(4) putting the obtained product of step (3) into a muffle furnace and roasting at a high temperature of 500-550° C. for 5 hours;

(5) naturally cooling the obtained product in step (4) to room temperature to obtain the Mn-La-Ce/ZSM-5 molecular sieve catalyst for selective catalytic reduction of NO.

(6) Crushing the catalyst tablet obtained in step (5) to 20-40 meshes.

Preferably, the doping amount of Ce in step (2) is 1%-5%.

Preferably, the doping amount of La in step (3) is 3%-7%.

Preferably, the doping amount of Mn in step (4) is 15%-20%.

The present invention has the following advantages:

1. Mn-La-Ce/ZSM-5 molecular sieve catalyst has better catalytic activity and wider temperature operating window. At 200°C, the NO conversion rate reaches 95-96%, the light-off temperature is 150°C, and the operating temperature window T ₅₀ (T ₅₀ is when the NO conversion rate reaches over 50%) is 150-390°C.

2. Prepare Mn-La-Ce/ZSM-5 molecular sieve catalyst by co-impregnation method. This preparation method has simple process, low cost and high catalytic activity for SCR reaction. At the same time, it can purify C ₃ H ₆ in motor vehicle exhaust , the preparation conditions are easy to control and suitable for industrial production.

Description of drawings

Fig. 1 is the catalytic activity test figure of the catalyst prepared in embodiment 1 and comparative example 1, example 2, example 3, example 4.

Fig. 2 is the catalytic activity test diagram of the catalyst prepared in Example 1, Example 2, Example 3, Example 4, Example 5 and Example 6.

Fig. 3 is the catalytic activity test chart of the catalyst prepared in Example 11, Example 17 and Comparative Example 5, Example 6, Example 7.

Fig. 4 is the catalytic activity test chart of the catalyst prepared in Example 1, Example 7, Example 8, Example 9, Example 10, Example 11 and Example 12.

Fig. 5 is the catalytic activity test diagram of the catalyst prepared in Example 1, Example 13, Example 14, Example 15, Example 16, Example 17 and Example 18.

Fig. 6 is the catalytic activity test diagram of the catalyst prepared in Example 1, Example 17, Example 19, Example 20, Example 21, Example 22 and Example 23.

Fig. 7 is the XRD spectrogram of the catalyst prepared in Example 1, Example 17 and Example 22.

Detailed ways

The technical problem solved by the invention is to provide a catalyst that can widen the operating temperature window, improve catalytic activity, reduce production cost and have a simple preparation process in the process of degrading NO.

The invention discloses a Mn-La-Ce catalyst for selective catalytic reduction of NO and application thereof, wherein the carrier of the catalyst is a molecular sieve with MFI skeleton type.

Further, it is preferred that the catalyst carrier of the present invention is ZSM-5, that is, a Mn-La-Ce catalyst for selective catalytic reduction of NO in the present invention and its application, and the catalyst is supported by ZSM-5 molecular sieve.

The catalyst of the present invention uses metal oxides as active components, and the metal oxides are at least one of Ni, Fe, Ce, Mn and Zn.

Further, it is preferable that the active component of the catalyst of the present invention is Mn, that is, a Mn-La-Ce catalyst for selective catalytic reduction of NO in the present invention and its application, and the catalyst uses the metal oxide of Mn as the active group point.

Further, in order to achieve a better NO degradation effect, the mass percentage of the active component Mn is preferably 5% to 25% with the mass of the carrier as 100%.

Further, in order to achieve a better NO degradation effect, it is preferable that the mass percentage of the active component Mn is 15%-20%.

Further, in order to achieve a better NO degradation effect, it is more preferable that the mass percentage of the active component Mn is 20%.

The active component of the catalyst described in the present invention is Mn, and the catalyst also contains a promoter, that is, a Mn-La-Ce catalyst and application thereof for selective catalytic reduction of NO in the present invention, and the catalyst promoter is La, Ce, Fe, Zr or Ni.

Further, in order to achieve a better effect of degrading NO, it is preferred that the auxiliary agent is La, Ce or Ni.

Further, in order to achieve a better NO degradation effect, it is preferred that the additive is La.

Further, in order to achieve a better effect of degrading NO, the mass percentage of the additive La is preferably 0.5% to 10% with the mass of the carrier as 100%.

Further, in order to achieve a better effect of degrading NO, it is preferable that the mass percentage of the additive La is 3%-7%.

Further, in order to achieve a better effect of degrading NO, it is preferable that the mass percentage of the additive La is 7%.

The active component of the catalyst described in the present invention is Mn, and the catalyst also contains a second auxiliary agent, that is, a Mn-La-Ce catalyst for selective catalytic reduction of NO in the present invention and its application, and the catalyst second The auxiliary agent is Ce or Zr.

Further, in order to achieve a better NO degradation effect, it is preferred that the second additive is Ce.

Further, in order to achieve a better effect of degrading NO, the weight of the carrier is 100%, preferably the mass percentage of the second additive Ce is 0.5%-7%.

Further, in order to achieve a better NO degradation effect, preferably, the mass percentage of the second additive Ce is 1%-5%.

Further, in order to achieve a better effect of degrading NO, it is preferable that the mass percentage of the second additive Ce is 5%.

The catalyst of the present invention uses ZSM-5 molecular sieve as a carrier, the metal element Mn as an active component, and transition metals La and Ce as auxiliary agents to obtain a Mn-La-Ce/ZSM-5 molecular sieve catalyst, and use it for SCR degradation NO.

The Mn-La-Ce/ZSM-5 molecular sieve catalyst prepared by the present invention has a NO conversion rate of 96% at 200°C under the condition that the feed gas components are 400ppm C ₃ H ₆ , 400ppm NO and 4% O ₂ . The NO conversion rate at ℃ is 95%, and the NO conversion rate at 300 °C is 85%. The optimal NO conversion rate of the catalyst of the present invention is 96%, the light-off temperature is 150°C, and the operating temperature window T ₅₀ is 150-390°C. Compared with the catalytic activity of the 10%Mn/ZSM-5 catalyst (the optimal NO conversion is about 63% at 350°C), the light-off temperature (225°C) and the operating temperature window T ₅₀ (225-380°C), this The Mn-La-Ce/ZSM-5 molecular sieve catalyst used for SCR degradation of NO provided by the invention has high medium and low temperature catalytic activity, low light-off temperature and wide operating temperature window.

A kind of preparation method of the Mn-La-Ce catalyst of selective catalytic reduction NO of the present invention:

It can be a conventional catalyst preparation method, such as a co-impregnation method, in which the carrier is added to a metal salt solution for co-impregnation, then evaporated to dryness in a water bath, dried overnight, and roasted to obtain the catalyst.

Mn-La-Ce/ZSM-5 molecular sieve catalyst preparation method of the present invention, its specific steps are as follows:

(1) Prepare ZSM-5 molecular sieve carrier

(2) The weighed Mn(NO ₃ ) ₂ ·4H ₂ O, La(NO ₃ ) ₄ ·6H ₂ O, Ce(NO ₃ ) ₄ ·6H ₂ O solutions were impregnated in ZSM-5 together, and After 40 minutes, evaporate to dryness in a water bath at 75-85°C;

(3) Then place it in an oven and dry it at 100-120°C for 12 hours;

(4) putting the obtained product of step (3) into a muffle furnace and roasting at a high temperature of 500-550° C. for 5 hours;

(5) naturally cooling the obtained product in step (4) to room temperature to obtain the Mn-La-Ce/ZSM-5 molecular sieve catalyst for selective catalytic reduction of NO.

(6) Crushing the catalyst tablet obtained in step (5) to 20-40 meshes.

Preferably, the doping amount of Ce in step (2) is 1%-5%.

Preferably, the doping amount of La in step (3) is 3%-7%.

Preferably, the doping amount of Mn in step (4) is 15%-20%.

The specific embodiments of the present invention will be further described below in conjunction with the examples, and the present invention is not limited to the scope of the examples.

The synthesis of embodiment 1 20%Mn/ZSM-5 catalyst

Weigh 1.8276g of Mn(NO ₃ ) ₂ ·4H ₂ O and 30ml of deionized water, mix and stir until dissolved; add 2g of ZSM-5 molecular sieve and impregnate for 40min; then stir in a water bath at 75-85°C until the water evaporates completely; then The prepared powder is dried in a drying oven at 100-120°C for 12 hours, and calcined at 500-550°C for 5 hours; the calcined powder is crushed to 20-40 mesh with a tablet machine under a pressure of 10Mpa to obtain 10% Mn/ZSM-5 catalyst was used.

Catalyst evaluation

The activity evaluation of the catalyst was carried out in a self-made continuous flow fixed-bed reactor. The reaction tube is a quartz tube with an inner diameter of 6 mm and a length of 33 cm. The reaction temperature is measured by a thermocouple placed in the middle of the reaction tube, and the reaction temperature is controlled by a temperature programming controller. The gas flow rate is controlled by a mass flow meter. The reaction raw material gas: 400ppm C ₃ H ₆ , 400ppm NO, 4% O ₂ and balance gas Ar. In the experiment, the amount of catalyst is 0.2g, the reaction temperature is 150℃～500℃, every 50℃ sampling. The flue gas analyzer (MRU, VARIO PLUS) was used for detection to calculate the conversion rate of NO and C ₃ H ₆ . The conversion curves of catalysts to NO and C ₃ H ₆ at different temperature points are shown in Figures 1, 2, 4, 5, and 6. At 350°C, the conversion rate of NO is 63%, the light-off temperature is 225°C, and the operating temperature The window T ₅₀ is 225-380°C, see Table 1.

Example 2-6

Compared with Example 1, only the Mn content of the catalyst active component is different, and the other processes are the same as Example 1 to prepare Mn/ZSM-5 catalysts with different Mn content.

Catalyst evaluation

According to the evaluation method of Example 1, the conversion curves of the catalyst to NO and C ₃ H ₆ at different temperature points are shown in Fig. 2 . The conversion rate and operating window temperature of the optimum activation temperature are shown in Table 1.

Example 7-12

The difference from Example 1 is that the auxiliary agent Ce is added, and the content of the auxiliary agent Ce is different. The other processes are the same as in Example 1, specifically as follows: Weigh 1.8276g of Mn(NO ₃ ) ₂ ·4H ₂ O and 0.436g La(NO ₃ ) ₄ ·6H ₂ O, mixed and stirred until dissolved; added 2g ZSM-5 molecular sieve and impregnated for 40min; then stirred in a water bath at 75-85°C until the water evaporated completely; ℃ in a drying oven for 12 hours, and then roasted at 500-550℃ for 5 hours; the calcined powder was crushed to 20-40 mesh with a tablet machine under a pressure of 10Mpa, and 10%Mn-7%La/ ZSM-5 catalyst.

Catalyst evaluation

According to the evaluation method of Example 1, the conversion curves of the catalyst to NO and C ₃ H ₆ at different temperature points are shown in Fig. 4 . The conversion rate and operating window temperature of the optimum activation temperature are shown in Table 1.

Examples 13-18

The difference from Example 1 is that the auxiliary agent La is added, and the content of the auxiliary agent La is different. Other processes are the same as in Example 1, specifically as follows: Weigh 1.8276g of Mn(NO ₃ ) ₂ ·4H ₂ O and 0.031g -0.623g of La(NO ₃ ) ₄ 6H ₂ O, mixed and stirred until dissolved; added 2g of ZSM-5 molecular sieves for immersion for 40min; then stirred in a water bath at 75-85°C until the water evaporated completely; then the prepared powder was placed in Dry in a drying oven at 100-120°C for 12 hours, and roast at 500-550°C for 5 hours; use a tablet machine to crush the calcined powder to 20-40 mesh under a pressure of 10Mpa, and then obtain Mn with different La contents. - La/ZSM-5 catalyst.

Catalyst evaluation

According to the evaluation method of Example 1, the conversion curves of the catalyst to NO and C ₃ H ₆ at different temperature points are shown in Fig. 5 . The conversion rate and operating window temperature of the optimum activation temperature are shown in Table 1.

Examples 19-23

The difference from Example 17 is that the additive Ce is added, and the content of Ce is different. Other processes are the same as in Example 1, specifically as follows: Weigh 1.8276g of Mn(NO ₃ ) ₂ ·4H ₂ O, 0.436g of La( NO ₃ ) ₄ ·6H ₂ O and 0.031-0.0434g Ce(NO ₃ ) ₄ ·6H ₂ O, mix and stir until dissolved; add 2g of ZSM-5 molecular sieve for 40min; then stir in a water bath at 75-85°C until the water evaporates complete; then place the prepared powder in a drying oven at 100-120°C for 12 hours, and then bake it at 500-550°C for 5 hours; use a tablet machine to crush the calcined powder under a pressure of 10Mpa to 20-40 The aim is to obtain Mn-La-Ce/ZSM-5 catalysts with different Ce promoter content.

Catalyst evaluation

According to the evaluation method of Example 1, the conversion curves of the catalyst to NO and C ₃ H ₆ at different temperature points are shown in Fig. 6 . The conversion rate and operating window temperature of the optimum activation temperature are shown in Table 1.

Comparative example 1-4

Compared with Example 1, the catalyst active components are different, and the content is also different, respectively Ce, Zn, Fe, Ni, other processes are the same as in Example 1, and Ce/ZSM-5, Zn/ZSM-5, Fe/ZSM-5, Ni/ZSM-5 catalysts.

Catalyst evaluation

According to the evaluation method of Example 1, the conversion curves of the catalyst to NO and C ₃ H ₆ at different temperature points are shown in Fig. 1 . The conversion rate and operating window temperature of the optimum activation temperature are shown in Table 1.

Comparative example 5-7

The difference from Example 1 is that the additives Ni, Fe, Zr are added, and the contents of the additives Ni, Fe, Zr are different. The other processes are the same as in Example 1, and Mn-Ni/ZSM- 5. Mn-Fe/ZSM-5, Mn-Zr/ZSM-5 catalysts.

Catalyst evaluation

According to the evaluation method of Example 1, the conversion curves of the catalyst to NO and C ₃ H ₆ at different temperature points are shown in Fig. 3 . The conversion rate and operating window temperature of the optimum activation temperature are shown in Table 1.

Activity evaluation results:

The specific activity evaluation results are shown in Table 1:

XRD characterization

It is found in Figure 7 that the metal-loaded molecular sieve catalysts all have the typical characteristic diffraction peaks of ZSM-5 molecular sieves, and still retain the MFI structure. This shows that after loading Mn, La, Ce and other metals, the structure of the catalyst is not damaged during the preparation process. However, no characteristic diffraction peaks of metals or metal oxides are observed in the figure, which may be due to the fact that the metal oxides of Mn, La, and Ce on the catalyst are in an amorphous form. The characteristic diffraction peaks of the catalyst after the loading of active components and additives tend to decrease gradually. This is mainly because after the metal is loaded on the catalyst, some crystal planes of ZSM-5 molecular sieve crystals are destroyed, and the relative crystallinity decreases. As a result, the intensity of the diffraction peak corresponding to the crystal plane decreases.

Claims (10)

1. A Mn-La-Ce catalyst for selective catalytic reduction of NO and its application, comprising carrier, supported active component Mn and auxiliary agent, characterized in that: the mass of carrier is 100%, and the mass of said Mn is 100%. Min content is 5%-25%. 2. A Mn-La-Ce catalyst for selective catalytic reduction of NO according to claim 1, characterized in that: the carrier is a molecular sieve with an MFI framework. 3. A Mn-La-Ce catalyst for selective catalytic reduction of NO according to claim 2, characterized in that: the carrier is ZSM-5. 4. according to the Mn-La-Ce catalyst of a kind of selective catalytic reduction NO described in any one of claims 1-3, it is characterized in that: take carrier mass as 100%, the mass percent of active component Mn is 5 %~25%. 5. A Mn-La-Ce catalyst for selective catalytic reduction of NO according to claim 4, characterized in that: the mass percentage of the active component Mn is 20% with the carrier mass as 100%. 6. according to the Mn-La-Ce catalyst of a kind of selective catalytic reduction NO described in any one of claims 1-5, it is characterized in that: catalyst also contains auxiliary agent, and described auxiliary agent is one of La, Ce one or two. 7. according to the Mn-La-Ce catalyst of a kind of selective catalytic reduction NO described in claim 6, it is characterized in that: described auxiliary agent is Le and Ce, and described catalyst is Mn-La-Ce/ZSM- 5. 8. according to the Mn-La-Ce catalyst of a kind of selective catalytic reduction NO described in claim 7, it is characterized in that: take carrier mass as 100%, the mass percentage of La is 0.5%-10%, Ce The mass percentage composition is 0.5%～7%; The catalyst is: (5%-25%)Mn·(0.5%-10%)La·(0.5%-7%)Ce/ZSM-5. 9. according to the Mn-La-Ce catalyst of a kind of selective catalytic reduction NO described in claim 8, it is characterized in that: described catalyst is: 20%Mn-(5%-7%)La-(3%-5%)Ce/ZSM-5. 10. The application of the Mn-La-Ce catalyst for selective catalytic reduction of NO according to any one of claims 1-9 in the denitrification reaction of automobile exhaust.