CN107115888A - A kind of preparation method and its usage of the catalyst of Cu SSZ 13 - Google Patents

Abstract

The invention provides a preparation method and application of Cu-SSZ-13 catalyst. The preparation method comprises the following steps: 1) putting raw materials silicon source, aluminum source, template agent, and crystal seed into a mortar and grinding them into a uniform mixture; 2) putting the mixture into a reaction kettle for crystallization, cooling, washing and drying, and then roasting , to obtain Na-SSZ-13 molecular sieve carrier; 3) preparing ammonium nitrate solution and adding Na-SSZ-13 molecular sieve carrier, filtering, washing and drying after ion exchange to obtain _NH4 -SSZ-13 molecular sieve; 4)) preparing nitric acid The copper solution is added with NH ₄ ‑SSZ‑13 molecular sieves, filtered, dried and calcined after ion exchange to prepare the Cu‑SSZ‑13 catalyst. The Cu-SSZ-13 catalyst of the present invention has excellent NH ₃ -SCR catalytic activity, N ₂ selectivity, hydrothermal stability and anti-H ₂ O and SO ₂ poisoning performance, and is suitable for purifying diesel vehicle exhaust.

Description

A kind of preparation method and application of Cu-SSZ-13 catalyst

technical field

The invention relates to the technical field of catalysts, in particular to a preparation method and application of a Cu-SSZ-13 catalyst.

Background technique

At present, the selective catalytic reduction of NOx (NH ₃ -SCR) using NH ₃ as the reducing agent has been widely used in the purification of diesel vehicle exhaust due to its high NOx conversion rate, good fuel economy, and simple engine control. The catalyst is core of the technology. Among them, V ₂ O ₅ -WO ₃ (MoO ₃ )/TiO ₂ catalysts have been used industrially for many years, but there are still some disadvantages, such as narrow operating temperature window, low selectivity of N ₂ at high temperature, active component V has biological toxicity, Harm the ecological environment and human health. Other developed non-V catalysts, such as oxide catalysts Ce-W, Fe-Ti, and Cu-based or Fe-based molecular sieve catalysts supported by ZSM-5, beta, etc., have narrow temperature operating windows and poor hydrothermal stability to varying degrees. And HC poisoning ability is poor and so on. Therefore, it is a great challenge to develop catalysts with high catalytic activity, wide temperature operating window and high hydrothermal stability.

In recent years, Cu-SSZ-13 catalysts have attracted extensive attention due to their high catalytic activity and high hydrothermal stability. At present, the commonly used method for preparing Cu-SSZ-13 catalyst is liquid phase ion exchange method, but the preparation of SSZ-13 support by this method requires the use of expensive template N, N, N-trimethyladamantane ammonium hydroxide, which is not conducive to the Large-scale promotion and application of catalysts. In order to reduce the production cost of the catalyst, the technology of preparing Cu-SSZ-13 with cheap templates such as Cu-TEPA complexes or choline chloride has also received extensive attention, but the Cu-SSZ-13 catalyst prepared by it has The hydrothermal stability still needs to be further improved. At the same time, the crystallization process of all preparation methods is completed in a liquid phase environment, which not only produces sewage in the preparation process, but also has a low yield. Therefore, it is of great significance to prepare the Cu-SSZ-13 catalyst with higher activity and better hydrothermal stability by using a new and cheap template agent under anhydrous conditions, which is of great significance for the removal of mobile source exhaust gas and environmental protection.

Contents of the invention

Aiming at the deficiencies of the prior art, one of the objects of the present invention is to provide a method for preparing Cu-SSZ-13 catalyst. The prepared Cu-SSZ-13 catalyst has excellent NH ₃ -SCR catalytic activity, _N2 selectivity, hydrothermal stability and resistance to _H2O and _SO2 poisoning.

For reaching this purpose, the present invention adopts following technical scheme:

A kind of preparation method of Cu-SSZ-13 catalyst, comprises the steps:

1) Put the raw materials silicon source, aluminum source, templating agent and seed crystal into a mortar, and grind them into a uniform mixture;

2) Put the homogeneous mixture of step 1) into a reactor for crystallization, cool, wash and dry, and then roast to obtain a Na-SSZ-13 molecular sieve carrier;

3) Prepare an ammonium nitrate solution, add the Na-SSZ-13 molecular sieve carrier prepared in step 2), filter, wash, and dry after ion exchange to obtain NH ₄ -SSZ-13 molecular sieve;

4) Prepare a copper nitrate solution, add the NH ₄ -SSZ-13 molecular sieve prepared in step 3), filter, dry and roast after ion exchange to obtain a Cu-SSZ-13 catalyst.

In step 1), the silicon source is sodium silicate and SiO ₂ , the aluminum source is aluminum sulfate, the template is N,N,-dimethyl-N-ethylcyclohexylammonium bromide, the The seed crystal is H-SSZ-13;

Preferably, the effective components of the raw materials are based on Na ₂ O, SiO ₂ , Al ₂ O ₃ , N,N,-dimethyl-N-ethylcyclohexyl ammonium bromide, H-SSZ-13, which The dosage is as follows: the molar ratio of the Na ₂ O to the SiO ₂ is (0.18-0.26):1, for example, the molar ratio of the Na ₂ O to the SiO ₂ is 0.18:1, 0.19:1, 0.2: 1. 0.21:1, 0.22:1, 0.23:1, 0.24:1, 0.25:1, 0.26:1.

Preferably, the molar ratio of SiO ₂ to Al ₂ O ₃ is (18-24):1, for example, the molar ratio of SiO ₂ to Al ₂ O ₃ is 18:1, 19:1, 20:1, 21:1, 22:1, 23:1, 24:1.

Preferably, the molar ratio of the N,N,-dimethyl-N-ethylcyclohexyl ammonium bromide to the SiO ₂ is (0.1-0.18):1, for example, the N,N,-dimethyl Base-N-ethylcyclohexyl ammonium bromide and described SiO Molar ratio is 0.1: _1,0.11 :1,0.12:1,0.13:1,0.14:1,0.15:1,0.16:1,0.17: 1. 0.18:1.

Preferably, the mass percentage of H-SSZ-13 accounting for the total weight of raw materials is 1-10%, for example, the mass percentage of H-SSZ-13 accounting for the total weight of raw materials is 1%, 2%, 3%, 4% , 5%, 6%, 7%, 8%, 9%, 10%.

In step 2), the crystallization temperature is 160-220°C, such as 160°C, 170°C, 180°C, 190°C, 200°C, 210°C, 220°C; the crystallization time is 3-8d ( day), such as 3d, 4d, 5d, 6d, 7d, 8d.

In step 2), the cooling temperature is 23-27°C, such as 23°C, 24°C, 25°C, 26°C, 27°C.

Preferably, the specific process of the washing is to wash with deionized water until the mixture is neutral.

Preferably, the drying temperature is 100° C., and the drying time is 12 hours.

In step 2), the temperature of the calcination is 500-800°C, for example, the temperature of the calcination is 500°C, 550°C, 600°C, 650°C, 700°C, 750°C, 800°C; the time of the calcination is 4 to 8 hours, for example, the time of the calcination is 4 hours, 5 hours, 6 hours, 7 hours, 8 hours.

In step 3), the concentration of the ammonium nitrate solution is 0.5-1.5 mol/L, such as 0.5 mol/L, 0.7 mol/L, 1.0 mol/L, 1.2 mol/L, 1.5 mol/L.

In step 3), the amount of the Na-SSZ-13 molecular sieve carrier per 50 mL of the ammonium nitrate solution is 1 g.

In step 3), the temperature of the ion exchange is 70-85°C, such as 70°C, 71°C, 72°C, 73°C, 74°C, 75°C, 76°C, 77°C, 78°C, 79°C, 80°C , 81°C, 82°C, 83°C, 84°C, 85°C.

In step 4), the concentration of the copper nitrate solution is 0.01～0.5mol/L, such as 0.01mol/L, 0.05mol/L, 0.1mol/L, 0.15mol/L, 0.2mol/L, 0.25mol/L , 0.3mol/L, 0.35mol/L, 0.4mol/L, 0.45mol/L, 0.5mol/L.

In step 4), the amount of the NH ₄ -SSZ-13 molecular sieve used in every 50-200 mL of the copper nitrate solution is 1 g.

In step 4), the ion exchange temperature is 23-27°C, such as 23°C, 24°C, 25°C, 26°C, 27°C.

In step 4), the temperature of the calcination is 500-800°C, for example, the temperature of the calcination is 500°C, 550°C, 600°C, 650°C, 700°C, 750°C, 800°C; the time of the calcination is 4 to 8 hours, for example, the time of the calcination is 4 hours, 5 hours, 6 hours, 7 hours, 8 hours.

The second object of the present invention is to provide a Cu-SSZ-13 catalyst prepared by the above preparation method.

The third object of the present invention is to provide a method for purifying diesel vehicle exhaust, which uses the above-mentioned Cu-SSZ-13 catalyst.

Compared with prior art, the beneficial effect of the present invention is:

(1) The Cu-SSZ-13 catalyst prepared by the solid phase synthesis method of the present invention has high catalytic activity, especially in the temperature range of 200-450° C., and the NO _x conversion rate is above 80%.

(2) The Cu-SSZ-13 catalyst prepared by the solid-phase synthesis method of the present invention has excellent resistance to high space velocity, and in the range of 250-450°C, it still maintains a high _NOx conversion rate at 800,000h ^-1 , The conversion of _NOx is greater than 80%.

(3) The Cu-SSZ-13 catalyst prepared by the solid-phase synthesis method of the present invention has excellent _N2 generation selectivity, and the _N2 generation selectivity is greater than 95% in the entire temperature range of 150-550 °C.

(4) The preparation method of the present invention improves the crystallinity and the silicon-aluminum ratio of the catalyst while obtaining the high activity of the Cu-SSZ-13 catalyst. The silicon-aluminum ratio is about 11, which improves the hydrothermal stability of the catalyst.

(5) The Cu-SSZ-13 catalyst of the present invention still maintains a conversion rate of more than 80% in the range of 225-450° C. after being aged at 800° C. for 16 hours, and is suitable for purification of diesel vehicle exhaust.

(6) The Cu-SSZ-13 catalyst of the present invention is prepared by using non-toxic components, which will not cause harm to human health and ecological environment; the preparation method is simple and easy to operate, without waste water pollution, and the yield is >90%.

Description of drawings

Fig. 1 is the Cu-SSZ-13 catalyst of different Cu loadings prepared by the solid-phase synthesis method of the present invention and the Cu _10.9 -SSZ-13 catalyst prepared by the one-step synthesis method of Comparative Example 1, and the Na-SSZ-13 catalyst prepared by Example 1. 13 Schematic diagram of the XRD pattern of the catalyst;

Fig. 2 is the schematic diagram of the catalytic activity of the Cu-SSZ-13 catalyst of different Cu loads that the solid-phase synthesis method of the present invention makes;

Fig. 3 is that the Cu-SSZ-13 catalyst of different Cu loads that solid _- phase synthesis method of the present invention makes is to N selectivity schematic diagram;

Figure 4 shows the Cu-SSZ-13 catalysts with different Cu loadings prepared by the solid phase synthesis method of the present invention and the Cu-SSZ-13 catalysts with different Cu loadings prepared by the one-step synthesis method in Comparative Example 2-3 after hydrothermal aging Schematic diagram of catalytic activity after treatment;

Fig. 5 is the schematic diagram of the catalytic activity of the Cu-SSZ-13 catalyst prepared by the solid-phase synthesis method of the present invention under different space velocity conditions;

Fig. 6 is a schematic diagram of the catalytic activity of the Cu-SSZ-13 catalyst prepared by the solid-phase synthesis method of the present invention in the presence of H ₂ O and SO ₂ .

detailed description

In order to facilitate understanding of the present invention, the present invention enumerates the following examples. It should be clear to those skilled in the art that the embodiments are only for helping to understand the present invention, and should not be regarded as specific limitations on the present invention.

Example 1

The preparation process of the Na-SSZ-13 molecular sieve carrier of this embodiment is as follows: 1.412g of sodium silicate, 1.368g of silicon dioxide, 0.65g of aluminum sulfate, 0.8g of N,N,-dimethyl-N -Ethylcyclohexylammonium bromide template and 0.05g of seed crystal H-SSZ-13 were put into a mortar for grinding, and after being evenly ground, they were placed in a reaction kettle for crystallization at 180°C for 5 days, and then suction filtered and washed. Put the filter cake in an oven at 100°C overnight, and finally bake it in air at 600°C for 6 hours to obtain a Na-SSZ-13 molecular sieve carrier.

Example 2

The preparation process of the Cu-SSZ-13 catalyst in this example is as follows: Stir the Na-SSZ-13 molecular sieve carrier prepared in Example ₁ and 1mol/L _NH4NO3 solution at 80°C for 5h, and then pump again The NH ₄ -SSZ-13 powdered molecular sieve was obtained through the procedures of filtration, washing and drying. The prepared NH ₄ -SSZ-13 molecular sieve and 0.1mol/L Cu(NO ₃ ) ₂ solution were stirred at room temperature for 24 hours, and then the Cu-SSZ-13 powder was obtained by suction filtration, washing, drying, and roasting. shape catalyst. The prepared catalyst is pressed into tablets, ground, sieved, and 40-60 meshes are taken for later use. Catalysts with different Cu loadings were adjusted by the number of ion exchange of Cu(NO ₃ ) ₂ solution. In this example, a Cu _1.7 -SSZ-13 catalyst with a Cu loading of 1.7% was prepared through one ion exchange.

Example 3

The preparation process of the Cu-SSZ-13 catalyst in this example is as follows: Stir the Na-SSZ-13 molecular sieve carrier prepared in Example ₁ and 1mol/L _NH4NO3 solution at 80°C for 5h, and then pump again The NH ₄ -SSZ-13 powdered molecular sieve was obtained through the procedures of filtration, washing and drying. The prepared NH4-SSZ-13 molecular sieve and 0.1mol/L Cu(NO ₃ ) ₂ solution were stirred at room temperature for 24 hours, and then filtered, washed, dried and roasted to obtain Cu-SSZ-13 powder catalyst. The prepared catalyst is pressed into tablets, ground, sieved, and 40-60 meshes are taken for later use. Catalysts with different Cu loadings were adjusted by ion exchange times of Cu(NO ₃ ) ₂ solution. In this example, Cu _2.2 -SSZ-13 catalysts with Cu loadings of 2.2% by mass were prepared through 2 ion exchanges.

Example 4

The preparation process of the Cu-SSZ-13 catalyst in this example is as follows: Stir the Na-SSZ-13 molecular sieve carrier prepared in Example ₁ and 1mol/L _NH4NO3 solution at 80°C for 5h, and then pump again The NH ₄ -SSZ-13 powdered molecular sieve was obtained through the procedures of filtration, washing and drying. The prepared NH4-SSZ-13 molecular sieve and 0.1mol/L Cu(NO ₃ ) ₂ solution were stirred at room temperature for 24 hours, and then filtered, washed, dried and roasted to obtain Cu-SSZ-13 powder catalyst. The prepared catalyst is pressed into tablets, ground, sieved, and 40-60 meshes are taken for later use. Catalysts with different Cu loadings were adjusted by ion exchange times of Cu(NO ₃ ) ₂ solution. In this example, Cu _2.8 -SSZ-13 catalysts with Cu loadings of 2.8% by mass were obtained through 3 ion exchanges.

Comparative example 1

The Cu-SSZ-13 catalyst of this comparative example was prepared by a one-step synthesis method, and the preparation process was as follows: firstly, 0.514g NaAlO ₂ was dissolved in 4.722g deionized water, and then 1.149g CuSO ₄ ·H ₂ O was added. After stirring for 0.5h, add 1.07g of TEPA dropwise, add 1.1g of NaOH after fully stirring, and then add 3.33mL of silica sol (31wt.%) after stirring for 0.5h, stir for 2 to 3h, and put it into a Teflon-lined steel Reactor, and react at a temperature of 100 ℃ for 4d. After the reaction, the product was washed with deionized water, dried at 100°C for 12 hours, and calcined at 600°C for 6 hours to obtain a Cu _10.9 -SSZ-13 catalyst with a Cu loading of 10.9% by mass.

Comparative example 2

The Cu-SSZ-13 catalyst of this comparative example was prepared by a one-step synthesis method, and the preparation process was as follows: firstly, 0.514g NaAlO ₂ was dissolved in 4.722g deionized water, and then 1.149g CuSO ₄ ·H ₂ O was added. After stirring for 0.5h, add 1.07g of TEPA dropwise, add 1.1g of NaOH after fully stirring, and then add 3.33mL of silica sol (31wt.%) after stirring for 0.5h, stir for 2 to 3h, and put it into a Teflon-lined steel Reactor, and react at a temperature of 100 ℃ for 4d. After the reaction, the product was washed with deionized water and dried at 100°C for 12 hours to obtain a Cu-SSZ-13 _initial sample. 1 g of Cu-SSZ-13 _initial was added to 100 mL of HNO ₃ (0.1 mol/L) solution, and exchanged in a water bath at 80°C for 12 hours to obtain a Cu _5.6 -SSZ-13 catalyst with a Cu loading of 5.6% by mass.

Comparative example 3

The Cu-SSZ-13 catalyst of this comparative example was prepared by a one-step synthesis method, and the preparation process was as follows: firstly, 0.514g NaAlO ₂ was dissolved in 4.722g deionized water, and then 1.149g CuSO ₄ ·H ₂ O was added. After stirring for 0.5h, add 1.07g of TEPA dropwise, add 1.1g of NaOH after fully stirring, and then add 3.33mL of silica sol (31wt.%) after stirring for 0.5h, stir for 2 to 3h, and put it into a Teflon-lined steel Reactor, and react at a temperature of 100 ℃ for 4d. After the reaction, the product was washed with deionized water and dried at 100°C for 12 hours to obtain a Cu-SSZ-13 _initial sample. 1g of Cu-SSZ-13 _initial was added into 100mL of HNO ₃ (0.3mol/L) solution, and exchanged in a water bath at 80°C for 12h to obtain a Cu _3.6 -SSZ-13 catalyst with a Cu loading of 3.6% by mass.

The catalysts prepared by Examples 2-4 of the present invention and Comparative Examples 1-3 are used for the purification of diesel vehicle exhaust, wherein the usage of the catalysts is 50 mg respectively, and the composition of the reaction mixture is: [NO]=[NH ₃ ]=500ppm, [O ₂ ]=5%, N ₂ as balance gas, the total gas flow rate is 500mL/min, the corresponding space velocity is 200,000h ^-1 , 400,000h ^-1 , 800,000h ^-1 , the reaction temperature is 150- 550°C. NO and NH ₃ as well as by-products N ₂ O and NO ₂ were measured by infrared gas cell.

Carry out XRD analysis to the Na-SSZ-13 catalyst that embodiment 1 makes, the Cu-SSZ-13 catalyst of different Cu loads that embodiment 2-4 makes and the Cu _10.9 -SSZ-13 catalyst that comparative example 1 makes , the XRD spectrum is shown in Figure 1. As can be seen from Fig. 1, with respect to the Cu _10.9 -SSZ-13 catalyzer synthesized by the one-step synthetic method of comparative example 1, the Na-SSZ-13 molecular sieve carrier of the present invention and the prepared Cu-SSZ-13 catalyzer have higher crystallinity.

The Cu-SSZ-13 catalysts with different Cu loads prepared in Examples 2-4 of the present invention are used for the purification of diesel vehicle exhaust, and its catalytic activity is compared under the condition of 400,000h ^-1 at a space velocity, and the experimental results as shown in picture 2. It can be seen from Fig. 2 that the prepared Cu-SSZ-13 molecular sieve catalyst has a wide temperature window, and the NOx conversion rate is above 80% in the temperature range of 200-450°C.

The Cu-SSZ-13 catalysts with different Cu loadings prepared in Examples _2-4 of the present invention are used for the purification of diesel vehicle exhaust, and their selectivity to N is compared under the condition that the space velocity is 400,000h ^-1 , the experimental results are shown in Figure 3. It can be seen from Figure 3 that the prepared Cu-SSZ-13 catalysts with different Cu loadings have higher selectivity to _N2 , all of which are above 95%.

The Cu-SSZ-13 catalysts with different Cu loadings prepared in Examples 2-4 of the present invention and the Cu-SSZ-13 catalysts with different Cu loadings prepared in one-step synthesis in Comparative Example 2-3 were subjected to severe hydrothermal Aging treatment, that is, pass the above catalyst into the air containing 10wt% water at a temperature of 800°C for 16 hours, then use the above catalyst after treatment to purify diesel vehicle exhaust, and compare the catalytic activity results as shown in Figure 4 Show. It can be seen from FIG. 4 that, compared with Comparative Examples 2-3, the Cu-SSZ-13 catalysts with different Cu loadings prepared in Examples 2-4 of the present invention exhibit excellent hydrothermal stability.

The Cu _2.2 -SSZ-13 catalyst prepared in Example 3 was tested for its catalytic activity under different space velocities, that is, the space velocities were 200,000h ^-1 , 400,000h ^-1 , 800,000h ^-1 , and the test results As shown in Figure 5. It can be seen from Figure 5 that even at a space velocity of 800,000 h ^-1 , the Cu-SSZ-13 catalyst prepared by the solid phase synthesis method of the present invention still maintains excellent catalytic activity.

The catalytic activity of the Cu _2.2 -SSZ-13 catalyst prepared in Example 3 was tested under the condition of containing H ₂ O and SO ₂ , and the test results are shown in FIG. 6 . It can be seen from Fig. 6 that even in the presence of H ₂ O and SO ₂ , the Cu-SSZ-13 catalyst prepared by the solid phase synthesis method of the present invention still maintains excellent catalytic activity.

In summary, the Cu-SSZ-13 catalyst prepared by the solid phase synthesis method of the present invention has very high _NOx activity, excellent _N2 selectivity and hydrothermal stability in the whole temperature range of 150-550°C , very suitable for catalytic purification of nitrogen oxides in diesel vehicle exhaust.

The applicant declares that the present invention illustrates the detailed process equipment and process flow of the present invention through the above-mentioned examples, but the present invention is not limited to the above-mentioned detailed process equipment and process flow, that is, it does not mean that the present invention must rely on the above-mentioned detailed process equipment and process flow process can be implemented. Those skilled in the art should understand that any improvement of the present invention, the equivalent replacement of each raw material of the product of the present invention, the addition of auxiliary components, the selection of specific methods, etc., all fall within the scope of protection and disclosure of the present invention.

Claims (10)

1. a kind of preparation method of Cu-SSZ-13 catalyst, it is characterised in that comprise the following steps：

1) raw material silicon source, silicon source, template, crystal seed are put into mortar, grind to form uniform mixture；

2) by step 1) uniform mixture be fitted into crystallization in reactor, Na-SSZ-13 is made in cooling washing dry roasting Molecular sieve carrier；

3) prepare ammonium nitrate solution, add step 2) made from Na-SSZ-13 molecular sieve carriers, after ion exchange cross diafiltration Wash, dry, NH is made₄- SSZ-13 molecular sieves；

4) prepare copper nitrate solution, add step 3) made from NH₄- SSZ-13 molecular sieves, filter, dry, roast after ion exchange Burn, Cu-SSZ-13 catalyst is made.

2. preparation method according to claim 1, it is characterised in that step 1) in, the silicon source is sodium metasilicate, SiO₂, institute Silicon source is stated for aluminum sulfate, the template is N, N, and-dimethyl-N-ethyl cyclohexyl ammonium bromide, the crystal seed is H-SSZ-13；

Preferably, the active principle of the raw material is with Na₂O、SiO₂、Al₂O₃, N, N ,-dimethyl-N-ethyl cyclohexyl ammonium bromide, H-SSZ-13 is counted, and its consumption is as follows：The Na₂The O and SiO₂Mol ratio be (0.18~0.26):1；

Preferably, the SiO₂With the Al₂O₃Mol ratio be (18~24):1；

Preferably, N, the N ,-dimethyl-N-ethyl cyclohexyl ammonium bromide and the SiO₂Mol ratio be (0.1~0.18): 1；

Preferably, the mass percent that the H-SSZ-13 accounts for raw material gross weight is 1~10%.

3. preparation method according to claim 1 or 2, it is characterised in that step 2) in, the temperature of the crystallization is 160 ~220 DEG C, the time of the crystallization is 3~8d.

4. the preparation method according to one of claim 1-3, it is characterised in that step 2) in, the temperature of the cooling is 23~27 DEG C；

Preferably, the detailed process of the washing be washed with deionized to mixture for neutrality；

Preferably, the temperature of the drying is 100 DEG C, and the time of the drying is 12h.

5. the preparation method according to one of claim 1-4, it is characterised in that step 2) in, the temperature of the roasting is 500~800 DEG C, the time of the roasting is 4~8h.

6. the preparation method according to one of claim 1-5, it is characterised in that step 3) in, the ammonium nitrate solution Concentration is 0.5~1.5mol/L.

7. the preparation method according to one of claim 1-6, it is characterised in that step 3) in, ammonium nitrate described in per 50mL The consumption of Na-SSZ-13 molecular sieve carriers described in solution is 1g；

Preferably, step 3) in, the temperature of the ion exchange is 70~85 DEG C；

Preferably, the detailed process of the washing be washed with deionized to mixture for neutrality；

Preferably, the temperature of the drying is 100 DEG C, and the time of the drying is 12h.

8. the preparation method according to one of claim 1-7, it is characterised in that step 4) in, the copper nitrate solution Concentration is 0.01~0.5mol/L；

Preferably, step 4) in, NH described in copper nitrate solution described in every 50~200mL₄The consumption of-SSZ-13 molecular sieves is 1g；

Preferably, step 4) in, the temperature of the ion exchange is 23~27 DEG C；

Preferably, step 4) in, the temperature of the roasting is 500~800 DEG C, and the time of the roasting is 4~8h.

9. the Cu-SSZ-13 catalyst that a kind of preparation method as described in one of claim 1-8 is prepared.

10. a kind of purification method of exhaust gas from diesel vehicle, it is characterised in that the purification method is using as claimed in claim 9 Cu-SSZ-13 catalyst.