阅读说明：本技术 一种稳定性高的汽车尾气净化催化剂的制备方法 (Preparation method of high-stability automobile exhaust purification catalyst ) 是由 胡朝稳 吕颂 花瑞富 于 2019-09-21 设计创作，主要内容包括：本发明提供一种稳定性高的汽车尾气净化催化剂的制备方法,包括载体、涂层和催化剂,所述载体为ZSM-5改性沸石分子筛,所述涂层采用纳米级γ-氧化铝,所述催化剂采用双金属ZSM-5沸石分子催化剂或单金属ZSM-5沸石分子催化剂,其制备方法包括S1制备ZSM-5改性沸石分子筛、S2制备金属ZSM-5沸石分子催化剂和S3制备稳定性高的汽车尾气净化催化剂。本发明通过采用ZSM-5改性沸石分子筛在作为催化剂载体,从而使催化剂具有较高选择性和较好的热稳定性,且催化剂失活后易再生,因此对于汽车尾气净化处理具有高效性,稳定性和节约能源的效果。(The invention provides a preparation method of an automobile exhaust purification catalyst with high stability, which comprises a carrier, a coating and a catalyst, wherein the carrier is a ZSM-5 modified zeolite molecular sieve, the coating adopts nano-grade gamma-alumina, the catalyst adopts a bimetallic ZSM-5 zeolite molecular catalyst or a monometallic ZSM-5 zeolite molecular catalyst, and the preparation method comprises the steps of preparing the ZSM-5 modified zeolite molecular sieve by S1, preparing the metal ZSM-5 zeolite molecular catalyst by S2 and preparing the automobile exhaust purification catalyst with high stability by S3. The ZSM-5 modified zeolite molecular sieve is used as a catalyst carrier, so that the catalyst has high selectivity and good thermal stability, and the catalyst is easy to regenerate after being inactivated, thereby having the effects of high efficiency, stability and energy conservation for automobile exhaust purification treatment.)

1. A preparation method of an automobile exhaust purification catalyst with high stability comprises a carrier, a coating and a catalyst, and is characterized in that: the carrier is a ZSM-5 modified zeolite molecular sieve, the coating adopts nano-grade gamma-alumina, the catalyst adopts a bimetallic ZSM-5 zeolite molecular catalyst or a monometallic ZSM-5 zeolite molecular catalyst, and the preparation method comprises the following steps:

s1 preparation of ZSM-5 modified zeolite molecular sieve: tetrapropylammonium hydroxide is used as a single template agent, silicon aluminum is used as an aluminum source, silicon dioxide is used as a silicon source, a spherical porous ZSM-5 zeolite molecular sieve is synthesized by adopting a low-temperature aging and high-temperature crystallization two-stage temperature change method, deionized water, the silicon aluminum, hydrochloric acid and the silicon dioxide are added for mixing, stirring is carried out for 30min, drying is carried out in a 150-DEG oven, and then high-temperature crystallization is carried out, so as to prepare the ZSM-5 modified zeolite molecular sieve;

s2 preparation of metallic ZSM-5 zeolite molecular catalyst: soaking a certain amount of the ZSM-5 modified zeolite molecular sieve prepared in the step S1 in one or two solutions of copper nitrate, ferric nitrate, manganese acetate, cerium nitrate or cobalt nitrate, electromagnetically stirring for 1h at the temperature of 90 ℃, centrifuging to obtain a solid, soaking the solid in a metal salt solution again, stirring for 1h under the conditions, centrifuging to obtain a solid, repeatedly exchanging for 3 times in the way, washing the finally obtained solid twice with water with the same volume under the action of ultrasound to remove physically adsorbed ions, separating the solid, and then heating from room temperature to 723K at the heating rate of 2K/min to roast for 4.5h to prepare a bimetallic ZSM-5 zeolite molecular catalyst or a monometal ZSM-5 zeolite molecular catalyst;

s3, preparing the automobile exhaust purification catalyst with high stability: pouring the ZSM-5 modified zeolite molecular sieve, the bimetallic ZSM-5 zeolite molecular catalyst or the monometallic ZSM-5 zeolite molecular catalyst, the nano gamma-alumina coating and the organic forming agent into a stirrer, mixing and stirring for pugging, repeatedly kneading by a kneader, ageing the pug, putting the pug into a forming machine for pre-extrusion to prepare catalyst pug with uniform humidity, putting the catalyst pug into the forming machine, extruding the pug into a honeycomb blank by a mould, drying and roasting to obtain the high-stability automobile exhaust purification catalyst.

2. The preparation method of the catalyst for purifying automobile exhaust with high stability according to claim 1, wherein the preparation method comprises the following steps: the molar ratio of the silicon source to the aluminum source in the step S1 is 60.

3. The preparation method of the catalyst for purifying automobile exhaust with high stability according to claim 1, wherein the preparation method comprises the following steps: the temperature of the low-temperature aging in the step S1 is less than 100 ℃, and the temperature of the high-temperature crystallization is 400-600 ℃.

4. The preparation method of the catalyst for purifying automobile exhaust with high stability according to claim 1, wherein the preparation method comprises the following steps: the mass percentages of the carrier, the catalyst and the coating are 1: 0.1% -20%: 10 to 25 percent.

5. The preparation method of the catalyst for purifying automobile exhaust with high stability according to claim 1, wherein the preparation method comprises the following steps: the monometallic ZSM-5 zeolite molecular catalyst in the step S2 is a Cu-ZSM-5 catalyst, a Fe-ZSM-5 catalyst, a Mn-ZSM-5 catalyst, a Ce-ZSM-5 catalyst or a Co-ZSM-5 catalyst.

6. The preparation method of the catalyst for purifying automobile exhaust with high stability according to claim 1, wherein the preparation method comprises the following steps: the bimetallic ZSM-5 zeolite molecular catalyst in the step S2 is a Mn-Fe/ZSM-5 catalyst or a Ce-Co/ZSM-5 catalyst.

Technical Field

The invention relates to the technical field of automobile exhaust purification catalysis, in particular to a preparation method of an automobile exhaust purification catalyst with high stability.

Background

Automobile exhaust is exhaust gas generated when an automobile is used, and contains hundreds of different compounds, wherein pollutants comprise solid suspended particles, carbon monoxide, carbon dioxide, hydrocarbons, nitrogen oxides, lead, sulfur oxides and the like. The tail gas can not only directly harm human health, but also have a profound influence on the environment of human life. The sulfur dioxide in the tail gas has strong pungent smell, and the sulfur dioxide easily causes the generation of acid rain when reaching a certain concentration, so that soil and water sources are acidified, and the growth of crops and forests is influenced.

Although the existing exhaust pipe of the automobile is internally provided with the three-way catalyst to treat the exhaust, the existing catalyst exhaust purification technology has poor purification effect and low stability of the catalyst, and needs to perform secondary purification of the exhaust outside the automobile.

Therefore, it is necessary to invent a preparation method of a catalyst for purifying automobile exhaust gas with high stability to solve the above problems

Disclosure of Invention

The invention aims to provide a preparation method of an automobile exhaust purification catalyst with high stability, so as to solve the technical problems.

In order to solve the technical problems, the invention adopts the following technical scheme:

a preparation method of an automobile exhaust purification catalyst with high stability comprises a carrier, a coating and a catalyst, wherein the carrier is a ZSM-5 modified zeolite molecular sieve, the coating adopts nanoscale gamma-alumina, the catalyst adopts a bimetallic ZSM-5 zeolite molecular catalyst or a monometallic ZSM-5 zeolite molecular catalyst, and the preparation method comprises the following steps:

s1 preparation of ZSM-5 modified zeolite molecular sieve: tetrapropylammonium hydroxide is used as a single template agent, silicon aluminum is used as an aluminum source, silicon dioxide is used as a silicon source, a spherical porous ZSM-5 zeolite molecular sieve is synthesized by adopting a low-temperature aging and high-temperature crystallization two-stage temperature change method, deionized water, the silicon aluminum, hydrochloric acid and the silicon dioxide are added for mixing, stirring is carried out for 30min, drying is carried out in a 150-DEG oven, and then high-temperature crystallization is carried out, so as to prepare the ZSM-5 modified zeolite molecular sieve;

s2 preparation of metallic ZSM-5 zeolite molecular catalyst: soaking a certain amount of the ZSM-5 modified zeolite molecular sieve prepared in the step S1 in one or two solutions of copper nitrate, ferric nitrate, manganese acetate, cerium nitrate or cobalt nitrate, electromagnetically stirring for 1h at the temperature of 90 ℃, centrifuging to obtain a solid, soaking the solid in a metal salt solution again, stirring for 1h under the conditions, centrifuging to obtain a solid, repeatedly exchanging for 3 times in the way, washing the finally obtained solid twice with water with the same volume under the action of ultrasound to remove physically adsorbed ions, separating the solid, and then heating from room temperature to 723K at the heating rate of 2K/min to roast for 4.5h to prepare a bimetallic ZSM-5 zeolite molecular catalyst or a monometal ZSM-5 zeolite molecular catalyst;

s3, preparing the automobile exhaust purification catalyst with high stability: pouring the ZSM-5 modified zeolite molecular sieve, the bimetallic ZSM-5 zeolite molecular catalyst or the monometallic ZSM-5 zeolite molecular catalyst, the nano gamma-alumina coating and the organic forming agent into a stirrer, mixing and stirring for pugging, repeatedly kneading by a kneader, ageing the pug, putting the pug into a forming machine for pre-extrusion to prepare catalyst pug with uniform humidity, putting the catalyst pug into the forming machine, extruding the pug into a honeycomb blank by a mould, drying and roasting to obtain the high-stability automobile exhaust purification catalyst.

Preferably, the molar ratio of the silicon source to the aluminum source in the step S1 is 60.

Preferably, the temperature of the low-temperature aging in the step S1 is less than 100 ℃, and the temperature of the high-temperature crystallization is 400-600 ℃.

Preferably, the mass percentages of the carrier, the catalyst and the coating are 1: 0.1% -20%: 10 to 25 percent.

Preferably, the monometallic ZSM-5 zeolite molecular catalyst in step S2 is a Cu-ZSM-5 catalyst, a Fe-ZSM-5 catalyst, a Mn-ZSM-5 catalyst, a Ce-ZSM-5 catalyst or a Co-ZSM-5 catalyst.

Preferably, the bimetallic ZSM-5 zeolite molecular catalyst in the step S2 is a Mn-Fe/ZSM-5 catalyst or a Ce-Co/ZSM-5 catalyst.

The invention has the beneficial effects that:

(1) the ZSM-5 modified zeolite molecular sieve is used as a catalyst carrier, so that the catalyst has high selectivity and good thermal stability, and the catalyst is easy to regenerate after being inactivated, thereby having the effects of high efficiency, stability and energy conservation for automobile exhaust purification treatment.

(2) According to the invention, the activity and stability of the catalyst are effectively increased and the activity and stability of the catalyst for treating the automobile exhaust are improved by adding the single metal catalyst and the bimetallic catalyst in the ZSM-5 modified zeolite molecular sieve.

Detailed Description

The present invention will be further described with reference to specific embodiments for the purpose of facilitating an understanding of technical means, characteristics of creation, objectives and functions realized by the present invention, but the following embodiments are only preferred embodiments of the present invention, and are not intended to be exhaustive. Based on the embodiments in the implementation, other embodiments obtained by those skilled in the art without any creative efforts belong to the protection scope of the present invention. The experimental methods in the following examples are conventional methods unless otherwise specified, and materials, reagents and the like used in the following examples are commercially available unless otherwise specified.