Integrated automobile tail gas purification three-way catalyst and preparation method thereof

Abstract

The invention discloses an integrated automobile tail gas purification three-way catalyst and a preparation method thereof. The catalyst includes a first carrier cordierite honeycomb ceramic, a second carrier aluminum source and an active component. The second carrier aluminum source and the active component form a coating of the catalyst, wherein the active component is a composite metal oxide. The preparation method particularly includes following steps: coating the first carrier cordierite honeycomb ceramic, which is corroded by an acid, with the aluminum source through a microwave heating technology; coating the carriers with a salt solution of the active component through an impregnation method; and performing a drying and roasting process to obtain the catalyst. The catalyst is free of usage of precious metals such as platinum, palladium, rhodium and the like, is low in cost, is stable and uniform in coating distribution, is low in initiation temperature, is wide in activity temperature window, is good in a high-temperature-resistant thermal stability and has a good application prospect.

Description

technical field

[0001] The invention belongs to the field of air pollution control and environmental protection catalytic materials, and in particular relates to an integral three-way catalyst for automobile tail gas purification and a preparation method thereof. Background technique

[0002] With the increase in the use of automobiles, a large number of automobile exhaust emissions pose a serious threat to the ecological environment and become the main factor affecting urban air pollution. The installation of automobile exhaust purification device is the main means to control exhaust pollution. The three-way catalyst is the core part of the device, which can catalyze and purify CO, HC and NO in automobile exhaust at the same time. X Three harmful gases. At present, the active components of three-way catalysts can be divided into three categories: noble metals, metals or metal oxides, and ion-exchanged zeolites. Noble metal catalysts have poor selectivity and narrow active...

Examples

Embodiment 1

[0030] (1) Put the first carrier cordierite honeycomb ceramics into 20% glacial acetic acid solution, boil in a water bath at 80°C for 2 hours, wash the surface layer and residual acid in the pores with water after cooling to neutral, and dry in an oven at 120°C for 2 hours h and above are reserved.

[0031] (2) Mix 2.7 g aluminum powder with 300 mL, 1 mol / L nitric acid solution, heat in a water bath at 100°C for 1 h, cool and filter, concentrate the filtrate to 100 mL, and add dropwise to 1 mol / L at a rate of 10 mL / min Add 10 mL of 1 mol / L nitric acid solution to ammonia water, then stir in a water bath at 85°C for 6 h to make a sol.

[0032] (3) Impregnate the first carrier cordierite honeycomb ceramics treated in step (1) into the sol in step (2), and use a box-type microwave oven reactor to heat and impregnate for 10 minutes at 40°C and 200W power. After heating, take it out, blow off the remaining sol in the channel, dry at 120°C for 2 hours, and bake at 550°C for 4 hour...

Embodiment 2

[0044] An integral three-way catalyst for automobile exhaust purification TWC-1, with cordierite honeycomb ceramics as the first carrier, γ-Al 2 o 3 is the second carrier, indium, silver, nickel, cerium composite metal oxide is the active component, and the second carrier and the active component constitute the coating of the catalyst; the mass percentage of cordierite honeycomb ceramics is 81.2%, and the coating mass The percentage content is 18.8%, and the mass percentage content of active components in the total coating amount is 4% indium, 4% silver, 2% nickel, and 1% cerium.

[0045] The catalyst is prepared according to the following steps: Put the pre-cut cube-shaped first carrier cordierite honeycomb ceramics into 20% oxalic acid solution, boil in a water bath at 80°C for 2 hours, wash the surface layer and the residual acid solution in the pores with water after cooling To neutrality, dry in an oven at 120°C for more than 2 h for later use; (2) Mix 2.7 g of aluminum ...

Embodiment 3

[0047] An integral three-way catalyst for automobile exhaust purification TWC-2, with cordierite honeycomb ceramics as the first carrier, γ-Al 2 o 3 is the second carrier, indium, silver, nickel, cerium composite metal oxide is the active component, and the second carrier and the active component constitute the coating of the catalyst; the mass percentage of cordierite honeycomb ceramics is 82.1%, and the coating mass The percentage content is 17.9%, and the mass percentage content of active components in the total coating is 5% indium, 2% silver, 2% nickel, and 1% cerium.

[0048] The catalyst is prepared according to the following steps: put the pre-cut cube-shaped first carrier cordierite honeycomb ceramic into 15% nitric acid solution, boil in a water bath at 100°C for 5 hours, and wash the surface layer and residual acid in the pores with water after cooling To neutrality, dry in an oven at 100°C for more than 4 h for later use; (2) Mix 2.7 g of aluminum powder with 300 ...

technical field

[0001] The invention belongs to the field of air pollution control and environmental protection catalytic materials, and in particular relates to an integral three-way catalyst for automobile tail gas purification and a preparation method thereof. Background technique

[0002] With the increase in the use of automobiles, a large number of automobile exhaust emissions pose a serious threat to the ecological environment and become the main factor affecting urban air pollution. The installation of automobile exhaust purification device is the main means to control exhaust pollution. The three-way catalyst is the core part of the device, which can catalyze and purify CO, HC and NO in automobile exhaust at the same time. X Three harmful gases. At present, the active components of three-way catalysts can be divided into three categories: noble metals, metals or metal oxides, and ion-exchanged zeolites. Noble metal catalysts have poor selectivity and narrow active...

Examples

Embodiment 1

[0030] (1) Put the first carrier cordierite honeycomb ceramics into 20% glacial acetic acid solution, boil in a water bath at 80°C for 2 hours, wash the surface layer and residual acid in the pores with water after cooling to neutral, and dry in an oven at 120°C for 2 hours h and above are reserved.

[0031] (2) Mix 2.7 g aluminum powder with 300 mL, 1 mol / L nitric acid solution, heat in a water bath at 100°C for 1 h, cool and filter, concentrate the filtrate to 100 mL, and add dropwise to 1 mol / L at a rate of 10 mL / min Add 10 mL of 1 mol / L nitric acid solution to ammonia water, then stir in a water bath at 85°C for 6 h to make a sol.

[0032] (3) Impregnate the first carrier cordierite honeycomb ceramics treated in step (1) into the sol in step (2), and use a box-type microwave oven reactor to heat and impregnate for 10 minutes at 40°C and 200W power. After heating, take it out, blow off the remaining sol in the channel, dry at 120°C for 2 hours, and bake at 550°C for 4 hour...

Embodiment 2

[0044] An integral three-way catalyst for automobile exhaust purification TWC-1, with cordierite honeycomb ceramics as the first carrier, γ-Al 2 o 3 is the second carrier, indium, silver, nickel, cerium composite metal oxide is the active component, and the second carrier and the active component constitute the coating of the catalyst; the mass percentage of cordierite honeycomb ceramics is 81.2%, and the coating mass The percentage content is 18.8%, and the mass percentage content of active components in the total coating amount is 4% indium, 4% silver, 2% nickel, and 1% cerium.

[0045] The catalyst is prepared according to the following steps: Put the pre-cut cube-shaped first carrier cordierite honeycomb ceramics into 20% oxalic acid solution, boil in a water bath at 80°C for 2 hours, wash the surface layer and the residual acid solution in the pores with water after cooling To neutrality, dry in an oven at 120°C for more than 2 h for later use; (2) Mix 2.7 g of aluminum ...

Embodiment 3

[0047] An integral three-way catalyst for automobile exhaust purification TWC-2, with cordierite honeycomb ceramics as the first carrier, γ-Al 2 o 3 is the second carrier, indium, silver, nickel, cerium composite metal oxide is the active component, and the second carrier and the active component constitute the coating of the catalyst; the mass percentage of cordierite honeycomb ceramics is 82.1%, and the coating mass The percentage content is 17.9%, and the mass percentage content of active components in the total coating is 5% indium, 2% silver, 2% nickel, and 1% cerium.

[0048] The catalyst is prepared according to the following steps: put the pre-cut cube-shaped first carrier cordierite honeycomb ceramic into 15% nitric acid solution, boil in a water bath at 100°C for 5 hours, and wash the surface layer and residual acid in the pores with water after cooling To neutrality, dry in an oven at 100°C for more than 4 h for later use; (2) Mix 2.7 g of aluminum powder with 300 ...

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