Three-dimensional composite pyrochlore ammoxidation catalyst for purifying tail gas of diesel vehicle

An exhaust gas purification, three-dimensional composite technology, applied in metal/metal oxide/metal hydroxide catalysts, physical/chemical process catalysts, chemical elements of heterogeneous catalysts, etc., can solve the problem of reducing the mass transfer efficiency of surface active free oxygen, etc. The problem is to improve the lack of active free oxygen on the surface of the material, improve the high temperature structural stability, and promote the capture effect.

Pending Publication Date: 2021-08-24
CATARC AUTOMOTIVE TEST CENT TIANJIN CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, due to the unsaturated vacancy structure lacking oxygen atoms, the mass transfer efficiency of surface-active free oxygen in thermal catalytic reactions will be reduced to a certain extent. In

Method used

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  • Three-dimensional composite pyrochlore ammoxidation catalyst for purifying tail gas of diesel vehicle
  • Three-dimensional composite pyrochlore ammoxidation catalyst for purifying tail gas of diesel vehicle
  • Three-dimensional composite pyrochlore ammoxidation catalyst for purifying tail gas of diesel vehicle

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] 1. Weighing La(NO) with a purity of 99% 3 ) 3 ·6H 2 O and Ce(NO 3 ) 3 ·6H 2 O each 0.1mol, citric acid CA (C 6 h 8 o 7 )0.05mol, urea (CH 4 N 2 O) 0.03mol was dissolved in 100mL-500mL deionized water (18MΩ) at a temperature of 40°C and stirred for 30min until clarified to obtain a precursor solution, the La of the two metal salts in the precursor solution 3+ , Ce 3+ The ratio of the ion concentration to the molecular concentration of citric acid and urea is (0.9~1.1):(0.45~0.55):(0.25~0.35); after the precursor solution is transferred to a freezer at -8°C~-12°C for quick freezing, Put it into a freeze dryer and maintain it under the vacuum condition of 0.1Pa~1Pa for 20h~24h to obtain white flocculent catalyst precursor powder;

[0037] 2. Keep the precursor powder in a blast drying oven at 180°C for 3 hours, then place it in a sintering furnace with an air atmosphere, and raise the temperature from room temperature to 250°C at a rate of 1°C / min-3°C / min and ke...

Embodiment 2

[0041] 1. Weighing La(NO) with a purity of 99% 3 ) 3 ·6H 2 O and Ce(NO 3 ) 3 ·6H 2 O each 0.1mol, citric acid CA (C 6 h 8 o 7 )0.05mol, urea (CH 4 N 2 O) 0.03mol was dissolved in 100mL-500mL deionized water (18MΩ) at a temperature of 40°C and stirred for 30min until clarified to obtain a precursor solution, the La of the two metal salts in the precursor solution 3+ , Ce 3+ The ratio of the ion concentration to the molecular concentration of citric acid and urea is (0.9~1.1):(0.45~0.55):(0.25~0.35); after the precursor solution is transferred to a freezer at -8°C~-12°C for quick freezing, Put it into a freeze dryer and maintain it under the vacuum condition of 0.1Pa~1Pa for 20h~24h to obtain white flocculent catalyst precursor powder;

[0042] 2. Keep the precursor powder in a blast drying oven at 180°C for 3 hours, then place it in a sintering furnace with an air atmosphere, and raise the temperature from room temperature to 250°C at a rate of 1°C / min-3°C / min and ke...

Embodiment 3

[0046] 1. Weighing La(NO) with a purity of 99% 3 ) 3 ·6H 2 O and Ce(NO 3 ) 3 ·6H 2 O each 0.1mol, citric acid CA (C 6 h 8 o 7 )0.05mol, urea (CH 4 N 2 O) 0.03mol was dissolved in 100mL-500mL deionized water (18MΩ) at a temperature of 40°C and stirred for 30min until clarified to obtain a precursor solution, the La of the two metal salts in the precursor solution 3+ , Ce 3+ The ratio of the ion concentration to the molecular concentration of citric acid and urea is (0.9~1.1):(0.45~0.55):(0.25~0.35); after the precursor solution is transferred to a freezer at -8°C~-12°C for quick freezing, Put it into a freeze dryer and maintain it under the vacuum condition of 0.1Pa~1Pa for 20h~24h to obtain white flocculent catalyst precursor powder;

[0047] 2. Keep the precursor powder in a blast drying oven at 180°C for 3 hours, then place it in a sintering furnace with an air atmosphere, and raise the temperature from room temperature to 250°C at a rate of 1°C / min-3°C / min and ke...

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PUM

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Abstract

The invention provides a three-dimensional composite pyrochlore ammoxidation catalyst for purifying tail gas of a diesel vehicle. The molecular formula of the catalyst is Cux-La2Ce2O7, the molar ratio of the Cu element to the La2Ce2O7 is x:100, and the value range of x is 1-10. The catalyst provided by the invention takes pyrochlore as a carrier, and has relatively good high-temperature structural stability; therefore, the integrity of the catalyst structure is prevented from being damaged by over-high exhaust emission and strong vibration of a vehicle body; moreover, the pyrochlore has a large number of lone pair A-site electrons, so that acid active sites can be quickly generated on the surface of the catalyst, and capture of ammonia gas is promoted; the Cu metal oxide is uniformly loaded on the surface of the catalyst, so that the insufficiency of active free oxygen on the surface of the material in the catalytic reaction process is effectively improved, the surface mass transfer efficiency of the catalyst is improved, and meanwhile the reaction rate of N-H bond breakage is accelerated. Compared with an original pyrochlore catalyst activity test, the result shows that the NH3 conversion rate of the pyrochlore loaded with the Cu oxide after continuous reaction for 60 hours reaches 80% or above.

Description

technical field [0001] The invention belongs to the technical field of automobile tail gas treatment, and in particular relates to a three-dimensional composite pyrochlore ammonia oxidation catalyst used for purifying diesel vehicle tail gas. Background technique [0002] In recent years, with the sharp rise of my country's economic strength and the continuous improvement of comprehensive national strength, the rapid development of traditional automobile manufacturing and transportation industries has been promoted. Diesel vehicles, as one of the core means of transportation in the transportation industry, will inevitably bring about To more serious exhaust pollution. NH 3 As one of the harmful gas pollutants at the tail end of the diesel vehicle exhaust after-treatment system, a large amount of leakage will seriously threaten the survival and development of human beings, especially the health (respiratory and nervous system diseases) and the atmospheric environment (smog po...

Claims

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Application Information

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IPC IPC(8): B01J23/83B01D53/94B01D53/58
CPCB01J23/002B01J23/83B01D53/9436B01J2523/00B01J2523/17B01J2523/3706B01J2523/3712Y02A50/20
Inventor 孔祥辰李振国邵元凯任晓宁李凯祥吴撼明吕丛杰
Owner CATARC AUTOMOTIVE TEST CENT TIANJIN CO LTD
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