Method for preparing active aluminia coating and three-effect catalyst on foamed conducting ceramic

Abstract

One kind of three-effect catalyst for the purification of tail gas of vehicle consists of active component and carrier, the active component is selected from Ce, Zr and Pd and the carrier is foamed conducting ceramic with loaded gammma-Al2O3, silicon carbide and silica. Electrically heated foamed ceramic carrier is adhered to gamma-Al2O3 powder by using hydrolytic ethyl silicate liquid and catalyst is loaded to the electrically heated foamed ceramic carrier. The present invention has the advantages of simple technological process, being suitable for industrial production, low cost and wide application range.

Description

technical field [0001] The invention relates to a preparation method of a gas purification catalyst. Background technique [0002] With the development of world science and technology and economy, automobiles have become a symbol of modern civilized society and an integral part of modern society. One of the main sources of pollution. In order to control the emission of automobile pollutants and protect the environment in which human beings live, many countries have successively formulated and promulgated automobile exhaust emission standards, and the standards are becoming more and more stringent. Taking European emission regulations as an example, they have been issued One of the four standards is stricter than the other. The current regulations are the European No. 2 standard, and the European No. 3 standard will be implemented soon. To meet the requirements of the standard, in addition to adopting the internal control technology to reduce pollutants, the installation of ...

AI Technical Summary

Problems solved by technology

To meet the requirements of the standard, in addition to adopting the internal control technology to reduce pollutants, the installation of three-way catalyst is the main external purification method for exhaust gas purification. Due to the use of precious metals and mature preparation technology, the existing three-way Efficient catalysts can basically meet the current emission regulations, but it is a bit incapable to meet the upcoming Euro 3 and Euro 4 standards, because the core of Euro 3 and Euro 4 standards is to reduce cold start pollution, and also It is to reduce the emission of pollutants during the period from the start of the car to the activation of the catalyst. Since the temperature of the catalyst is low during this period of 2 to 3 minutes, it is difficult for the catalyst to effectively purify the exhaust gas. This problem cannot be solved simply by adding precious metals regardless of cost. Solved, most of the electric heating catalysts in research and development use metal as the carrier of the catalyst

Although the metal carrier has the advantages of good electrical conductivity and high flexibility, its many shortcomings are also obvious: the resistance of the metal carrier is too low (up to 10 -2 order of magnitude), only a special power supply that is not used in vehicles can withstand the large current generated under a certain heating power; the active coating is prepared by etching and oxidation, and the preparation process is complicated; the metal carrier can withstand high temperature for a long time , poor anti-oxidation and anti-corrosion performance; the preparation process of the metal carrier is complicated and the cost is high