Particulate burning purifying catalyst

Abstract

To provide a particulate purification catalyst that easily burns particulates trapped in a particulate filter of a diesel vehicle at a lower temperature than conventional ones. The structure of this particulate catalyst is characterized in that it is formed by including a NO oxidation catalyst formed on a first carrier supported by a catalyst component and an NO2 decomposition catalyst formed on a second support supported by a catalyst component. Preferably, noble metals such as NO oxidation catalyst platinum are supported on the first carrier of tungstic acid / zirconia acidic substances, NO2 decomposition catalysts are selected from the transition metal group catalyst components supported on the second carrier such as titanium oxide, or NO2 decomposition catalysts At least one metal selected from alkali metals and alkaline earth metals and noble metals such as platinum are supported on a second support such as titanium oxide.

Description

Background technique [0001] The present invention relates to a catalyst for combusting and removing soot-like particles (carbonaceous fine particles) contained in exhaust gas discharged from internal combustion engines such as diesel engines. Background technique [0002] Exhaust gas from diesel engines contains particulate matter, which is one of the main causes of local air pollution. Reducing the emission of such particulate matter is an important issue to be solved early on among environmental problems. [0003] In order to reduce the emission of such particulate matter, a particulate filter is installed in the exhaust passage of the diesel engine, and once the particulates in the exhaust gas are captured, the trapped particulates are ignited and burned, and research has been conducted. However, the particles trapped on the particulate filter do not ignite at temperatures above about 600°C. In contrast, the temperature of the exhaust gas of a diesel engine is much lower...

AI Technical Summary

Problems solved by technology

[0005] However, under the actual operation of the diesel engine, the temperature of the exhaust gas is often lower than 350°C. At the above-mentioned ignition temperature of about 350°C to 400°C, the particles cannot be completely burned and removed, and the pressure loss of the exhaust gas passing through the filter is large, resulting in combustion. Barriers to fee reduction

Moreover, once a large number of remaining particles are burned, the temperature of the particle filter exceeds about 800°C, and there is a problem of premature deterioration of the particle filter.

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