Ternary catalyst for automobile tail gas and its preparation method

Abstract

A three-element catalyst for cleaning the tail gas of car features that the cellular cordierite ceramics modified by the RE tailing mixture or transition metal oxide is ued as the first carrier, the internal and external modified alumina coating layers are used as the second carrier, and the noble metal Pt, Rh or Pd is used as its active component.

Description

technical field [0001] The invention relates to the treatment of automobile tail gas purification, in particular to a three-way catalyst used for automobile tail gas purification and a preparation method thereof. Background technique [0002] Automobile exhaust is the main source of air pollution worldwide, and the installation of catalytic converters is one of the most effective methods for the prevention and control of exhaust pollution. At present, the most commonly used catalytic converter is the three-way purifier, which can simultaneously purify the main harmful poisons in the three exhaust gases of NOx, CH, and CO under the condition of controlling the air-fuel ratio. The core of the three-way purifier is the three-way catalyst. [0003] Existing automobile exhaust purification catalysts generally use metal or ceramic honeycomb as the carrier, use noble metals (Pt, Pd, Rh) as active components, and transition metal elements and alkaline earth metals as auxiliary acti...

AI Technical Summary

Problems solved by technology

The disadvantage is that some precious metals will be covered by activated alumina and additives, and cannot be fully exposed to the surface of the catalyst and cannot be effectively utilized; secondly, the coating of the catalyst prepared by this method is easy to harden and brittle. Large, the compatibility between the coating and the ceramic is poor, after repeated cold and heat cycles and mechanical vibration and other shocks, the coating will eventually crack and fall off, the active components on the coating will also fall off, and the service life of the catalyst will be reduced

The disadvantage is that the process is complicated, and it takes several times of repeated dipping to achieve the required load. This is mainly due to the large water content of the aluminum glue, and the amount of one-time coating is small. If the amount of one-time coating is too large, the coating is easy to to crack

The loading of activated alumina is low, and the effective surface area provided is small, so that the active components Pt, Pd, and Rh cannot be better dispersed, which affects the activity and durability of the catalyst.

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