EXHAUST GAS PURIFICATION CATALYST

摘要

The present invention addresses the problem in exhaust gas purification catalysts comprising two catalysts in which a startup catalyst and an underfloor catalyst are combined, whereby a decrease in the gas diffusibility of the underfloor catalyst causes the efficiency of using a catalytic active site to be lowered and thus the purification performance to be degraded. The present invention relates to an exhaust gas purification catalyst comprising two catalysts in which a startup catalyst and an underfloor catalyst having a catalyst coat including many voids are combined, wherein a certain portion or more of all the voids are composed of pores having a high aspect ratio of 5 or greater, thereby improving the purification performance of the catalyst.