Adsorbent for HC in exhaust gas, and process for producing the same

摘要

An adsorbent for HC in an exhaust gas is an agglomerate of double-structure particles, each of which includes an HC-adsorbing zeolite core, and a ceramic coat wrapping the zeolite core and having a plurality of through-pores communicating with a plurality of pores in the zeolite core. Each of the double-structure particles is at least one of a double-structure particle including the zeolite core comprising a single zeolite particle, and a double-structure particle including the zeolite core comprising a plurality of zeolite particles. Each of the through-pores in the ceramic coat has such a shape that the HC is easy to flow into the through-pore and difficult to flow out of the through-pore.