Patent attributes
The honeycomb catalyst body includes a honeycomb structure having porous partition walls, outflow side plugged portions, inflow side plugged portions, and catalyst layers formed on the surfaces of the partition walls on the side of the outflow cells, the cells are formed so that an open area of each outflow cell is larger than an open area of each inflow cell, a porosity of the partition walls of the honeycomb structure is from 25 to 55%, and in a cross section parallel to the extending direction of the cells, a total area of the catalyst layers formed on the surfaces of the pores in the partition walls is 5% or less of a total area of the pores in the partition walls.