Abstract: A catalyst supporting honeycomb includes a pillar-shaped honeycomb structure and catalyst particles supported on the honeycomb structure. The honeycomb structure includes cell walls extending in a longitudinal direction of the honeycomb structure to define a plurality of cells extending in the longitudinal direction. The plurality of cells include large-volume cells having first opening ends and second closing ends opposite to the first opening ends along the longitudinal direction, and small-volume cells having first closed ends and second opening ends opposite to the first closed ends along the longitudinal direction. Total cross sectional areas of the large-volume cells on a plane perpendicular to the longitudinal direction are larger than total cross sectional areas of the small-volume cells on the plane. The catalyst particles include an oxide catalyst having an average particle diameter of at least about 0.05 ?m and at most about 1.00 ?m.

Abstract: A catalyst supporting honeycomb including a pillar-shaped honeycomb structure having a plurality of cells formed in parallel with one another in a longitudinal direction with a cell wall interposed therebetween, and catalyst particles supported on the honeycomb structure. The catalyst particles include an oxide catalyst, an average particle diameter of which is at least about 0.05 ?m and at most about 1.00 ?m.

Abstract: A particulate matter sensor includes a particulate matter detection filter having a volumetric soot storage capacity smaller than the volumetric soot storage capacity of a diesel particulate filter, and a differential pressure measuring part measuring a differential pressure between an inlet and an outlet of the particulate matter detection filter.