Abstract: Provided is a new catalyst that can have heightened purification performance for NOx under lean conditions. Proposed is an exhaust gas purification catalyst composition provided with: a carrier (A) comprising zirconium phosphate; a catalyst active component (a) supported on the carrier (A); a carrier (B) comprising an inorganic oxide porous body; and a catalyst active component (b) supported on the carrier (B).

Abstract: The disclosed exhaust gas purification catalyst carrier includes a modified aluminum borate which contains aluminum borate and at least one addition element selected from the group consisting of a rare earth element and an alkaline earth metal and which has an electronegativity of 2.732 or lower.

Abstract: The present invention proposes a new exhaust gas purifying catalyst in which gas diffusibility and miscibility in a catalyst layer are high, and thereby excellent catalyst performance can be exhibited. There is proposed an exhaust gas purifying catalyst comprising a catalyst layer comprising two or more types of inorganic porous particles each having a different particle size, a catalytically active component, and voids, wherein; as a first characteristic, 50% or more by number of all the voids in the catalyst layer satisfies a condition of the following (formula 1); L/2/(?S)1/2?2??(formula 1) wherein S represents a void cross-sectional area, and L represents a void cross-sectional circumference in the (formula 1), and; as a second characteristic, in the void cross-sectional area in the catalyst layer, the average void radius, determined assuming that the void shape is a perfect circle, is 10 ?m to 20 ?m.