Exhaust gas purification catalyst

An exhaust gas purification catalyst comprising a phosphorus collection layer and a catalyst layer containing at least one precious metal element Mp selected from the group consisting of Pt, Pd, and Rh,

• wherein the phosphorus collection layer is arranged on the upper layer side and/or the upstream side with respect to the catalyst layer;
• the phosphorus collection layer comprises a composite oxide containing Al and an alkaline earth metal element Ma that includes Mg and at least one selected from the group consisting of Ca, Sr, and Ba other than Mg, and having a cubic spinel structure belonging to the space group Fd-3m;
• the composite oxide has a molar ratio (Ma/Al molar ratio) of the Ma element to the Al element in a range of 0.02 or more and 0.60 or less;
• the composite oxide has a peak derived from the cubic spinel structure belonging to the space group Fd-3m of the composite oxide between a diffraction angle 2θxMaO that is a position of a peak derived from an alkaline earth metal oxide MaO and a diffraction angle 2θxAl2O3 that is a position of a peak derived from an aluminum oxide Al2O3 in an X-ray diffraction spectrum of the composite oxide;
• and
• the alkaline earth metal element other than Mg has a content of 10 atm % or less in terms of an elemental composition percentage relative to the total amount of Mg and the alkaline earth metal element other than Mg contained in the composite oxide.