EXHAUST GAS PURIFICATION CATALYST

摘要

Provided is a technique that is advantageous in improving NO X -purifying performance after a long-term use. An exhaust gas-purifying catalyst (1) includes first particles of oxygen storage material (31), second particles of one or more rare-earth elements other than cerium and/or compounds thereof (32) interposed between the first particles (31), and third particles of one or more precious metal elements (33) interposed between the first particles (31), wherein a spectrum of a characteristic X-ray intensity for one of the rare-earth element(s) and a spectrum of a characteristic X-ray intensity for one of the precious metal element(s) that are obtained by performing a line analysis using energy-dispersive X-ray spectrometry along a length of 500 nm have a correlation coefficient of 0.68 or more.