A series of materials Ce_0.3＋xZr_0.6－xY_0.1O_1.95 were prepared by co-precipitation route, and these materials were used to prepare low noble metal Pt＋Rh/Ce_0.3＋xZr_0.6－xY_0.1O_1.95＋Al₂O₃ three way cata-lysts. The properties of the series of catalysts were studied by S_BET, temperature programmed reduction and X-ray diffraction. It was found that the reducibility was closely related to the catalytic performance, and the reducibility of the catalysts containing low cerium content oxygen storage material was better than that of the catalysts containing high cerium content oxygen storage material. The catalytic performance of the catalysts containing low cerium content oxygen storage material was better than that of the catalysts containing high cerium content oxygen storage material. The catalyst Pt＋Rh/Ce_0.35Zr_0.55Y_0.1O_1.95＋Al₂O₃ possessed the best catalytic performance (the light-off temperature for HC, CO and NO conversion was 235, 175 and 200 ℃, respectively). After 1000 ℃ hydrothermal aging, the re-ducibility and catalytic performance were dropped, the thermal stability of the catalysts containing low ce-rium content oxygen storage material was better than that of the catalysts containing high cerium content oxygen storage material, and Pt＋Rh/Ce_0.35Zr_0.55Y_0.1O_1.95＋Al₂O₃ was the best.

Key words: oxygen storage material, cerium/zirconium ratio, temperature programmed reduction, three way catalyst