Influence of BaO on the catalytic properties and durability of Pd-CZLA for automobile exhaust

Abstract

Liqiang QI, Mengmeng LIU, Jingxin LI, Pan ZHANG, Fang ZENG

Co-precipitation was used to prepare CeO2-ZrO2-La2O3 (CZL) support, and impregnation was employed to load nano-aluminum sol and Pd to prepare a Pd-CZLA catalyst that can be directly used in car exhaust pipe for the secondary purification of exhaust gas. The specific surface area of the catalyst can reach 143.2 m2/g. At 400 0 C, the catalytic efficiency of the catalyst was 76.47%, 70.59%, and 75.41% for C3H8, CO, and NOx, respectively. After modification through doping with 8% BaO in nano-alumina, the catalyst has enhanced high-temperature stability and maintained its high catalytic activity after aging at 1100 0 C. Scanning electron micrograph showed that the high-temperature sintering of the catalyst is slowed down when modified by BaO addition. Combined barium oxide and nano-alumina acts as a stabilizer that prevents the crystalline phase transition of alumina at high temperature and further stabilizes its structure. This material also stabilizes Pd dispersion and improves CZA supportive protection at high temperature.

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