화학공학소재연구정보센터
Catalysis Today, Vol.29, No.1-4, 71-75, 1996
Development of High-Performance, Pd-Based, 3 Way Catalysts
The use of Pd in three-way catalytic (TWC) converters of automobiles presents serious limitations which are related to sintering, poisoning and excessive selectivity for HC and CO oxidation, making NOx reduction difficult. In the present work, an advanced automotive exhaust catalyst design is applied which reduces, to a large extent, these shortcomings of Pd. This catalyst is based on dispersion of Pd on YSZ (ZrO2 stabilized with 8 mol-% Y2O3) forming the internal layer of a three-layer washcoat. The external layers contain small quantities of Pt and Ph dispersed on suitable supports, such as gamma-Al2O3 and W6+-doped TiO2, respectively. This scheme offers a high performance TWC with low light-off temperature for the conversion of all three pollutants (GO, HC and NOx), enhanced poisoning tolerance and improved thermal resistance.