Abstract
In the three-way catalysts (TWCs), the ability to reduce exhaust-gas emissions is insufficient to cope with real driving conditions such as low temperature below 0°C. To improve the activity of TWCs, our study focused on the exhaust-gas purification performance and the sintering characteristics of platinum-group metal (PGM: palladium, rhodium, and platinum) particles aged at 1000°C. From our extensive analysis of mass-production catalysts covering a wide range of PGM loading amount, it was clarified that the catalysts with enlarged PGM particles after severe aging had higher turnover number than fresh catalysts. Moreover, the purification performance was affected significantly by PGM loading amount. Especially, rhodium catalysts having loading amount more than 4.0 g/L showed high catalytic performance.
