Novel Pt/Rh Coated Gasoline Particulate Filter Development and Its Application

With the stringent China6 legislation implementation in 2020, Gasoline Particulate Filters (GPF) are widely applied to control Particulate Number (PN), THC, CO, and NOx emissions from gasoline engines. The typical GPF product in the market is usually coated with a Pd/Rh three-way catalyst (TWC) layer. In this work, a novel and cost-effective GPF was achieved through Pd substitution with lower price of Pt in a novel Pt/Rh coating technology. This novel Pt/Rh GPF was evaluated for back pressure under clean and soot loaded conditions, PN Filtration efficiency and TWC activity. When compared with the commercial product of Pd/Rh GPF, the novel Pt/Rh GPF had 15% lower clean BP contribution, 25% lower back pressure with 2 g/L soot loading, while achieving equivalent PN filtration efficiency. The TWC activity of this novel Pt/Rh GPF was investigated after multiple aging including Four Mode bench aging and 1050 °C oven aging. The aged Pt/Rh GPF gave superior TWC performance when tested for light off, and oxygen storage capacity. The soot regeneration activity of Pt/Rh GPF was also discussed and it is concluded soot oxidation would be facilitated by NO2, due to the better NO oxidation activity over Pt/Rh GPF. This novel Pt/Rh coated GPF passed the technical verification by some customers in China market and was successfully applied on China6 platforms with placing the GPF in the under floor (UF) location or in the close coupled (CC) position respectively in the aftertreatment system.