Low-content and highly effective zoned Rh and Pd three-way catalysts for gasoline particulate filter potentially meeting Euro 7

The next-generation Euro 7 standard proposed much lower pollutant limits from gasoline vehicles, spe-cifically for CO and NOx, which would be challenging for the three-way catalysts (TWCs) utilized commercially to eliminate these pollutants. TWCs with reductive (Rh) and oxidative (Pd) active compo-nents on gasoline particulate filters (TWC on GPF) play importantly auxiliary roles in the remediation of CO and NOx downstream the close coupled TWCs to meet their emission targets. Here, a low-content Rh-based TWC (0.17 wt%) zoned with a less expensive Pd-based TWC (0.29 wt%) for GPF applications (cGPF) is re-ported using improved colloidal deposition method. The supporting of Rh on Y-stabilized ZrO2 rather than on CeO2-ZrO2 inhibits the formation of inactive Ce rhodate species, while Pd on CeO2-ZrO2 not only guarantees the high oxygen storage capacity (OSC) but also enhances catalytic activity. The layout of the front one -fifth in volume being 0.29 wt% Pd on Ce0.43Zr0.57O2 and the rear four -fifths being 0.17 wt% Rh on Zr0.85Y0.15O2 prevents the possible alloying of Rh with Pd. The highly effective zoned Rh and Pd TWCs show synergistic three-way activity before and after severe hydrothermal aging at 1000 & DEG;C with 10% water for 24 h, which could be potential choices for close coupled GPF application to satisfy the upcoming stringent emission standards, such as Euro 7 and China 6b.& COPY; 2023 Chinese Society of Rare Earths. Published by Elsevier B.V. All rights reserved.

Automated summary

The next-generation Euro 7 standard proposes lower pollutant limits for gasoline vehicles, which could be challenging for commercially used three-way catalysts. This article reports a low-content Rh-based three-way catalyst and a Pd-based three-way catalyst for gasoline particulate filters, which show potential for meeting strict emission standards.