LNT-SCR dual-layer catalysts optimized for lean NOx reduction by H2 and CO

- Adding ceria to LNT layer enhances the low-temperature deNOx efficiency.
- SCR diffusion layer in a dual-layer catalyst degrades high-temperature performance.
- Zoned LNT and SCR catalyst leads to high NOx conversion over wide temperature range.
- Optimized zoned dual-layer catalyst enables reduction of needed PGM loading.