Development of Pt –free, Perovskite based Lean NOx Trap (LNT) Catalysts
Wei Li, GM Global R&D
With a tighter regulatory environment, NOx reduction in oxygen-rich environment remains a major challenge in advanced fuel efficient engine aftertreatment systems. Here, we demonstrate strontium-doped perovskite oxides as efficient platinum substitutes in lean NOx trap (LNT) catalysts. The La-based perovskite catalysts coated on monolith substrates showed excellent activities for the NO oxidation reaction, a critical step that demands heavy usage of Pt in a current diesel aftertreatment system. Under realistic conditions, a La0.9Sr0.1MnO3-based LNT catalyst achieved comparable NOx reduction performance to a commercial Pt-based counterpart. The results show promise for a considerably lower cost diesel exhaust treatment system.