NOx storage and reduction in lean burn vehicle emission control: a catalytic engineer's playground

[摘要] The reduction of NOx (NO + NO2) in lean burn vehicle exhaust is the latest challenge for catalytic engineers to meet increasingly stringent emissions standards. The lean NOx trap (LNT) is an adsorptive catalytic reactor in which NOx is stored as nitrates in excess O2 and then reduced during a brief regeneration. The multi-functional Pt-based LNT catalyst must carry out NO oxidation, NOx storage, and NOx reduction, all within a 1–2 min cycle and achieve >95% NOx conversion. This review describes studies of the transient coupling between reaction and transport, and links between catalyst composition, structure, NOx conversion, and selectivity to N2 and NH3. A glimpse is offered of emerging lean NOx reduction technologies and the new challenges they pose.

[学科分类] 工业化学