Electrically assisted NO x storage-reduction catalytic processes enable efficient NO x purification at low temperatures

Lean-burn engines emit low CO2, but produce high NOx, and conventional three-way catalysts cannot purify NOx from oxygen-rich exhaust gases. NOx storage reduction (NSR) is effective but typically requires fuel-consuming “rich spikes”. We investigated an NSR process in an electric field, achieving effective NOx reduction under low-temperature (473 K) lean conditions. We developed a 0.1wt%Pd/0.5wt%Pt−16wt%BaO/CeO2 catalyst, where trace Pd addition suppressed C3H6 over-oxidation and enhanced its efficiency as a reductant. Applying an electric field (6 mA) significantly increased the conversion of stored NOx to N2 from 3.0% to 45.1%. This system offers a promising pathway for efficient NOx purification in hybrid vehicles by utilising surplus electricity rather than additional fuel.