Electrocatalytic reduction of NOx on La1−xAxB1−yB′yO3−δ: evidence of electrically enhanced activity

Solid-state electrochemical cells can be used to sense and reduce NOx from combustion exhaust gases. In the reduction process the products are N2 and O2. For these cells to be effective in fuel-lean combustion exhaust, cathode materials with high selectivity for NO vs. O2 are necessary. Numerous compositions of La1−xAxB1−yB′yO3−δ (where A is Sr or Ba; and B and B′ are transition metals) were investigated for heterogeneous catalytic activity and selectivity for NO reduction using temperature programmed reaction (TPR). Ceramic cells using these materials as cathodes were fabricated and used to electrocatalytically reduce NO in NO/He and simulated exhaust atmospheres. An enhanced electrocatalytic three-way activity for NOx reduction was demonstrated that increases the window of operation into fuel-lean conditions.