Solid-state electrochemical cells can be used to sense and reduce NO from combustion exhaust gases. In the reduction process the products are N-2 and O-2. For these cells to be effective in fuel-lean combustion exhaust, cathode materials with high selectivity for NO vs. O-2 are necessary. Numerous compositions of La(1-x)A(x)B(1-y)B(y)'O3-delta (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 electrocatalyrically reduce NO in NO/He and simulated exhaust atmospheres. An enhanced electrocatalytic three-way activity for NO, reduction was demonstrated that increases the window of operation into fuel-lean conditions.