Coupling catalysis to electrochemistry: a solution to selective reduction of nitrogen oxides in lean-burn engine exhausts?

The non-faradaic electrochemical modification of catalytic activity (NEMCA) was investigated in selective catalytic reduction (SCR) of NO by propene on Pt films deposited on NASICON, a Na+ conducting solid electrolyte. This study was carried out under lean-burn conditions. In such a system, electrochemical promotion is shown to strongly enhance both the catalytic activity and the selectivity to N2. Such an improvement can be obtained using low overpotentials, applying −100 mV to the Pt catalyst-electrode enhances the selectivity to N2 from 41 to 61%. The use of NASICON allows work to be done at quite low temperatures (about 300 °C) compatible with the treatment of automotive exhausts.