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 N-2. Such an improvement can be obtained using low overpotentials, applying -100 mV to the Pt catalyst-electrode enhances the selectivity to N-2 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. (C) 2003 Elsevier Science (USA). All rights reserved.