Autocatalytic synergism observed during lean-NOx reduction with a bifunctional reductant over Ag/Al2O3 catalyst

► An autocatalytic synergism was observed during NOx reduction with MEA over Ag/Al2O3. ► MEA transforms the single-functional Ag/Al2O3 into a dual-functional catalyst. ► Highly reactive reductants such as H2, NH3, and isocyanate species are formed by MEA. ► The kinetic synergy is attributable primarily to the formation of H-bonding in MEA.