Hydrogen promotes the selective catalytic reduction of NOx by ethanol over Ag/Al2O3

To understand the effect of H2 on the selective catalytic reduction of NOx with C2H5OH over Ag/Al2O3, surface intermediates were examined using in situ DRIFTS spectra, and by-products were identified using GC–MS. Results showed that H2 addition promoted the partial oxidation of C2H5OH to form enolic species, and enhanced the reaction of NCO with NO + O2 at low temperature. We propose that the enhancement of the enolic species was the main contributor in accelerating NOx reduction under the presence of H2 over Ag/Al2O3 at low temperatures.