Influence of alumina-supported M-Pt catalysts in DeNOx reactions with M = Pd or Ir or Ru

To better understand N-2 formation in the selective catalytic reduction of NOx by propene under oxidative atmosphere, we studied the catalytic behavio r of bimetallics. Surface segregation phenomena may provoke geometric and e lectronic modifications of the catalytic active sites. To explain our resul ts we invoked: (i) the facile way to oxidize the bimetallic aggregates, (ii ) the presence of atoms with low coordination number able to be oxidized fi rst and (iii) an eventual formation of like "vic-diNO(x) species" on such b imetallics leading to N-2 formation.