On the correlation between microstructural changes of Ag-H-ZSM-5 catalysts and their catalytic performances in the selective catalytic reduction of NOx by methane

The surface adsorbed oxygen species (Oα) participate the SCR reaction in two ways: one is oxidation of NO into active intermediates NOx (x ≥ 2); the other is catalyzing the direct combustion of CH4. The migration of surface oxygen into the bulk (Oβ) was supposed to be responsible for the different catalytic behaviors of silver entities in the CH4-SCR of NOx.