Adsorption of NO (or NH3) +O2 over the Commercial SCR Catalyst Characterized by EPR

The adsorption of reactants over the commerciallized SCR catalyst surface was investigated by EPR, as well as the influence of H
₂
O and SO
₂
. The results showed that the V
⁴⁺
over the catalyst could be oxidized under NO + O
₂
atmosphere, and NH
₃
was adsorbed on Brönsted acid sites. The amounts of V
⁴⁺
and super oxide ions were promoted at the presence of H
₂
O and SO
₂
after adsorption. However, the intensity of Fe
³⁺
decreased when H
₂
O and SO
₂
were present, indicating the favorable effect of Fe
³⁺
for anti-poisoning.