Promotion effect of H2 on the low temperature activity of the selective reduction of NO by light hydrocarbons over Ag/Al2O3

The effect of H2 on the selective reduction of NO by light hydrocarbons over Ag/Al2O3 catalyst under lean-exhaust conditions was investigated. The NO reduction activity at the low temperature region was markedly increased by adding H2. The NO reduction activity at high GHSV condition and SO2 tolerance were also improved by adding H2. Since the NO was reduced little by H2 in the absence of C3H8, H2 should act as a promoter of NO reduction by hydrocarbons over Ag/Al2O3. The results of reaction studies and in situ IR experiments showed that the possible reasons for promoting the effect by H2 on the HC-SCR were mainly caused by the activation of hydrocarbons.