The promotion effect of CeOx on Cu-SAPO-34 catalyst for selective catalytic reduction of NOx with ammonia

An incipient wetness impregnation method is employed to incorporate CeOx into a Cu-SAPO-34 catalyst prepared with a two-step ion exchange method. The addition of CeOx improves the NOx selective catalytic reduction (SCR) activity of the catalyst, and suppresses the nonselective side reactions, such as the NO oxidation and NH3 oxidation reactions in high temperature range of the catalyst. The temperature programmed reduction with H2 and the electron paramagnetic resonance results reveal that the addition of CeOx decreases the amount of the isolated Cu2+ species, which contributes to the decreases of the NO and NH3 oxidation activities of the catalyst in high temperature range and its SCR activity in low temperature range.