Arsenic-induced deterioration of the CeWAlOx catalyst for selective catalytic reduction of NO by NH3

Abstract

This study is focused on the As-induced poisoning of CeWAlOx for the selective catalytic reduction of NO by NH3 (NH3-SCR). When the As mass ratio reached 2.89 wt%, the NO conversion decreased to below 40% in the explored temperature window from 150 to 400 °C. The fresh and poisoned catalysts are characterized by using XRF, BET, XRD, NH3-TPD, H2-TPR and in situ DRIFTS. The characterization results indicate that the poisoning by arsenic decreased BET surface area, concentration of surface acid sites, NH3 and NOx adsorbtion capability on the catalyst surface. In addition, Ce–O–As bonds may be formed, which could inhibit the activity of the CeO2. These factors appear to play the key role in the deactivation of the catalyst.