The enhanced resistance to P species of an Mn-Ti catalyst for selective catalytic reduction of NOx with NH3 by the modification with Mo

Abstract

Phosphorous has a deactivation effect on an SCR catalyst. In this study, the effect of Mo modification on the resistance to P species of a Mn-Ti catalyst for selective catalytic reduction of NOx with NH3 was investigated. It was found that the addition of Mo could greatly improve the P species tolerance of the Mn-Ti catalyst. From the characterization results of BET, XRD, H2-TPR, NH3-TPD and XPS, it could be concluded that the modification of the Mn-Ti catalyst by Mo could enhance its specific surface area, redox ability and NH3 adsorption capacity, along with the generation of more surface chemisorbed oxygen species, as a result, greatly enhancing the P species resistance of the Mn-Ti catalyst. The results of an in situ DRIFT study indicated that the NH3-SCR reactions over Mn-Ti and Mn-Mo-Ti catalysts were governed by L-H mechanism (≤200 °C) and E-R mechanism (>200 °C) respectively.