Investigation of Mg-doping effect on the activity and P tolerance of V2O5-MoO3/TiO2 catalysts for NH3-SCR

Abstract

Abstract V2O5-MoO3/TiO2 catalyst modified by Mg was studied to obtain higher NOx SCR activity and higher P, SO2 and H2O resistance than the V2O5-MoO3/TiO2. The results show that Mg modification can promote the denitration activity of V2O5-MoO3/TiO2 catalyst, and the maximum NOx removal efficiency of Mg1-SCR catalyst was 97.5%, the optimum reaction temperature and flow rate were 350℃ and 1200 ml/min, respectively. Mg doping can broaden the reaction temperature window of the catalyst, and the denitration efficiency can reach more than 87% at 300℃. P2O5 solution was prepared as poisoning precursor and mixed with catalyst to simulate the process of catalyst P-poisoning. The step-wise study showed that Mg0.5-SCR and Mg1-SCR catalyst displays higher durable resistance to P, SO2 and H2O than original catalyst. The catalysts have been characterized by XRD, BET, SEM, TEM, XPS, CO2-TPD, NH3-TPD and H2-TPR. The obtained results suggested that the Mg doping made the active components more dispersed on the surface of the supports, improved the thermal stability of the catalyst, promoted the transition of VOx from monomeric state to polymerized state, inhibited the interaction between P and V, and protected the acid site.