Poisoning Effects of Phosphorus, Potassium and Lead on V2O5-WO3/TiO2 Catalysts for Selective Catalytic Reduction with NH3

The poisoning effect of single elements on commercial V2O5-WO3/TiO2 catalysts has been studied in the past decades. In this study, the combined effects of two multi-element systems (phosphorus-potassium and phosphorus-lead) on V2O5-WO3/TiO2 catalysts were studied by diverse characterizations. The results show that potassium and lead can result in the deactivation of catalysts to different degrees by reacting with active acid sites and reducing the amount of V5+. However, phosphorus displays slight negative influence on the NOx conversion of the catalyst due to the comprehensive effect of reducing V5+ amount and generating new acid sites. The samples poisoned by phosphorus-potassium and phosphorus-lead have higher NOx conversion than that by potassium or lead, because doped potassium or lead atoms may react with new acid sites generated by phosphate, which liberates more V-OH on the surface of catalysts and reduces the poisoning effects of potassium or lead on vanadium species and active oxygen species.