NOx reduction against alkali poisoning over Ce(SO4)2-V2O5/TiO2 catalysts by constructing the Ce4+–SO42− pair sites

Commercial V2O5-based catalysts have been successfully applied in NH3 selective catalytic reduction (NH3-SCR) of NOx from power stations, but their poor alkali-resistance restrains the wider application in nonelectrical industries. In this study, NOx reduction against alkali poisoning over V2O5/TiO2 is greatly improved via Ce(SO4)2 modification. It has been originally demonstrated that Ce4+–SO42− pair sites play crucial roles in improving NOx reduction against alkali poisoning over V2O5/TiO2 catalysts. The strong interaction between V species and Ce sites of Ce4+–SO42− pairs triggers the reaction between NH4+ species and gaseous NO via Eley-Rideal (E-R) reaction pathway. After K-poisoning, the SO42− sites of Ce4+–SO42− pairs as protective sites strongly bond with K and thus maintain the high reaction efficiency via the E-R reaction pathway. This work demonstrates an effective strategy to enhance NOx reduction against alkali poisoning over catalysts via constructing Ce4+–SO42− pair sites, contributing to developing alkali-resistant SCR catalysts for practical application in nonelectrical industries.