Deactivation mechanism of potassium additives on Ti _0.8Zr _0.2Ce _0.2O _2.4 for NH ₃-SCR of NO

Potassium additives slightly decreased catalytic activity for NH ₃-SCR of NO when the mass amount of K ₂O was less than 1.0%, but dramatically decreased the catalytic activity when the mass amount of K ₂O was more than 3.0%. The deactivation mechanism was that potassium additives directly decreased the specific surface area, the total acid amount and the acid strength of the strong acid sites, and induced the KCl-rich crystallization and the formation of non-active K ₂ZrO ₃, K ₂TiO ₃ and K ₂CeO ₃.