Effect of Fe2O3 on ZrTiO4 support for NH3-SCR catalytic performance

Abstract

The selective catalytic reduction (SCR) NH₃ catalyst is mainly used in industrial production and automobile exhaust cleaning. In this study, a novel α%Fe₂O₃/ZrTiO₄ (α=0, 8, 12, 15) catalyst was prepared by the coprecipitation impregnation method. The results show that the NO_x conversion rate of 12%Fe₂O₃/ZrTiO₄ catalyst with the optimal composition is high above 80% at 250−400 °C, close to 100% at 300 °C, and N₂ selectivity is high above 90% at 200−450 °C. The redox properties, surface acidity, and O_β/(O_α + O_β) ratio of ZrTiO₄ catalysts are improved after loading Fe₂O₃ on the ZrTiO₄ surface, which is attributed not only to the porous structure of α%Fe₂O₃/ZrTiO₄ catalyst but also to the synergistic interaction between the active component Fe₂O₃ and the support ZrTiO₄. In addition, in-situ DRIFT reactions show that the NH₃-SCR reaction of 12%Fe₂O₃/ZrTiO₄ catalyst follows the Eley-Rideal mechanism. A clear reaction mechanism is conducive to a deeper understanding of the reaction process of NO_x conversion during SCR. This work provides a feasible strategy for Fe-based SCR catalysts to replace V-based catalysts in the medium temperature range in the future.