Novel FeVO4 catalyst modified with NbTiOx for efficient selective catalytic reduction of NOx with NH3

Abstract

FeVO₄ has garnered significant attention as a catalyst for the selective catalytic reduction of NO_x with NH₃ (NH₃-SCR). However, its limited temperature window curtails its broader applicability. In this work, FeVO₄ in various mass percentages was loaded on a NbTi composite oxide. The 9FeV/NbTi (9.0 wt% FeVO₄) catalyst showed excellent catalytic activity, with NO_x conversion beyond 90% in the temperature range from 224 to 454 °C. The introduction of the NbTi composite oxide enlarged the specific surface area of FeVO₄. Moreover, 9FeV/NbTi showed stronger redox ability, a higher proportion of surface-adsorbed oxygen, and greater abundance of acid sites than FeVO₄, thus facilitating the NH₃-SCR reaction. Furthermore, it has been observed that the Langmuir–Hinshelwood mechanism takes place on 9FeV/NbTi, while the NH₃-SCR reaction on FeVO₄ follows the Eley–Rideal mechanism. Adsorbed NO_x species participate in the NH₃-SCR reaction on 9FeV/NbTi, thereby enhancing the de-NO_x efficiency. This study provides a novel FeVO₄-based catalyst, which holds promising practical application potential in the NH₃-SCR field.