Revealing the Promotion Effects of Nb on Alkali Resistance of FeVO₄/TiO₂ Catalysts for NO_x Reduction

Abstract

FeVO 4 -based catalysts with a wide temperature window and high SO 2 tolerance have attracted increasing attention for the selective catalytic reduction of NO x with NH 3 . However, the alkali-resistance of FeVO 4 -based catalysts is still challenging. In this study, the K-resistance of FeVO 4 /TiO 2 was markedly improved via the Nb modification. It was demonstrated that the adsorption and reactivity of NH 3 /NH 4 + and NO x species on K poisoned FeVO 4 /TiO 2 both decreased, which restrained the process of Langmuir-Hinshelwood reaction path. As a compar-ison, more adsorption of NH 3 /NH 4 + species and the higher reactivity with gaseous NO maintain the process of Eley-Rideal reaction path, leading to a satisifactory SCR activity. This work demonstrated an effective route to improve alkali-resistance via modulating reactivity and reaction path of adsorbed NH 3 /NH 4 + and NO x species over Nb modified vanadate catalysts, which presented a new point for the development of high-performance alkali-resistant SCR catalysts.

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

“…The introduction of niobium effectively enhances the surface acidity and alkali-resistance, thereby making niobium oxides a commonly employed modifier for facilitating the NH 3 -SCR reaction. 21 Our group previously found that the intense V–Nb–Ti interaction present in the 1V/Nb 0.15 Ti 0.85 catalyst is conducive to the low-temperature NH 3 -SCR activity. 22 Therefore, in this study, an NbTi composite oxide was utilized as the support to facilitate the NH 3 -SCR activity of FeVO 4 at low temperatures.…”