Unexpected Redox Role of WO <sub>3</sub> in V <sub>2</sub> O <sub>5</sub> ‐WO <sub>3</sub> /TiO <sub>2</sub> Catalysts for Selective Reduction of NO by Forming V–W Dinuclear Sites
Zhuocan Li, Rucheng Duan, Xin Wang, Yu Fu, Meng Gao, Hongwei Li, Guangzhi He, Hong He
Abstract
Abstract Promoters can greatly improve the activity of catalysts; however, the mechanism by which they interact with the primary catalyst to enhance catalytic activity is not always clear. It has been widely demonstrated that WO 3 in V 2 O 5 ‐WO 3 /TiO 2 catalysts acts as a promoter to enhance the surface acidity and regulate the dispersion of active V 2 O 5 species, while it is believed that the redox process takes place entirely at the V sites in the selective catalytic reduction of NO x with NH 3 (NH 3 ‐SCR). Here, by combining in situ spectroscopic measurements and density functional theory (DFT) calculations, we validate that the WO 3 directly participates in the oxidative activation of NH 3 , and hence explicitly exerts a redox effect in NH 3 ‐SCR by forming V–W dinuclear sites with V 2 O 5 . This study sheds new light on a long‐standing puzzle regarding the role of WO 3 as a promoter and hence advances the understanding of the working principle of V 2 O 5 ‐WO 3 /TiO 2 catalysts.