Revealing the nature of dinuclear active sites on CenTiOx catalysts for the selective catalytic reduction NOx with NH3

Abstract

A series of CenTiOx catalysts prepared by a solvothermal method was investigated on the selective catalytic reduction (SCR) of NOx with NH3. Among them, Ce0.3TiOx showed the most excellent SCR performance. Combining various characterizations with DFT calculations, it can be found that dinuclear sites, i.e., acid and redox sites, were successfully constructed on the Ce0.3TiOx surface. Specifically, pentacoordinate Ti sites served as the primary acid sites, while surface lattice O- in the adjacent Ce-O--Ce served as redox sites. Furthermore, the outstanding oxidation ability of this catalyst was crucial to active adsorbed NH3 and NHNO intermediates, which are the critical steps for the NH3-SCR reaction. Finally, a plausible NH3-SCR reaction pathway on CenTiOx catalysts was proposed.