Role of silicotungstic acid on the catalytic performance over CeO 2 ‐HSiW catalysts for selective catalytic reduction of NO x with NH 3

The CeO 2 modified by silicotungstic acid (impregnation method [SiW/CeO 2 ] and one pot method [CeO 2 ‐Si‐W]) was investigated in the NH 3 ‐SCR reaction. The surface nitrate species and surface acid sites were improved by the introduction of silicotungstic acid into CeO 2 , which stopped forming stable nitrate, and then improved the N 2 selectivity. The interaction between Ce and W species existed and caused the formation of Ce 2 (WO 4 ) 3 at CeO 2 ‐Si‐W, resulting in the abundance of unsaturated W=O, which contributed to the generation of Brønsted acid sites and was responsible for the superior SCR performance. Thus, CeO 2 ‐Si‐W exhibited the best NO x conversion and nearly 100% NO x conversion was obtained at 225–450°C.