Role of silicotungstic acid on the catalytic performance over CeO2-HSiW catalysts for selective catalytic reduction of NOx with NH3

The CeO2 modified by silicotungstic acid (impregnation method [SiW/CeO2] and one pot method [CeO2-Si-W]) was investigated in the NH3-SCR reaction. The surface nitrate species and surface acid sites were improved by the introduction of silicotungstic acid into CeO2, 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(WO4)(3) at CeO2-Si-W, resulting in the abundance of unsaturated W=O, which contributed to the generation of Bronsted acid sites and was responsible for the superior SCR performance. Thus, CeO2-Si-W exhibited the best NOx conversion and nearly 100% NOx conversion was obtained at 225-450 degrees C.

Automated summary

CeO2 modified by silicotungstic acid showed superior performance in NH3-SCR reaction, achieving efficient NOx conversion by improving surface nitrate species and acid sites.