CeO2-TiO2 catalyst prepared by physical mixing for NH3 selective catalytic reduction: Evidence about the migration of sulfates from TiO2 to CeO2 via simple calcination

摘要

A mechanical mixture of CeO2 and TiO2 powder with a small amount of sulfate was applied for the selective catalytic reduction (SCR) of NO with NH3. After calcination at 500 oC, the mixed sample showed significantly enhanced activity and selectivity compared to the uncalcined one and, moreover, demonstrated even higher activity than the conventional V2O5/TiO2 catalyst above 300 A degrees C. Combined characterization results revealed that the main active sites were newly formed sulfate species on CeO2, the number of which increased with calcination. Temperatureresolved DRIFT spectra provided convincing evidence about the migration of sulfate species from TiO2 to CeO2, as confirmed from the shift of v(S=O) band as a result of the mechanical mixing and the subsequent calcination.