The promoting effect of CeO2@Ce-O-P multi-core@shell structure on SO2 tolerance for selective catalytic reduction of NO with NH3 at low temperature

A series of CeO 2 @Ce-O-P “multi-core@shell” catalysts were synthesized in this paper for selective catalytic reduction (SCR) of NO with NH 3 . The experimental results had showed that CeO 2 @Ce-O-P-30:3 yielded best SO 2 tolerance of an over 70% deNO x efficiency at 250 °C in the presence of 100 ppm SO 2 for 20 h, which was much higher compared to pure Ce-O-P and CeO 2 samples. Further characterization results indicated that Ce-O-P coating layer could somewhat inhibit sulfur depositing on the catalysts during SCR reaction in the presence of SO 2 , thereby protecting the active sites from SO 2 poisoning. Especially, O 2 -TPD results illustrated that a great amount of active oxygen species were retained on used CeO 2 @Ce-O-P catalyst after a long term reaction. The synergetic effect of “multi-core@shell” structure could be attributed to such enhanced performances. The “core” CeO 2 devoted abundant active oxygen sites to fulfill the SCR reaction. And the “shell” Ce-O-P could not only provide acid sites, but also protect the active oxygen species by avoiding the over-adsorption of SO 2 on the catalyst. This work could provide a new way to increase the sulfur resistance for low temperature SCR catalysts.