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 CeO2@Ce-O-P multi-core@shell catalysts were synthesized in this paper for selective catalytic reduction (SCR) of NO with NH3. The experimental results had showed that CeO2@Ce-O-P-30:3 yielded best SO2 tolerance of an over 70% deNO(x) efficiency at 250 degrees C in the presence of 100 ppm SO2 for 20 h, which was much higher compared to pure Ce-O-P and CeO2 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 SO2, thereby protecting the active sites from SO2 poisoning. Especially, O-2-TPD results illustrated that a great amount of active oxygen species were retained on used CeO2@CeO-P catalyst after a long term reaction. The synergetic effect of multi-core@shell structure could be attributed to such enhanced performances. The core CeO2 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 SO2 on the catalyst. This work could provide a new way to increase the sulfur resistance for low temperature SCR catalysts. (C) 2018 Elsevier B.V. All rights reserved.