SO₂-Poisoning-Resistant CeO₂@TiO₂ Nanorod with the core–shell Structure for the Catalytic Oxidation of CO

Abstract

The core−shell-structured CeO 2 @TiO 2 nanorods and traditional CeTiO x nanoparticles were prepared to study the role of the core−shell structure in CO catalytic oxidation and SO 2 resistance. CeO 2 @TiO 2 maintained a higher than 98% CO conversion at 300 °C in the flue gas containing 1000 ppm CO and achieved about 68% CO conversion after adding 500 ppm SO 2 for 5 h. The core−shell structure mitigated the crystallinity loss of the CeO 2 core and pore blockage of CeO 2 @TiO 2 . TiO 2 avoided the reaction between SO 2 and CeO 2 to protect CeO 2 from SO 2 poisoning. In the case of SO 2 passing through the shell, TiO 2 could inhibit the formation of Ce 2 (SO 4 ) 3 , delaying the deactivation of the CeO 2 core. Furthermore, the sulfate deposited on CeO 2 @TiO 2 possessed a smaller amount and poorer thermal stability than that on CeTiO x . The design of the core−shell structure provides an effective route to enhance the SO 2 -poisoning resistance of catalysts in CO oxidation.