Synthesis of Sulfur-Resistant TiO 2 -CeO 2 Composite and Its Catalytic Performance in the Oxidation of a Soluble Organic Fraction from Diesel Exhaust

摘要

Sulfur poisoning is one of the most important factors deteriorating the purification efficiency of diesel exhaust after-treatment system, thus improving the sulfur resistibility of catalysts is imperative. Herein, ceria oxygen storage material was introduced into a sulfur-resistant titania by a co-precipitation method, and the sulfur resistibility and catalytic activity of prepared TiO 2 -CeO 2 composite in the oxidation of diesel soluble organic fraction (SOF) were studied. Catalytic performance testing results show that the CeO 2 modification significantly improves the catalytic SOF purification efficiency of TiO 2 -CeO 2 catalyst. SO 2 uptake and energy-dispersive X-ray (EDX) results suggest that the ceria doping does not debase the excellent sulfur resistibility of bare TiO 2 , the prepared TiO 2 -CeO 2 catalyst exhibits obviously better sulfur resistibility than the CeO 2 and commercial CeO 2 -ZrO 2 -Al 2 O 3 . X-ray powder diffraction (XRD) and Raman spectra indicate that cerium ions can enter into the TiO 2 lattice and not form complete CeO 2 crystals. X-ray photoelectron spectroscopy (XPS), H 2 -temperature programmed reduction (H 2 -TPR) and oxygen storage capacity (OSC) testing results imply that the addition of CeO 2 in TiO 2 -CeO 2 catalyst can significantly enhance the surface oxygen concentration and oxygen storage capacity of TiO 2 -CeO 2 .