An environmentally-benign CeO2-TiO2 catalyst for the selective catalytic reduction of NOx with NH3 in simulated diesel exhaust

摘要

A Ce-Ti based (CeO2-TiO2) catalyst prepared by an optimized homogeneous precipitation method showed excellent NH3-SCR activity, high N-2 selectivity, broad operation temperature window, and high resistance to space velocity (even under a high gas hourly space velocity (GHSV) of 500,000 h(-1)). Compared with V2O5-WO3/TiO2 and Fe-ZSM-5 catalysts, the CeO2-TiO2 catalyst showed better catalytic performance for NH3-SCR. Under a more realistic condition of simulated diesel engine exhaust, the monolith catalyst of CeO2-TiO2 showed over 90% NOx conversion from 250 to 450 degrees C under a GHSV of 20,000 h(-1) in the presence of H2O, CO2, and C3H6. The high dispersion of active CeO2 on TiO2 in the process of homogenous precipitation and the synergistic effects between CeO2 and TiO2 in CeO2-TiO2 are important reasons for the high NH3-SCR activity. (C) 2011 Elsevier B.V. All rights reserved.