Comprehensive investigation of the mutual effect of Ce and W species in the NH3-SCR catalyst

Abstract

CeO₂–WO₃ catalysts were synthesized using the coprecipitation method (CW-C), mixing method (CW-M) and deposition–precipitation method (CW-DP). Among these, the CW-C catalyst exhibits exceptional denitration (deNO_x) performance and N₂ selectivity, achieving over 90% deNO_x efficiency and approximately 100% N₂ selectivity at 220–550 °C with a GHSV of 60 000 h⁻¹. Notably, its catalytic performance at low temperature has surpassed that of other catalysts significantly. This outstanding deNO_x performance can be attributed to the intense mutual effect between CeO₂ and WO₃ and the formation of Ce₂(WO₃)₃ species; a series of characterization studies reveal that CW-C has heightened redox properties and more surface acid sites, as well as the presence of Ce³⁺ species and chemisorption oxygen species (O₂⁻/O⁻). The reaction mechanism over the CW-C catalyst mainly follows the E–R mechanism, while CW-DP and CW-M mainly go through the L–H mechanism at temperatures below 350 °C.