The enhancement of NH-SCR performance for CeO catalyst by CO pretreatment.

CO pretreatment was found to effectively improve the SCR performance of CeO, with over 90% at about 300 °C. The larger specific area and the decrease of CeO crystallization indicated the modification of the surface structure after CO pretreatment. Abundant Ce species and active oxygen, better reducibility, and the higher surface adsorption capacity were mainly responsible for its enhanced SCR performance. DRIFT analysis revealed the presumed coexistence of two reaction routes that the L-H mechanism was related to the reaction temperature, while the reaction rate of E-R route was almost directly proportional to the NO concentration at a certain temperature, based on the kinetic calculation. In addition, the CO-pretreated CeO also exhibited a better poisoning tolerance for SO and HO and excellent thermal stability and circularity. Graphical abstract The process of NH-SCR reaction over CeO-CO catalyst.