The role of cerium in the improved SO2 tolerance for NO reduction with NH3 over Mn-Ce/TiO2 catalyst at low temperature

Effect of metal ions doping (M = Ti4+, Sn4+) on the catalytic performance of MnO /CeO2 catalyst for low temperature selective catalytic reduction of NO with NH3

“…We assume that sulfate species might preferentially form on CeTi support and lessening the sulfation of MnOx, which provides a protection of active sites from being poisoned. It was also been report by Wu and co-workers [13] that the addition of dopant to Mn/Ti catalyst might partially prevent surface Mn active sites of sample from being sulfated. So, doping of Ti may be an available way to improve the sulfur resistance of Mn/CeO 2 catalyst.…”

“…CeO 2 was used as a catalyst in NH 3 -SCR and promoter in the three way catalyst (TWC) [12]. Moreover, it has been proved that ceria can enhance the NO x adsorption, provide stronger Brønsted acid sites, enhance the oxidization of NO to NO 2 and improve sulfur resistance, which was beneficial for the NH 3 -SCR reaction [13]. However, pure CeO 2 is not suitable for the practical application because of the small specific surface area and the low thermal stability [14].…”

The Keggin Structure: An Important Factor in Governing NH3–SCR Activity Over the V2O5–MoO3/TiO2 Catalyst

“…However, NH 3 -SCR over these catalysts can only be operated in a narrow temperature window of 300-400 °C, and the phase of TiO 2 can be transformed from anatase to rutile at elevated temperature; this phase transformation results in a loss of SCR activity [3]. Great efforts have been made to improve the low-temperature activity of NH 3 -SCR over catalysts, such as CeO 2 /TiO 2 , MnO x /Al 2 O 3 , CuO-CeO 2 /TiO 2 , and Mn-Ce/TiO 2 , which have been developed and used as SCR catalysts [4][5][6]. The main problem with these catalysts is SO 2 resistance because SO 2 oxidation that occurs with H 2 O results in the formation of ammonium sulfates, which inhibit SCR activity of the catalysts at temperatures below 300 °C [7][8][9][10].…”

Effect of Ce/Y Addition on Low-Temperature SCR Activity and SO2 and H2O Resistance of MnOx/ZrO2/MWCNTs Catalysts

“…Compared to the fresh catalysts, a peak around 1102 cm −1 , assigned to the SO 4 2− species, appeared after reacting with SO 2 [6,45]. From the partial magnification of corresponding FTIR spectra, the peak became weaker after loading Ce or Y, indicating that the addition of Ce or Y may prevent the manganese active sites from being sulfated to some extent [46]. …”