Enhanced low-temperature NH 3 -SCR performance of MnO x /CeO 2 catalysts by optimal solvent effect

Abstract A series of MnO x /CeO 2 catalysts were prepared by modulating the solvents (deionized water (DW), anhydrous ethanol (AE), acetic acid (AA), and oxalic acid (OA) solution) with the purpose of improving the low-temperature NH 3 -SCR performance, broadening the operating temperature window, and enhancing the H 2 O + SO 2 resistance. The synthesized catalysts were characterized by means of N 2 -physisorption, XRD, EDS mapping, Raman, XPS, H 2 -TPR, NH 3 -TPD, and in situ DRIFTS technologies. Furthermore, the catalytic performance and H 2 O + SO 2 resistance were evaluated by NH 3 -SCR model reaction. The obtained results indicate that MnO x /CeO 2 catalyst prepared with oxalic acid solution as a solvent exhibits the best catalytic performance among these catalysts, which shows above 80% NO conversion during a wide operating temperature range of 100–250 °C and good H 2 O + SO 2 resistance for low-temperature NH 3 -SCR reaction. This is related to that oxalic acid solution can promote the dispersion of MnO x and enhance the electron interaction between MnO x and CeO 2 , which are beneficial to improving the physicochemical property of MnO x /CeO 2 catalyst, and further lead to the enhancement of catalytic performance and good H 2 O + SO 2 resistance.