Manganese doped CeO2–WO3 catalysts for the selective catalytic reduction of NOx with NH3: An experimental and theoretical study

The CeO2–WO3 (CeW) and Mn-doped CeO2–WO3 (MnCeW) catalysts were prepared by co-precipitation method. The MnCeW catalyst exhibited more activity for NOx conversion than the CeW catalyst did below 200 °C. The experiment results showed that the MnCeW catalyst provided more Brønsted acid sites and higher reducibility than the CeW catalyst. Theoretical studies showed that oxygen vacancies can easily form on the MnCeW (110) surface, resulting in more facile NH3 adsorption and higher activity. The reaction mechanism mainly followed the L–H mechanism at 150 °C over the MnCeW catalyst: both adsorbed NH3 and NH4+ react with nitrite species.

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► MnCeW catalyst can yield more NOx conversion than CeW below 200 °C.
► MnCeW catalyst can enhance more NH3 adsorbed on Brønsted acid sites by DRIFTS study. H2-TPR shows that the reducibility of MnCeW is higher than CeW.
► DFT calculated results shows that doping with Mn could lead surface charge redistribution and easily forming oxygen vacancies.
► Reaction routes at 150 °C are also involved and presented that both adsorbed NH3 and NH4+ may react with nitrite species.