The catalytic performance of Mn/TiWOx catalyst for selective catalytic reduction of NOx with NH3

• The NH3-SCR activities of Mn/TiWOx catalysts are higher than that of Mn/TiO2 catalyst.
• The NH3-SCR reaction over Mn/TiWOx (1:1) followed the Langmuir–Hinshelwood mechanism.
• The adsorbed NH3 species were more active than NOx species in the NH3-SCR reaction.

A series of Mn/TiWOx catalysts were prepared and used in NH3-SCR reaction for NOx emission control. The experimental results showed that the SCR activities of Mn/TiWOx catalysts are higher than that of Mn/TiO2 catalyst. After that, several characterization techniques including XRD, H2-TPR, NH3-TPD, XPS were used to investigate the effect of TiWOx support on the SCR performance of Mn/TiWOx (1:1) catalyst. The stronger reducibility and NH3 adsorption capacity, and more surface chemisorbed oxygen of Mn/TiWOx (1:1) should all contribute to its better SCR performance. Moreover, Mn/TiWOx (1:1) catalyst shows higher N2 selectivity, better SO2 tolerance and stability than Mn/TiO2 catalyst. The results of in situ DRIFT study revealed that the NH3-SCR reactions over Mn/TiO2 and Mn/TiWOx (1:1) were all followed the Langmuir–Hinshelwood mechanism, in which the SCR reaction takes place between the adsorbed NH3 species and NOx species.

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