초록 |
Selective catalytic reduction (SCR) is a well-established technology which controls NOx emission. Recently, Mn based catalysts are widely accepted as efficient catalysts in SCR reaction, and various kinds of materials were used as support. In this study, we focused on hydrous titania with highly porous structure and a large surface area, which is regarded as potential support materials. Mn oxide supported on two different groups of titania, hydrous or crystalline titanium oxide, were investigated for the SCR reaction. Mn supported on hydrous TiO2 catalyst exhibited higher NOx conversion over wide temperature range as well as the suppressed formation of N2O compared to Mn supported on crystalline TiO2. Also, Mn/hydrous TiO2 showed relatively lower performance in ammonia oxidation than Mn/crystalline TiO2 which is regarded as the side reaction. Combined several characterization results indicates that manganese species are more strongly interacted with hydrous TiO2 than crystalline TiO2, resulting in different redox behavior and oxidation state of Mn oxides. It can be concluded that the activity and selectivity of Mn/TiO2 catalysts in NH3 SCR reaction were affected by initial state of titania support. |