Low-temperature selective catalytic reduction of NOx with NH3 over hierarchically macro-mesoporous Mn/TiO2

• The hierarchically macro-mesoporous Mn/TiO2 catalyst was prepared.
• The catalyst showed excellent low-temperature deNOx activity and SO2-resistance.
• The catalyst provided large specific surface area.
• Manganese oxides were highly dispersed on hierarchically porous titania support.
• Coordinated NH3 and bridging nitrate were the key intermediates in the reaction.

The hierarchically macro-mesoporous Mn/TiO2 catalyst (HM-Mn/TiO2) using Pluronic F127 as pore agent was synthesized by sol–gel method and used for low-temperature selective catalytic reduction of NOx with NH3. Compared with Mn/TiO2, HM-Mn/TiO2 showed higher low-temperature activity and better SO2-resistance. The characterization results indicated that the introduction of pore agent (Pluronic F127) could improve the dispersion of manganese oxides and thus increase the catalyst surface area. The in situ DRIFTS results revealed that more coordinated NH3 and bridging nitrate, which were the key reactants in reaction, could be adsorbed on HM-Mn/TiO2 than those on Mn/TiO2.

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