Novel metal-organic framework supported manganese oxides for the selective catalytic reduction of NOx with NH_3: Promotional role of the support

摘要

A novel MnOx@MIL-125(Ti) catalyst was constructed for the selective catalytic reduction (SCR) of NOx with NH3, in which MIL-125(Ti), a kind of metal-organic frameworks (MOFs), was used as the support because of the structural feature, large surface area and high thermal stability. The SCR results showed that MnOx@MIL-125(Ti) exhibited high deNOx ability and N-2 selectivity in a wide operating temperature range. Moreover, it exhibited better SO2 resistance than MnOx/TiO2 (P25). Characterization results revealed that MIL-125(Ti) had resulted in a high dispersion of MnOx and a strong metal-support interaction for MnOx@MIL-125(Ti), which could promote the formation of the abundant Mn4+ and surface chemical oxygen, facilitating the activation of the reactants. In situ DRIFTS results suggested that NH3-SCR over MnOx@MIL-125(Ti) followed both Langmuir-Hinshelwood (L-H) and Eley-Rideal (E-R) mechanism. In addition, NO- species were proved to be the important intermediates which were involved in SCR reaction.