The behavior of the manganese-cerium loaded metal-organic framework in elemental mercury and NO removal from flue gas

- The MOF was used as Mn-Ce catalyst support for Hg0 and NO removal.
- The MOF support exhibited superiority in O2 utilization and storage.
- The ratio of Mn3+/Mn4+ remain stable and the ratio of Ce3+/Ce4+ decreased during the reaction.

Mn-Ce loaded metal-organic framework (MnCe@MOF) catalyst was obtained by incipient wetness impregnation of MOF with manganese-cerium nitrate. The obtained materials were investigated as potential catalysts for elemental mercury (Hg0) and NO removal from simulate flue gas and the results indicated that MnCe@MOF exhibited superior activity in comparison with the conventional catalysts Mn-Ce loaded ZrO2, especially at low temperatures (<250 °C). It was established that the crystalline structure of MOF support influenced the catalytic behavior in a complex way. The MOF support played an important role in promoting dispersion of active components, improving the Hg0 adsorption and enhancing oxygen utilization, which resulted in a desirable catalytic activity. To understand the mechanism of the Mn-Ce catalyst better, dynamic valence state evolution during the Hg0 oxidation for the active components was investigated. The ratio of Mn3+/Mn4+ remained constant during the reaction at various temperatures, indicating the stability of Mn in the catalytic process. However, the ratio of Ce3+/Ce4+ gradually decreased with extended periods of reaction time, which most likely lead to the decreased of chemical adsorbed oxygen on the catalyst.