The effects of manganese precursors on NO catalytic removal with MnO/SiO catalyst at low temperature

The low-temperature catalytic NO removal efficiencies of catalysts with two different manganese precursors, manganese acetate (αMA catalyst) and manganese nitrate (αMN catalyst), were compared and studied. The NH-SCR of NO tests using these catalysts were carried out in a self-made reaction device to measure the catalytic activity of the catalysts. Moreover, the reaction pathway analysis of NH-SCR of NO on the surface of MnO/SiO catalyst and MnO/SiO catalyst were performed based on DFT calculations individually. The experimental results show that the NO conversion of αMN catalyst is higher than the αMA catalyst at low temperature (< 180 °C). Besides, the XRD test shows that the main crystal phase is MnO for αMN catalysts, and MnO for αMA catalyst, and the XPS characterization exhibits that the αMN catalyst has the highest MnO/MnO ratio. Moreover, DFT calculations indicate that the decompositions of NHNO and NHNO are the rate determining steps in the whole NH-SCR of NO process and the decomposition activation energy of NHOH and NHNO on MnO is lower than that on MnO. This is the main reason for the higher NO conversion of catalyst prepared with manganese nitrate as precursor at low temperature.