Design of MnO2/CeO2-MnO2 hierarchical binary oxides for elemental mercury removal from coal-fired flue gas

MnO2/CeO2-MnO2 hierarchical binary oxide was synthesized for elemental mercury (Hg-0) removal from coal-fired flue gas. CeO2 in-situ grow on the surface of carbon spheres, and that CeO2@CSs acted as precursor for porous MnO2/CeO2-MnO2. XRD, Raman, XPS, FT-IR, and H-2-TPR were selected for the physical structural and chemical surface analysis. The results indicated that the composite has sufficient surface oxygen and hierarchical porous structure. The Hg-0 removal experiments results indicated that MnO2/CeO2-MnO2 exhibited excellent Hg-0 removal performance, with an 89% removal efficiency of total 300 min at 150 degrees C under 4% O-2. MnO2 was the primary active site for Hg-0 catalytic oxidation. The porous structure was beneficial for gaseous mercury physically adsorption. In addition, CeO2 enhanced the oxygen capture performance of the composite and the oxidation performance for MnO2. Moreover, the effects of O-2, SO2 and H2O were also tested in this study. O-2 promoted the Hg-0 removal reaction. While SO2 and H2O can poison the MnO2 active site, resulted in a low Hg-0 removal efficiency. (C) 2017 Elsevier B.V. All rights reserved.