Enhancement of Ce1−xSnxO2 support in LaMnO3 for the catalytic oxidation and adsorption of elemental mercury

Abstract

Mn-based perovskite oxide was used as the active site for elemental mercury (Hg⁰) removal from coal-fired flue gas. Ce_1−xSn_xO₂ binary oxides were selected as the catalyst supports for LaMnO₃ to enhance the catalytic oxidation and adsorption performance. Ce_0.7Sn_0.3O₂ had the best Hg⁰ removal performance among the as-prepared Ce_1−xSn_xO₂ binary oxides; the Hg⁰ removal efficiency was 95.2% at 350 °C. LaMnO₃ had better performance at low temperatures (<200 °C). LaMnO₃/Ce_0.7Sn_0.3O₂ enlarged the reaction temperature window and enhanced the Hg⁰ removal efficiencies. The correlation between the physicochemical properties and the catalytic removal performance was investigated by XRD, BET surface area measurements, Raman spectroscopy, H₂-TPR and XPS analysis. With the addition of Ce–Sn binary oxides as catalyst support, the surface areas of LaMnO₃ was enlarged, the reducibility was enhanced and the oxygen mobility was improved. In addition, the Hg⁰ removal mechanism was illustrated on the basis of the experimental results. The roles of Ce, Sn and LaMnO₃ were also discussed in this study.