Enhancement in the Hg⁰ oxidation efficiency and sulfur resistance of CuCl₂-modified MnO_x-CeO_x nanorod catalysts

In this study, a series of CuCl₂-modified MnO_x-CeO_x nanorods were synthesized for the oxidation of Hg⁰. The addition of CuCl₂ resulted in an enhancement in the catalyst’s Hg⁰ oxidation ability, and Hg⁰ oxidation efficiency reached >97% from 150 to 250 °C. In the MnO_x-CeO_x catalysts, Mn⁴⁺ played the role of the active species for Hg⁰ oxidization, but in the CuCl₂-doped catalysts Cl⁻ also contributed to Hg⁰ oxidation, conferring the superior performance of these samples. The introduction of SO₂ led to a decrease in the availability of Mn⁴⁺, and the Hg⁰ oxidation efficiency of MnO_x-CeO_x decreased from about 100% to about 78%. By contrast, CuCl₂-promoted samples maintained a Hg⁰ oxidation efficiency of about 100% during the SO₂ deactivation cycle due to the high reactivity of Cl⁻.