Simultaneous removal of NO and Hg⁰ using Fe and Co co-doped Mn-Ce/TiO₂ catalysts

Fe and Co co-doped Mn-Ce/TiO₂ (MCT) catalysts were investigated for the simultaneous removal of nitric oxide (NO) and elemental mercury (Hg⁰) at reaction temperature lower than 200 °C. The catalysts were characterized by Brunauer–Emmett–Teller (BET), temperature program reduction (TPR), scanning electron microscope (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analysis. The experimental results showed that the co-doped 2Fe4Co-MCT catalyst exhibited better performance for the simultaneous removal of NO and Hg⁰ compared to Fe or Co doped catalysts. This could be due to higher BET surface area and better redox property of 2Fe4Co-MCT catalyst. In addition, we propose that chemisorbed O₂ played a dominant role in selective catalytic reduction (SCR) of NO while lattice O₂ played a key role in Hg⁰ oxidation. The results also indicate that the introduction of Fe species enhanced the activity of SCR, whereas the introduction of Co species enhanced the oxidation of Hg⁰. The synergistic effect of Fe and Co species in the 2Fe4Co-MCT catalyst are also suggested to be an important mechanism for simultaneously removing NO and Hg⁰.