A Sulfur-Tolerant MOF-Based Single-Atom Fe Catalyst for Efficient Oxidation of NO and Hg0.

Catalytic oxidation of NO and Hg0 is a crucial step to eliminate multiple pollutants from emissions from coal-fired power plants. However, traditional catalysts exhibit low catalytic activity and poor sulfur resistance due to low activation ability and poor adsorption selectivity. Herein, a single-atom Fe decorated N-doped carbon catalyst (Fe1 -N4 -C), with abundant Fe1 -N4 sites, based on a Fe-doped metal-organic framework is developed to oxidize NO and Hg0 . The results demonstrate that the Fe1 -N4 -C has ultrahigh catalytic activity for oxidizing NO and Hg0 at low and room temperature. More importantly, Fe1 -N4 -C exhibits robust sulfur resistance as it preferably adsorbs reactants over sulfur oxides, which has never been achieved before with traditional catalysts. Furthermore, SO2 boosts the catalytic oxidation of NO over Fe1 -N4 -C through accelerating the circulation of active sites. Density functional theory calculations reveal that the Fe1 -N4 active sites result in a low energy barrier and high adsorption selectivity, providing detailed molecular-level understanding for its excellent catalytic performance. This is the first report on NO and Hg0 oxidation over single-atom catalysts with strong sulfur tolerance. The outcomes demonstrate that single-atom catalysts are promising candidates for catalytic oxidation of NO and Hg0 enabling cleaner coal-fired power plant operations.

Dielectric Barrier Discharge Coupling Catalytic Oxidation for Highly Efficient Hg0 Conversion.

In this work, we prepared CuCe/Ti catalysts in a dielectric barrier discharge (DBD) reactor and proposed a new method for flue gas mercury oxidation using DBD coupling CuCe/Ti catalyst. Our experiments verified the oxidation efficiency of flue gas Hg0 (ηHg) and clarified the influence of O2 content, NO concentration, SO2 concentration, water vapor content, and discharge voltage on ηHg. The oxidation mechanism of Hg0 in the DBD-CuCe/Ti reactor was also illustrated. The Hg0 oxidation experiment on the simulated flue gas (70 µg/m3 Hg0 + 300 mg/m3 NO + 1000 mg/m3 SO2 + 6%O2) with a flow rate of 1 L/min showed that when the amount of catalyst was 1.25 g and the discharge voltage was 9.5 kV, a ηHg of 93% can be achieved, which indicates that the DBD coupling CuCe/Ti technology is suitable for Hg0 conversion and flue gas mercury removal.