A novel catalyst for low temperature selective catalytic reduction (SCR) using CO as reductant, MnO x supported on titania, has been shown to be effective for both elemental mercury capture and low temperature SCR. In low temperature (200 °C) SCR trials using an industrially relevant space velocity (50 000 h−1) and oxygen concentration (2 vol %), nearly quantitative reduction of NO x was obtained using CO as the reductant. Fresh catalyst used as an adsorbent for elemental mercury from an inert atmosphere showed remarkable mercury capture capacity, as high as 17.4 mg/g at 200 °C. The catalyst effectively captured elemental mercury after use in NO x reduction. Mercury capture efficiency was not affected by the presence of water vapor. Mercury capacity was reduced in the presence of SO2. Manganese loading and bed temperature, which influence surface oxide composition, were found to be important factors for mercury capture. X-ray photoelectron spectroscopy (XPS) results reveal that the mercury is present in its oxidized form (HgO) in spent catalyst, indicating the participation of lattice oxygen of the catalyst in the reaction. These results suggest that a single-step process integrating low temperature SCR and mercury capture from flue gas might be feasible.

High surface area ceria-titania materials were used as supports for manganese oxide for both warm-gas mercury capture and low temperature selective catalytic reduction. These materials exhibited excellent mercury capture capability at 175 °C. Increasing manganese loadings improves the mercury capacities. In the presence of SO2, only a small decrease in mercury capacity was observed for the CeO2–TiO2 adsorbents. CeO2–TiO2 adsorbents similarly showed excellent stability in the presence of CO and NO. It was also found that the CeO2–TiO2 support can capture Hg0 and Hg2+ simultaneously from nitrogen at 175 °C; the total mercury capacities were high. Brunauer–Emmentt–Teller surface area measurements suggested that increasing manganese loading reduced the surface area due to pore blockage. X-ray diffraction measurements showed that MnOx is in an amorphous state on CeO2–TiO2 materials. X-ray photoelectron spectroscopy (XPS) results indicate that the adsorbed mercury is present as both Hg0 and Hg2+ on these ceria-based materials. The XPS observations also suggest that the incorporation of titanium into the cubic lattice of ceria leads to the formation of more lattice oxygen atoms, leading to greater formation of Hg2+ on the CeO2–TiO2 support.

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Volatile organic compounds (VOCs) include saturated, unsaturated, and other substituted hydrocarbons. VOCs play an important role in the chemistry of the atmosphere by influencing ozone and hydroxyl radical (OH) concentrations, and the conversion rates of nitrogen oxides (NOx). Elevated levels of VOCs and NOx have led to an approximate doubling of ozone in the lower troposphere over the past couple of centuries, making tropospheric ozone the third most important anthropogenic greenhouse gas after carbon dioxide (CO2) and methane. Because of ozone's strong oxidizing properties, increases in tropospheric ozone are a concern for living systems on Earth. Ozone stresses and damages vegetation, resulting in a reduction of terrestrial CO2 sequestration. VOCs also serve as a source of atmospheric secondary organic aerosol (SOA), which influences the solar radiation budget and cloud droplet nucleation. Through these complex interactions, VOCs play an important role in air quality and climate.

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