High catalytic activity of Mn-based catalyst in NO oxidation at low temperature and over a wide temperature span

In-Situ DRIFTS for Reaction Mechanism and SO2 Poisoning Mechanism of NO Oxidation Over γ-MnO2 with Good Low-Temperature Activity

“…During the NO oxidation process, the hydroxyl groups are involved in the reaction of NO oxidation, but their consumptions are irreversible, implying that the H-bond can't be recovered. In our previous study [21], it was found that no noticeable decrease in NO conversion over γ-MnO 2 is observed in the continuous oxidation reaction lasting for 66 h, and there is no H 2 O in this stability test process, further implying that hydroxyl groups are not the main factors influencing the catalytic performance. Moreover, it has been reported that the catalytic activity of γ-MnO 2 is in close correlation to the concentration of the surface chemisorbed oxygen [16,17,21], implying that the surface chemisorbed oxygen is very important for NO oxidation.…”

“…All the chemicals used as received without further purification were of analytical grade, and deionized water was employed to prepare the solutions used in the study. The preparation process of γ-MnO 2 by the precipitation method can be found in our previous study [21]. Specifically, 2.8475 g of KMnO 4 and 0.5 mL of concentrated HNO 3 were dissolved in 200 mL of deionized water to obtain solution (I).…”

“…It has also been accepted that the catalytic activity of γ-MnO 2 is in close correlation to the concentration of the surface chemisorbed oxygen [16,17,21]. Therefore, the transient responses experiment was carried out at 220 °C with a GHSV of 48,000 mL g −1 h −1 to evaluate the effect of O 2 on the NO oxidation over the γ-MnO 2 catalyst, and the results are shown in the Fig.…”

“…More than that, it has been reported that the surfactant polyethylene glycol (PEG) involved in preparation and modification of catalysts can improve the catalysts' surface areas and catalytic activities [19,20]. Thus, γ-MnO 2 modified with PEG was synthesized by precipitation to further improve its low-temperature activity, and results indicate PEG does improve the low-temperature activity of γ-MnO 2 due to the increment of catalyst's surface area and the enhanced adsorption for NO and O 2 at low temperature [21]. In the present study, this modified γ-MnO 2 was chosen to investigate the mechanism of NO oxidation at low temperature via a systematic in-situ DRIFTS experiments.…”

Co-precipitation Synthesized MnOx-CeO2 Mixed Oxides for NO Oxidation and Enhanced Resistance to Low Concentration of SO2 by Metal Addition

“…Power plants, industrial boilers, and motor vehicle engine discharge NO x via fossil fuels combustion inevitably [2]. After complex atmospheric chemical reactions, exhausted NO x will be converted to the culprit of many typical environmental events, such as photochemical smog, ozone depletion, acid rain, and green-house effect [3][4][5]. Conventionally, the three-layer SCR (selective catalytic reduction) catalyst, assembled in coal-fired power plants, could satisfy the ultra-low emission standard in China (i.e., NO x < 50 mg•Nm −3 ) [6].…”