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Effects of SO 2 on selective catalytic reduction of NO with NH 3 over a TiO 2 photocatalyst

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ABSTRACT

The effect of SO2 gas was investigated on the activity of the photo-assisted selective catalytic reduction of nitrogen monoxide (NO) with ammonia (NH3) over a TiO2 photocatalyst in the presence of excess oxygen (photo-SCR). The introduction of SO2 (300 ppm) greatly decreased the activity of the photo-SCR at 373 K. The increment of the reaction temperature enhanced the resistance to SO2 gas, and at 553 K the conversion of NO was stable for at least 300 min of the reaction. X-ray diffraction, FTIR spectroscopy, thermogravimetry and differential thermal analysis, x-ray photoelectron spectroscopy (XPS), elemental analysis and N2 adsorption measurement revealed that the ammonium sulfate species were generated after the reaction. There was a strong negative correlation between the deposition amount of the ammonium sulfate species and the specific surface area. Based on the above relationship, we concluded that the deposition of the ammonium sulfate species decreased the specific surface area by plugging the pore structure of the catalyst, and the decrease of the specific surface area resulted in the deactivation of the catalyst.

No MeSH data available.


XRD patterns of the catalysts before and after the reaction. (a) BR, (b) AR-373K, (c) AR-433K and (d) AR-533K. Patterns are offset for clarity.
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Figure 2: XRD patterns of the catalysts before and after the reaction. (a) BR, (b) AR-373K, (c) AR-433K and (d) AR-533K. Patterns are offset for clarity.

Mentions: The XRD patterns of the catalysts are shown in figure 2. In all the catalysts, only the diffraction pattern of anatase TiO2 was observed. Crystalline sizes of anatase TiO2 were estimated by the Scherrer equation using the diffraction peaks of (101), and the results are listed in table 1. The crystalline size did not change (about 15 nm) after the reaction, revealing that the aggregation of TiO2 particles did not occur under the reaction conditions at all the reaction temperatures.


Effects of SO 2 on selective catalytic reduction of NO with NH 3 over a TiO 2 photocatalyst
XRD patterns of the catalysts before and after the reaction. (a) BR, (b) AR-373K, (c) AR-433K and (d) AR-533K. Patterns are offset for clarity.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC5036466&req=5

Figure 2: XRD patterns of the catalysts before and after the reaction. (a) BR, (b) AR-373K, (c) AR-433K and (d) AR-533K. Patterns are offset for clarity.
Mentions: The XRD patterns of the catalysts are shown in figure 2. In all the catalysts, only the diffraction pattern of anatase TiO2 was observed. Crystalline sizes of anatase TiO2 were estimated by the Scherrer equation using the diffraction peaks of (101), and the results are listed in table 1. The crystalline size did not change (about 15 nm) after the reaction, revealing that the aggregation of TiO2 particles did not occur under the reaction conditions at all the reaction temperatures.

View Article: PubMed Central - PubMed

ABSTRACT

The effect of SO2 gas was investigated on the activity of the photo-assisted selective catalytic reduction of nitrogen monoxide (NO) with ammonia (NH3) over a TiO2 photocatalyst in the presence of excess oxygen (photo-SCR). The introduction of SO2 (300 ppm) greatly decreased the activity of the photo-SCR at 373 K. The increment of the reaction temperature enhanced the resistance to SO2 gas, and at 553 K the conversion of NO was stable for at least 300 min of the reaction. X-ray diffraction, FTIR spectroscopy, thermogravimetry and differential thermal analysis, x-ray photoelectron spectroscopy (XPS), elemental analysis and N2 adsorption measurement revealed that the ammonium sulfate species were generated after the reaction. There was a strong negative correlation between the deposition amount of the ammonium sulfate species and the specific surface area. Based on the above relationship, we concluded that the deposition of the ammonium sulfate species decreased the specific surface area by plugging the pore structure of the catalyst, and the decrease of the specific surface area resulted in the deactivation of the catalyst.

No MeSH data available.