Activity and antitoxic properties of Cr-MnOx/TiO2-ZrO2 for low-temperature selective catalytic reduction of NO
Using a sol-gel prepared TiO2-ZrO2 carrier,Cr-MnOx/TiO2-ZrO2composite catalysts were synthesized by a critic acid solution impregnation method. The physical and chemical properties of the catalysts were characterized by X-ray diffraction,specific surface area determination(BET),scanning electron mic...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | zho |
| Published: |
Science Press
2015-08-01
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| Series: | 工程科学学报 |
| Subjects: | |
| Online Access: | http://cje.ustb.edu.cn/article/doi/10.13374/j.issn2095-9389.2015.08.012 |
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| Summary: | Using a sol-gel prepared TiO2-ZrO2 carrier,Cr-MnOx/TiO2-ZrO2composite catalysts were synthesized by a critic acid solution impregnation method. The physical and chemical properties of the catalysts were characterized by X-ray diffraction,specific surface area determination(BET),scanning electron microscopy and X-ray photoelectron spectroscopy. Meanwhile,the lowtemperature catalytic activity and the sulfur and water resistance were evaluated with selective catalytic reduction(SCR) of NO by NH3. The introduction of Cr element to MnOxyields a new CrMn1.5O4 active phase,in which Mn primarily exists as Mn3+ and Mn4+.The Cr5+ valence state facilitates the transformation of Mn3+ to high oxidation state Mn4+,which is beneficial to the low temperature SCR reaction. Because of lower first ionization energy and electronegativity,Cr preferentially reacts with SO42- and SO32- than Mn,thus protecting MnOx not to be sulphatized and resulting in the enhanced antitoxic performance of Cr-MnOx/TiO2-ZrO2. Among the prepared five catalysts with different molar ratios of Cr/(Cr + Mn),Cr(0.4)-MnOx/TiO2-ZrO2 demonstrates the best performance owing to the largest surface area and the best particle dispersion,and a 95.8% denitrification efficiency can be achieved at 180℃.When 5% H2O and 10-4 SO2 are simultaneously added,the denitrification efficiency decreases slowly and stabilizes at 73% after 8h reaction. |
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| ISSN: | 2095-9389 |