The deposition of NH4 HSO4 and the poisoning effect of SO2 on SCR catalyst are the main obstacles that restrict the industrial application of CeO2-doped SCR catalysts.In this work,deposited NH4 HSO4 decomposition beha...The deposition of NH4 HSO4 and the poisoning effect of SO2 on SCR catalyst are the main obstacles that restrict the industrial application of CeO2-doped SCR catalysts.In this work,deposited NH4 HSO4 decomposition behavior and SO2 poisoning over V2 O5-MoO3/TiO2 catalysts modified with CeO2 and SiO2 were investigated.By the means of characterization analysis,it was found that the addition of SiO2 into VMo/Ti-Ce had an impact on the interaction existed between catalyst surface atoms and NH4 HSO4.Temperatureprogrammed methods and in situ diffused reflectance infrared Fourier transform spectroscopy(DRIFTS)experiments indicated that the doping of SiO2 promoted the decomposition of deposited NH4 HSO4 on VMo/Ti-Ce catalyst surface by reducing the thermal stability of NH4 HSO4 and enhancing the NH4 HSO4 reactivity with NO in low temperature.And this improvement may be the reason for the better catalytic activity than VMo/Ti-Ce in the case of NH4 HSO4 deposition.Accompanied with cerium sulfate species generated over catalyst surface,the conversion of SO2 to SO3 was inhibited in SiCe mixed catalyst.The addition of SiO2 could promote the decomposition of cerium sulfate,which may be a potential strategy to enhance the resistance of SO2 poisoning over CeO2-modifed catalysts.展开更多
The effect of molybdenum oxide on the activity and durability of Ce O2-Ti O2 catalyst for NO reduction by NH3 was examined. It was found that the introduction of Mo could improve the low-temperature NH3-SCR activity a...The effect of molybdenum oxide on the activity and durability of Ce O2-Ti O2 catalyst for NO reduction by NH3 was examined. It was found that the introduction of Mo could improve the low-temperature NH3-SCR activity and SO2/H2 O durability of the Ce O2-Ti O2 catalyst and an optimal loading of Mo was 4?wt.%. The best Mo O3/Ce O2-Ti O2 catalyst displayed over 90% NO conversion from 200 °C to 400 °C and obtained 4-fold increase in NO conversion compared to Ce O2-Ti O2 at 150 °C. The characterization results revealed that the number of Br?nsted acid sites over Mo O3/Ce O2-Ti O2 was significantly increased, and the adsorption of nitrate species was dramatically weakened because of the coverage of Mo O3, which were favorable for the high NH3-SCR performance. It is believed that the Mo O3/Ce O2-Ti O2 catalyst is a suitable substitute for the NH3-SCR reaction.展开更多
Quantum chemical calculation was carried out to choose a promoter which can reduce the poisoning of V2O5/TiO2 catalysts by SO2. Several atoms were chosen as candidates and new catalysts were synthesized by impregnatio...Quantum chemical calculation was carried out to choose a promoter which can reduce the poisoning of V2O5/TiO2 catalysts by SO2. Several atoms were chosen as candidates and new catalysts were synthesized by impregnation method. The NOx conversion rate was measured at temperatures between 100 and 400 ℃ and poisoning effect was investigated. The most promising candidate promoter, Se, was excluded because of its high vapor pressure. On the other hand, Sb shows best promoting properties. Sb promoted catalyst reaches the maximum NOx conversion rate at 250 ℃. It also shows considerably enhanced resistance to poisoning of V2O5/TiO2 catalysts by SO2.展开更多
基金supported by the National Natural Science Foundation of China(No.51576039)
文摘The deposition of NH4 HSO4 and the poisoning effect of SO2 on SCR catalyst are the main obstacles that restrict the industrial application of CeO2-doped SCR catalysts.In this work,deposited NH4 HSO4 decomposition behavior and SO2 poisoning over V2 O5-MoO3/TiO2 catalysts modified with CeO2 and SiO2 were investigated.By the means of characterization analysis,it was found that the addition of SiO2 into VMo/Ti-Ce had an impact on the interaction existed between catalyst surface atoms and NH4 HSO4.Temperatureprogrammed methods and in situ diffused reflectance infrared Fourier transform spectroscopy(DRIFTS)experiments indicated that the doping of SiO2 promoted the decomposition of deposited NH4 HSO4 on VMo/Ti-Ce catalyst surface by reducing the thermal stability of NH4 HSO4 and enhancing the NH4 HSO4 reactivity with NO in low temperature.And this improvement may be the reason for the better catalytic activity than VMo/Ti-Ce in the case of NH4 HSO4 deposition.Accompanied with cerium sulfate species generated over catalyst surface,the conversion of SO2 to SO3 was inhibited in SiCe mixed catalyst.The addition of SiO2 could promote the decomposition of cerium sulfate,which may be a potential strategy to enhance the resistance of SO2 poisoning over CeO2-modifed catalysts.
基金supported by the National Natural Science Foundation of China(21773106,21707066,21677069,and 21806077)the China Postdoctoral Science Foundation(2018M642206)~~
文摘The effect of molybdenum oxide on the activity and durability of Ce O2-Ti O2 catalyst for NO reduction by NH3 was examined. It was found that the introduction of Mo could improve the low-temperature NH3-SCR activity and SO2/H2 O durability of the Ce O2-Ti O2 catalyst and an optimal loading of Mo was 4?wt.%. The best Mo O3/Ce O2-Ti O2 catalyst displayed over 90% NO conversion from 200 °C to 400 °C and obtained 4-fold increase in NO conversion compared to Ce O2-Ti O2 at 150 °C. The characterization results revealed that the number of Br?nsted acid sites over Mo O3/Ce O2-Ti O2 was significantly increased, and the adsorption of nitrate species was dramatically weakened because of the coverage of Mo O3, which were favorable for the high NH3-SCR performance. It is believed that the Mo O3/Ce O2-Ti O2 catalyst is a suitable substitute for the NH3-SCR reaction.
基金This research was supportedby a grant fromKorea Institute of Science and Technology(2E19500).
文摘Quantum chemical calculation was carried out to choose a promoter which can reduce the poisoning of V2O5/TiO2 catalysts by SO2. Several atoms were chosen as candidates and new catalysts were synthesized by impregnation method. The NOx conversion rate was measured at temperatures between 100 and 400 ℃ and poisoning effect was investigated. The most promising candidate promoter, Se, was excluded because of its high vapor pressure. On the other hand, Sb shows best promoting properties. Sb promoted catalyst reaches the maximum NOx conversion rate at 250 ℃. It also shows considerably enhanced resistance to poisoning of V2O5/TiO2 catalysts by SO2.
