V2O5/WO3‐TiO2 and V2O5/WO3‐TiO2‐SiO2 catalysts were prepared by a wetness impregnation method, and both the catalysts were hydrothermally aged at 750℃ in 10 vol%H2O/air for 24 h. The catalysts were evaluated for N...V2O5/WO3‐TiO2 and V2O5/WO3‐TiO2‐SiO2 catalysts were prepared by a wetness impregnation method, and both the catalysts were hydrothermally aged at 750℃ in 10 vol%H2O/air for 24 h. The catalysts were evaluated for NOx conversion using NH3 as the reductant. Hydrothermal ageing decreased the NOx conversion of V2O5/WO3‐TiO2 catalyst severely over the entire measured tem‐perature range. Interestingly, the NH3‐SCR activity of the silica‐modified catalyst at 220–480℃ is enhanced after ageing. The catalysts were characterized by X‐ray diffraction, nitrogen adsorption, X‐ray fluorescence, Raman spectroscopy, H2 temperature‐programmed reduction, and NH3 temper‐ature‐programmed desorption. The addition of silica inhibited the phase transition from anatase to rutile titania, growth of TiO2 crystallite size and shrinkage of catalyst surface area. Consequently, the vanadia species remained highly dispersed and the hydrothermal stability of the V2O5/WO3‐TiO2 catalyst was significantly improved.展开更多
The selective catalytic reduction of NOV with NH3 (NH3-SCR) is a very effective technology to control the emission of NOA, and the thermal stability of NH3-SCR catalyst is very important for removal of NOV from diesel...The selective catalytic reduction of NOV with NH3 (NH3-SCR) is a very effective technology to control the emission of NOA, and the thermal stability of NH3-SCR catalyst is very important for removal of NOV from diesel engines. In this work, V2O5/WO3-TiO2 (VWT) and SiO2- doped V2O5/WO3-TiO2 (VWTSi10)) catalysts were prepared by impregnation method and characterized by Brunauer- Emmett-Teller (BET), X-ray diffraction (XRD), Raman, temperature programmed reduction by hydrogen (H2-TPR), X-ray photoelectron spectroscopy (XPS) and temperature programmed desorption by ammonia (NH3- TPD). The doping of SiO2 promotes the thermal stability of V2O5/WO3-TiO? for NH3-SCR significantly. After calcination at 650 °C for 50 h, the operation window of 10% SiO2-doped V2O5/WO3-TiO2 is 220-480 °C, while the maximum NOV conversion on V2O5/WO3-TiO2 is about 77%. The presenee of SiO2 obviously blocks the transformation of TiO2 from anatase to rutile and stabilizes the dispersion of VOv and WO3 on the surface. It is available for the existence of V44 and the amount of surface acid sites increases, which inhabits the NH3 oxidation at the high temperature range and promotes NH3-SCR activity.展开更多
Mesoporous superacids S2O82–-Fe2O3/SBA-15(SFS)with active nanoparticles are prepared by ultrasonic adsorption method.This method is adopted to ensure a homo-dispersed nanoparticle active phase,large specific surface ...Mesoporous superacids S2O82–-Fe2O3/SBA-15(SFS)with active nanoparticles are prepared by ultrasonic adsorption method.This method is adopted to ensure a homo-dispersed nanoparticle active phase,large specific surface area and many acidic sites.Compared with bulk S2O82–-Fe2O3,Br?nsted acid catalysts and other reported catalysts,SFS with an Fe2O3 loading of 30%(SFS-30)exhibits an outstanding activity in the probe reaction of alcoholysis of styrene oxide by methanol with 100%yield.Moreover,SFS-30 also shows a more excellent catalytic performance than bulk S2O82–-Fe2O3 towards the alcoholysis of other ROHs(R=C2H5-C4H9).Lewis and Bronsted acid sites on the SFS-30 surfaces are confirmed by pyridine adsorbed infrared spectra.The highly efficient catalytic activity of SFS-30 may be attributed to the synergistic effect from the nano-effect of S2O82–-Fe2O3 nanoparticles and the mesostructure of SBA-15.Finally,SFS-30 shows a good catalytic reusability,providing an 84.1%yield after seven catalytic cycles.展开更多
溶胶-凝胶和浸渍相结合的方法制备锰掺杂WO3-TiO2复合光催化剂,RXD表征,考察WO3和Mn2+掺入量、焙烧温度、焙烧时间及催化剂用量对光催化降解甲基橙的影响。结果表明,500℃焙烧2 h,掺杂量n(Mn2+)∶n(WO3)∶n(TiO2)=0.8∶1∶100时,光催化...溶胶-凝胶和浸渍相结合的方法制备锰掺杂WO3-TiO2复合光催化剂,RXD表征,考察WO3和Mn2+掺入量、焙烧温度、焙烧时间及催化剂用量对光催化降解甲基橙的影响。结果表明,500℃焙烧2 h,掺杂量n(Mn2+)∶n(WO3)∶n(TiO2)=0.8∶1∶100时,光催化活性最高,光催化降解甲基橙溶液,120 m in后,降解率达90%,比单纯TiO2的光催化活性提高81%。展开更多
基金supported by the National Natural Science Foundation of China (51372137)the National High Technology Research and Development Program of China (863 Program,2015AA034603)~~
摘要V2O5/WO3‐TiO2 and V2O5/WO3‐TiO2‐SiO2 catalysts were prepared by a wetness impregnation method, and both the catalysts were hydrothermally aged at 750℃ in 10 vol%H2O/air for 24 h. The catalysts were evaluated for NOx conversion using NH3 as the reductant. Hydrothermal ageing decreased the NOx conversion of V2O5/WO3‐TiO2 catalyst severely over the entire measured tem‐perature range. Interestingly, the NH3‐SCR activity of the silica‐modified catalyst at 220–480℃ is enhanced after ageing. The catalysts were characterized by X‐ray diffraction, nitrogen adsorption, X‐ray fluorescence, Raman spectroscopy, H2 temperature‐programmed reduction, and NH3 temper‐ature‐programmed desorption. The addition of silica inhibited the phase transition from anatase to rutile titania, growth of TiO2 crystallite size and shrinkage of catalyst surface area. Consequently, the vanadia species remained highly dispersed and the hydrothermal stability of the V2O5/WO3‐TiO2 catalyst was significantly improved.
基金financially supported by the National Key Research and Development Program of China (No. 2016YFC0204300)the National High Technology Research and Development Program of China (No. 2015AA034603)+2 种基金the National Natural Science Foundation of China (Nos. 21333003 and 21571061)the "Shu Guang" Project of the Shanghai Municipal Education Commission (No. 12SG29)the Commission of Science and Technology of Shanghai Municipality (No. 15DZ1205305)
摘要The selective catalytic reduction of NOV with NH3 (NH3-SCR) is a very effective technology to control the emission of NOA, and the thermal stability of NH3-SCR catalyst is very important for removal of NOV from diesel engines. In this work, V2O5/WO3-TiO2 (VWT) and SiO2- doped V2O5/WO3-TiO2 (VWTSi10)) catalysts were prepared by impregnation method and characterized by Brunauer- Emmett-Teller (BET), X-ray diffraction (XRD), Raman, temperature programmed reduction by hydrogen (H2-TPR), X-ray photoelectron spectroscopy (XPS) and temperature programmed desorption by ammonia (NH3- TPD). The doping of SiO2 promotes the thermal stability of V2O5/WO3-TiO? for NH3-SCR significantly. After calcination at 650 °C for 50 h, the operation window of 10% SiO2-doped V2O5/WO3-TiO2 is 220-480 °C, while the maximum NOV conversion on V2O5/WO3-TiO2 is about 77%. The presenee of SiO2 obviously blocks the transformation of TiO2 from anatase to rutile and stabilizes the dispersion of VOv and WO3 on the surface. It is available for the existence of V44 and the amount of surface acid sites increases, which inhabits the NH3 oxidation at the high temperature range and promotes NH3-SCR activity.
摘要Mesoporous superacids S2O82–-Fe2O3/SBA-15(SFS)with active nanoparticles are prepared by ultrasonic adsorption method.This method is adopted to ensure a homo-dispersed nanoparticle active phase,large specific surface area and many acidic sites.Compared with bulk S2O82–-Fe2O3,Br?nsted acid catalysts and other reported catalysts,SFS with an Fe2O3 loading of 30%(SFS-30)exhibits an outstanding activity in the probe reaction of alcoholysis of styrene oxide by methanol with 100%yield.Moreover,SFS-30 also shows a more excellent catalytic performance than bulk S2O82–-Fe2O3 towards the alcoholysis of other ROHs(R=C2H5-C4H9).Lewis and Bronsted acid sites on the SFS-30 surfaces are confirmed by pyridine adsorbed infrared spectra.The highly efficient catalytic activity of SFS-30 may be attributed to the synergistic effect from the nano-effect of S2O82–-Fe2O3 nanoparticles and the mesostructure of SBA-15.Finally,SFS-30 shows a good catalytic reusability,providing an 84.1%yield after seven catalytic cycles.
摘要溶胶-凝胶和浸渍相结合的方法制备锰掺杂WO3-TiO2复合光催化剂,RXD表征,考察WO3和Mn2+掺入量、焙烧温度、焙烧时间及催化剂用量对光催化降解甲基橙的影响。结果表明,500℃焙烧2 h,掺杂量n(Mn2+)∶n(WO3)∶n(TiO2)=0.8∶1∶100时,光催化活性最高,光催化降解甲基橙溶液,120 m in后,降解率达90%,比单纯TiO2的光催化活性提高81%。