This study was aimed to investigate the effects of hydrothermal aging, propene and SO<sub>2</sub> poisoning on the ammonia-selective catalytic reduction (NH<sub>3</sub>-SCR) performance of both...This study was aimed to investigate the effects of hydrothermal aging, propene and SO<sub>2</sub> poisoning on the ammonia-selective catalytic reduction (NH<sub>3</sub>-SCR) performance of both Cu-SAPO-34 and Cu-ZSM-5. The catalytic activities of fresh, aged and poisoned samples were tested in ammonia-selective catalytic reduction (NH<sub>3</sub>-SCR) of NO<sub>x</sub> conditions. The XRD, TG and N<sub>2</sub>-desorption results showed that the structures of the Cu-SAPO-34 and Cu-ZSM-5 remained intact after 750˚C hydrothermally aged, SO<sub>2</sub> and propene poisoned. After hydrothermal aging at 750˚C for 12 h, the NO reduction performance of Cu-ZSM-5 was significantly reduced at lower temperatures, while that of Cu-SAPO-34 was less affected. Moreover, Cu-SAPO-34 catalyst showed high NO conversion with SO<sub>2</sub> or propene compared to Cu-ZSM-5. However, Cu-ZSM-5 showed a larger drop in catalytic activity with SO<sub>2</sub> or propene compared to Cu-SAPO-34 catalyst. The H<sub>2</sub>-TPR results showed that Cu<sup>2 </sup> ions could be reduced to Cu<sup> </sup> and Cu<sup>0</sup> for Cu-ZSM-5, while no significant transformation of copper species was observed for Cu-SAPO-34. Meanwhile, the UV-vis DRS results showed that CuO species were formed in Cu-ZSM-5, while little changes were observed for the Cu-SAPO-34. Cu-SAPO-34 showed high sulfur and hydrocarbon poison resistance compared to Cu-ZSM-5. In summary, Cu-SAPO-34 with small-pore zeolite showed higher hydrothermal stability and better hydrocarbon and sulfur poison resistant than Cu-ZSM-5 with medium-pore.展开更多
Chengdu Branch,Chinese Science Academy,Chengdu610041)abstract:[Mn(ECZ)abstract: 3 ](NO 3 )abstract: 2 is newly prepared by the aqueous solutions of Mn(NO 3 )abstract: 2 and ethyl carbazate(ECZ)abstract:.The crystal st...Chengdu Branch,Chinese Science Academy,Chengdu610041)abstract:[Mn(ECZ)abstract: 3 ](NO 3 )abstract: 2 is newly prepared by the aqueous solutions of Mn(NO 3 )abstract: 2 and ethyl carbazate(ECZ)abstract:.The crystal structure has been determined by X-ray crystal diffraction analysis.It belongs to monoclinic with space group of P2 1 /n.The crystal parameters are:a=1.3974(2)abstract:nm,b=0.8796(2)abstract:nm,c=3.4322(7)abstract:nm,β=9 1.25(1)abstract:°,V=4.2175(1)abstract:nm 3 ,Z=8.Its molecular weight is491.30.Mn 2+ is located on the center of the molecular structure.Ethyl carbazate serves a s a bidentate ligand which coordinates to the metal cations with its carbonyl ox ygen atom and the terminal hydrazine nitrogen atom,forming five-member chelatin g rings,and three such rings are formed in each molecule.The coordination number of the metal ion is six and the coordination configuration of the cen-tral ion is octahedral.Specially,antimer configuration phenomenon is found in the molecu le.The complex is fur-ther characterized by element analysis and IR measurement s.The thermal decomposition mechanism is studied by using TG-DTG and DSC techni ques.CCDC:215675.展开更多
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
文摘This study was aimed to investigate the effects of hydrothermal aging, propene and SO<sub>2</sub> poisoning on the ammonia-selective catalytic reduction (NH<sub>3</sub>-SCR) performance of both Cu-SAPO-34 and Cu-ZSM-5. The catalytic activities of fresh, aged and poisoned samples were tested in ammonia-selective catalytic reduction (NH<sub>3</sub>-SCR) of NO<sub>x</sub> conditions. The XRD, TG and N<sub>2</sub>-desorption results showed that the structures of the Cu-SAPO-34 and Cu-ZSM-5 remained intact after 750˚C hydrothermally aged, SO<sub>2</sub> and propene poisoned. After hydrothermal aging at 750˚C for 12 h, the NO reduction performance of Cu-ZSM-5 was significantly reduced at lower temperatures, while that of Cu-SAPO-34 was less affected. Moreover, Cu-SAPO-34 catalyst showed high NO conversion with SO<sub>2</sub> or propene compared to Cu-ZSM-5. However, Cu-ZSM-5 showed a larger drop in catalytic activity with SO<sub>2</sub> or propene compared to Cu-SAPO-34 catalyst. The H<sub>2</sub>-TPR results showed that Cu<sup>2 </sup> ions could be reduced to Cu<sup> </sup> and Cu<sup>0</sup> for Cu-ZSM-5, while no significant transformation of copper species was observed for Cu-SAPO-34. Meanwhile, the UV-vis DRS results showed that CuO species were formed in Cu-ZSM-5, while little changes were observed for the Cu-SAPO-34. Cu-SAPO-34 showed high sulfur and hydrocarbon poison resistance compared to Cu-ZSM-5. In summary, Cu-SAPO-34 with small-pore zeolite showed higher hydrothermal stability and better hydrocarbon and sulfur poison resistant than Cu-ZSM-5 with medium-pore.
文摘Chengdu Branch,Chinese Science Academy,Chengdu610041)abstract:[Mn(ECZ)abstract: 3 ](NO 3 )abstract: 2 is newly prepared by the aqueous solutions of Mn(NO 3 )abstract: 2 and ethyl carbazate(ECZ)abstract:.The crystal structure has been determined by X-ray crystal diffraction analysis.It belongs to monoclinic with space group of P2 1 /n.The crystal parameters are:a=1.3974(2)abstract:nm,b=0.8796(2)abstract:nm,c=3.4322(7)abstract:nm,β=9 1.25(1)abstract:°,V=4.2175(1)abstract:nm 3 ,Z=8.Its molecular weight is491.30.Mn 2+ is located on the center of the molecular structure.Ethyl carbazate serves a s a bidentate ligand which coordinates to the metal cations with its carbonyl ox ygen atom and the terminal hydrazine nitrogen atom,forming five-member chelatin g rings,and three such rings are formed in each molecule.The coordination number of the metal ion is six and the coordination configuration of the cen-tral ion is octahedral.Specially,antimer configuration phenomenon is found in the molecu le.The complex is fur-ther characterized by element analysis and IR measurement s.The thermal decomposition mechanism is studied by using TG-DTG and DSC techni ques.CCDC:215675.
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)~~
文摘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Supported by Fundamental Research Funds for Central Universities(HEUCF201403002)Advanced Technique Project Funds of the Manufacture and Information Ministry
