用微波辐射20 m in制备了钛柱撑活化膨润土,进行了XRD、钛含量、表面酸度及催化活性分析,结果表明,蒙脱石的层间距明显增大,在热稳定性、表面酸性、催化活性、钛含量等性能指标上,微波法均优于传统方法。随着钛含量的增加,样品的热稳定...用微波辐射20 m in制备了钛柱撑活化膨润土,进行了XRD、钛含量、表面酸度及催化活性分析,结果表明,蒙脱石的层间距明显增大,在热稳定性、表面酸性、催化活性、钛含量等性能指标上,微波法均优于传统方法。随着钛含量的增加,样品的热稳定性增强,用微波制备的钛柱撑膨润土催化剂使戊醇的转化率均高于常规方法。微波法制备钛柱撑膨润土是一种较好的方法。展开更多
Alkali metal K in exhaust gas has a deactivation effect on NH_(3)-SCR catalysts.In this work,it is discovered that the addition of Ho on CeTi catalyst can remarkably strengthen its K tolerance.The conclusions of Bruna...Alkali metal K in exhaust gas has a deactivation effect on NH_(3)-SCR catalysts.In this work,it is discovered that the addition of Ho on CeTi catalyst can remarkably strengthen its K tolerance.The conclusions of Brunauer-Emmett-Teller(BET),X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),NH_(3) temperature programmed desorption(NH_(3)-TPD)and H_(2)temperature programmed reduction(H_(2)-TPR)analyses demonstrate that the enhancement of K resistance mainly originates from its stronger surface acidity and redox capability,the higher concentration of Ce^(3+)species and surface chemisorbed oxygen.In situ DRIFT analysis reveals that the introduction of Ho on CeTi can remarkably improve the adsorption of NH_(3) and NO_(x) species on catalyst surface,accompanied by the intensified reactivity of ad-NH_(3) species,which should also administer to improve the K resistance.展开更多
A Ce（0.3）TiOxoxide carrier was synthesized via a sol–gel process,and Ce（0.3）TiOxsupported metal（M=Cd,Mn,Fe,W,Mo）oxide catalysts were prepared by the method of incipient-wetness impregnation.The catalysts were c...A Ce（0.3）TiOxoxide carrier was synthesized via a sol–gel process,and Ce（0.3）TiOxsupported metal（M=Cd,Mn,Fe,W,Mo）oxide catalysts were prepared by the method of incipient-wetness impregnation.The catalysts were characterized by means of X-ray diffraction（XRD）,Brunauer–Emmett–Teller（BET）analysis,scanning electron microscopy（SEM）,transmission electron microscopy（TEM）,Fourier transform infrared（FT–IR）spectroscopy,UV–Visdiffusereflectancespectroscopy（UV–VisDRS）,and Temperature-programmed reduction with H2（H2-TPR）.The catalytic activities for de-NO（x ）were evaluated by the NH3-SCR reaction.Among all the catalysts tested,the 2 wt.%Cd/Ce（0.3）TiOxcatalyst exhibited the best NH3-SCR performance,with a wide temperature window of 250–450℃ for NO conversion above 90%.Moreover,the catalyst showed N2 selectivity greater than 99%from 200 to 450℃.展开更多
Epoxidation of propylene to propylene oxide(PO)with hydrogen peroxide(HPPO)is an environmentally friendly and cost-efficient process in which titanosilicates are used as catalysts.Ti-MWW is a potential industrial cata...Epoxidation of propylene to propylene oxide(PO)with hydrogen peroxide(HPPO)is an environmentally friendly and cost-efficient process in which titanosilicates are used as catalysts.Ti-MWW is a potential industrial catalyst for this process,which involves the addition of HPPO to PO.The silanol groups generated during secondary crystallization unavoidably result in ring-opening of PO and inefficient decomposition of HPPO,which diminish the PO selectivity and the lifespan of Ti-MWW.To address this issue,we conducted post-treatment modifications of the structured Bf-Ti-MWW catalyst with potassium fluoride aqueous solutions.By quenching the silanol groups with potassium fluoride and implanting electron-withdrawing fluoride groups into the Ti-MWW framework,both the catalytic activity and HPPO utilization efficiency were increased.Moreover,the ring opening reaction of PO was prohibited.In a continuous fixed-bed liquid-phase propylene epoxidation reaction,the KF-treated structured Ti-MWW catalyst displayed an exceptionally long lifespan of 2700 h,with a PO yield of 590 g·kg^(-1)·h^(-1).展开更多
In this work,V/Ce-Ti catalysts were modified with different kinds of transition metals(Cu,Fe,Co,Mn) by sol-gel and impregnation methods.The NH_(3) oxidation performance of them was tested to select the most active cat...In this work,V/Ce-Ti catalysts were modified with different kinds of transition metals(Cu,Fe,Co,Mn) by sol-gel and impregnation methods.The NH_(3) oxidation performance of them was tested to select the most active catalyst in NH_(3)-selective catalytic oxidation(NH_(3)-SCO).The effect of NO,SO_(2) and H_(2)O was also investigated.The experimental results indicate that 1% Cu-V/Ce-Ti catalyst exhibits the most significant ability to remove slip ammonia discharged from coal-fired plants and its NH_(3) conversion efficiency reaches90% at 300℃.In additio n,97% NO_x can be removed when NO is introduced in the gas.Cu-V/Ce-Ti catalyst also obtains good resistance to H_(2)O and SO_(2).Based on the characterization experiment,the introduced Cu and V are highly dispersed on Ce-Ti catalyst and they can increase the redox properties and the number of acidic sites.Besides,the redox cycles among Cu,V and Ce species on Cu-V/Ce-Ti catalyst surface are conducive to generating more active oxygen and promoting the oxidation capacity of the catalyst.展开更多
文摘用微波辐射20 m in制备了钛柱撑活化膨润土,进行了XRD、钛含量、表面酸度及催化活性分析,结果表明,蒙脱石的层间距明显增大,在热稳定性、表面酸性、催化活性、钛含量等性能指标上,微波法均优于传统方法。随着钛含量的增加,样品的热稳定性增强,用微波制备的钛柱撑膨润土催化剂使戊醇的转化率均高于常规方法。微波法制备钛柱撑膨润土是一种较好的方法。
基金Project supported by the National Key R&D Program of China(2018YFB0605002)。
文摘Alkali metal K in exhaust gas has a deactivation effect on NH_(3)-SCR catalysts.In this work,it is discovered that the addition of Ho on CeTi catalyst can remarkably strengthen its K tolerance.The conclusions of Brunauer-Emmett-Teller(BET),X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),NH_(3) temperature programmed desorption(NH_(3)-TPD)and H_(2)temperature programmed reduction(H_(2)-TPR)analyses demonstrate that the enhancement of K resistance mainly originates from its stronger surface acidity and redox capability,the higher concentration of Ce^(3+)species and surface chemisorbed oxygen.In situ DRIFT analysis reveals that the introduction of Ho on CeTi can remarkably improve the adsorption of NH_(3) and NO_(x) species on catalyst surface,accompanied by the intensified reactivity of ad-NH_(3) species,which should also administer to improve the K resistance.
基金financially supported by the National Natural Science Foundation of China (Nos. 21673290, u1162103 and 21376261)the National Hi-Tech Research and Development Program (863) of China (No. 2015AA034603)the China Offshore Oil Fund (No. LHYJYKJSA2016002)
文摘A Ce（0.3）TiOxoxide carrier was synthesized via a sol–gel process,and Ce（0.3）TiOxsupported metal（M=Cd,Mn,Fe,W,Mo）oxide catalysts were prepared by the method of incipient-wetness impregnation.The catalysts were characterized by means of X-ray diffraction（XRD）,Brunauer–Emmett–Teller（BET）analysis,scanning electron microscopy（SEM）,transmission electron microscopy（TEM）,Fourier transform infrared（FT–IR）spectroscopy,UV–Visdiffusereflectancespectroscopy（UV–VisDRS）,and Temperature-programmed reduction with H2（H2-TPR）.The catalytic activities for de-NO（x ）were evaluated by the NH3-SCR reaction.Among all the catalysts tested,the 2 wt.%Cd/Ce（0.3）TiOxcatalyst exhibited the best NH3-SCR performance,with a wide temperature window of 250–450℃ for NO conversion above 90%.Moreover,the catalyst showed N2 selectivity greater than 99%from 200 to 450℃.
基金support from the National Key R&D Program of China(Grant Nos.2021YFA1501401 and 2023YFB3810602)the National Natural Science Foundation of China(Grant No.22222201)。
文摘Epoxidation of propylene to propylene oxide(PO)with hydrogen peroxide(HPPO)is an environmentally friendly and cost-efficient process in which titanosilicates are used as catalysts.Ti-MWW is a potential industrial catalyst for this process,which involves the addition of HPPO to PO.The silanol groups generated during secondary crystallization unavoidably result in ring-opening of PO and inefficient decomposition of HPPO,which diminish the PO selectivity and the lifespan of Ti-MWW.To address this issue,we conducted post-treatment modifications of the structured Bf-Ti-MWW catalyst with potassium fluoride aqueous solutions.By quenching the silanol groups with potassium fluoride and implanting electron-withdrawing fluoride groups into the Ti-MWW framework,both the catalytic activity and HPPO utilization efficiency were increased.Moreover,the ring opening reaction of PO was prohibited.In a continuous fixed-bed liquid-phase propylene epoxidation reaction,the KF-treated structured Ti-MWW catalyst displayed an exceptionally long lifespan of 2700 h,with a PO yield of 590 g·kg^(-1)·h^(-1).
基金Project supported by the National Key R&D Program of China (2019YFD1101300)。
文摘In this work,V/Ce-Ti catalysts were modified with different kinds of transition metals(Cu,Fe,Co,Mn) by sol-gel and impregnation methods.The NH_(3) oxidation performance of them was tested to select the most active catalyst in NH_(3)-selective catalytic oxidation(NH_(3)-SCO).The effect of NO,SO_(2) and H_(2)O was also investigated.The experimental results indicate that 1% Cu-V/Ce-Ti catalyst exhibits the most significant ability to remove slip ammonia discharged from coal-fired plants and its NH_(3) conversion efficiency reaches90% at 300℃.In additio n,97% NO_x can be removed when NO is introduced in the gas.Cu-V/Ce-Ti catalyst also obtains good resistance to H_(2)O and SO_(2).Based on the characterization experiment,the introduced Cu and V are highly dispersed on Ce-Ti catalyst and they can increase the redox properties and the number of acidic sites.Besides,the redox cycles among Cu,V and Ce species on Cu-V/Ce-Ti catalyst surface are conducive to generating more active oxygen and promoting the oxidation capacity of the catalyst.
