The effects of gas compositions and reaction conditions on NO conversion by positive streamer discharge were experimentally investigated by using a link tooth wheel-cylinder reactor.The results showed that NO conversi...The effects of gas compositions and reaction conditions on NO conversion by positive streamer discharge were experimentally investigated by using a link tooth wheel-cylinder reactor.The results showed that NO conversion increased with increasing O_(2) concentration and NH3 concen-tration,but decreased with increasing inlet NO concentration and gas flow rate.The addition of CO_(2) or H_(2)O to the feed gas promoted NO conversion by increasing the maximum discharge voltage,and NH4NO3 was formed in the presence of NH_(3).There was a most suitable range interval between discharge tooth wheels if both NO conversion and energy consumption were considered.Increasing applied voltage resulted in the increase in the amount of O_(3) generated by streamer discharge.展开更多
Improving energy efficiency in plasma NO removal is a critical issue.When the surface dielectric barrier discharge(SDBD)device is considered as a combination of multiple plasma actuators,the induced plasma aerodynamic...Improving energy efficiency in plasma NO removal is a critical issue.When the surface dielectric barrier discharge(SDBD)device is considered as a combination of multiple plasma actuators,the induced plasma aerodynamic effect cannot be ignored,which can affect the mass transfer,then affect the chemical reactions.Five SDBD devices with different electrode arrangements are studied for NO conversion.They correspond to different flow patterns.We find that the energy efficiency in an SDBD device with a common structure(Type 1)is 28%lower than that in SDBD devices with a special arrangement(Types 2–5).Two reasons may explain the results.First,fewer active species are produced in Type 1 because the development of discharge is hindered by the mutually exclusive electric field forces caused by the symmetrically distributed charged particles.Second,the plasma wind induced by the plasma actuator can enhance the mass and heat transfer.The mixing of reactants and products is better in Types 2–5 than Type 1 due to higher turbulence kinetic energy.展开更多
Pd/YZ-Al2O3 （Y and Zr modified Al2O3, and hereafter, labelled as A1） catalysts with 4 wt% additive CeO2 and/or La2O3 were prepared and characterized by X-ray photoelectron spectroscopy （XPS）, NO-temperature progra...Pd/YZ-Al2O3 （Y and Zr modified Al2O3, and hereafter, labelled as A1） catalysts with 4 wt% additive CeO2 and/or La2O3 were prepared and characterized by X-ray photoelectron spectroscopy （XPS）, NO-temperature programmed desorption （NO-TPD）, Nz-adsorption/desorption （Branauer-Emmet-Teller BET method）, X-ray diffraction （XRD） and CO-chemisorption. Catalytic activities for CH4, CO and NO conversion were tested in a gas mixture simulated the emissions from natural gas vehicles （NGVs） operated under stoichiometric conditions. The results indicated that all catalysts exhibited excellent catalytic performances for CH4 and CO oxidation and the promoting effect of CeO2 or La2O3 was significant for NO conversion. XPS results showed that the electron density around Pd was increased by CeO2 and/or La2O3, the binding energy of Pd 3d decreased as the order： Pd/Al 〉 Pd/Ce/Al 〉 Pd/La/Al 〉 Pd/CeLa/Al. The electron-rich Pd showed Rh-like catalytic properties which exhibited good activity for the reduction of NO. NO-TPD results showed that the addition of CeO2 and/or La2O3 increased NO adsorption on surface, and promoted the conversion of NO.展开更多
A series of attapulgite （ATP） supported perovskite-type La1-xCexMnO3 ix=0-0.2） nanocomposites were prepared by a sol-gel method. The samples were characterized by X-ray diffraction, transmission elec- tron microsco...A series of attapulgite （ATP） supported perovskite-type La1-xCexMnO3 ix=0-0.2） nanocomposites were prepared by a sol-gel method. The samples were characterized by X-ray diffraction, transmission elec- tron microscopy, Fourier-transform infrared spectroscopy, H2 temperature-programmed reduction, and temperature-programmed desorption of NH3. Their selective catalytic reduction of NO with NH3 was evaluated in the low-temperature range. The impact of the doping fraction of Ce4＋ on the NO conversion was investigated. The results indicated that the La1-xCexMnO3 nanoparticles with a size of ca. 15 nm were uniformly immobilized on the surface of ATP with a loading amount of 20wt%. The highest conversion rate of NO reached 98.6% when the doping fraction x was O.1, while the ATP support supplied a high surface areas facilitating the nanoparticles dispersion as well as the gas adsorption. Incorporation of an appropriate amount of Ce4＋ in the La3＋ site resulted in a high degree of reduction by the active perovskite species with enhanced catalytic activity.展开更多
A series of phosphorylation and blank CeSn_（0.8）W_（0.6）O_x/TiAl_（0.2）Si_（0.1）O_y catalysts prepared by extrusion molding were tested for NH_3-SCR of NO, and were characterized by techniques of X-ray diffractio...A series of phosphorylation and blank CeSn_（0.8）W_（0.6）O_x/TiAl_（0.2）Si_（0.1）O_y catalysts prepared by extrusion molding were tested for NH_3-SCR of NO, and were characterized by techniques of X-ray diffraction（XRD）, Brumauer-Emmett-Teller（N_2-BET）, environmental scanning electron microscope（ESEM）, temperature programmed reduction（H_2-TPR） and temperature programmed desorption（NH_3-TPD）. Effects of phosphorylation on catalytic activity and sulfur-resisting performance of the CeSn_（0.8）W_（0.6）O_x/TiAl_（0.2）Si_（0.1）O_y for NH_3-SCR of NO were mainly studied. Results showed that the phosphorylation improved the catalytic activity and sulfur-resisting performance in an active temperature window of 300–440 °C, and the phosphorylation catalyst with 0.4 wt.% H_3PO_4 exhibited the best catalytic performance and the strongest sulfur-resisting performance. Analysis showed that the phosphorylation increased specific surface area, enhanced the surface acidity and improved redox properties.展开更多
MnO_(x)-CeO_(x)/ACFN were prepared by the impregnation method and used as catalyst for selective catalytic reduction of NO with NH_(3) at 80℃-150℃.The catalyst was characterized by N_(2)-BET,scanning electron micros...MnO_(x)-CeO_(x)/ACFN were prepared by the impregnation method and used as catalyst for selective catalytic reduction of NO with NH_(3) at 80℃-150℃.The catalyst was characterized by N_(2)-BET,scanning electron microscopy(SEM)and Fourier transform infrared spectroscopy(FT-IR).The fraction of the mesopore and the oxygen functional groups on the surface of activated carbon fiber(ACF)increased after the treatment with nitric acid,which was favorable to improve the catalytic activities of MnO_(x)-CeO_(x)/ACFN.The experimental results show that the conversion of NO is nearly 100%in the range 100℃-150℃under the optimal preparation conditions of MnO_(x)-CeO_(x)/ACFN.In addition,the effects of a series of performance parameters,including initial NH3 concentration,NO concentration and O_(2) concentration,on the conversion of NO were studied.展开更多
The promotional effect of the interaction between titania and ceria on the catalytic performance for selective reduction of NO was studied.The catalysts,CeO 2,TiO 2,CeO 2 /TiO 2 and Ti x Ce 1-x O 2,were synthesized an...The promotional effect of the interaction between titania and ceria on the catalytic performance for selective reduction of NO was studied.The catalysts,CeO 2,TiO 2,CeO 2 /TiO 2 and Ti x Ce 1-x O 2,were synthesized and tested in NH 3-Selective catalytic reduction（SCR） of NO,and the samples were characterized by the Brunaller,Emmett and Teller（BET absorbed gas N 2）,X-ray diffraction（XRD）,high resolution transmission electron microscopy（HR-TEM）,and temperature programmed desorption（TPD NH 3） techniques.The improvement mechanism of the interaction between the titania and ceria had been explored and discussed from two aspects of micro-structure and surface acidity.The interaction between the titania and ceria greatly improved the catalytic activity but had little effect on the active temperature.It was first reported that the acid amount determined the catalytic activity and the acid strength determined the active temperature for NH 3-SCR of NO.展开更多
基金This work was supported by the National Natural Science Foundation of China(Grant No.20677004).
文摘The effects of gas compositions and reaction conditions on NO conversion by positive streamer discharge were experimentally investigated by using a link tooth wheel-cylinder reactor.The results showed that NO conversion increased with increasing O_(2) concentration and NH3 concen-tration,but decreased with increasing inlet NO concentration and gas flow rate.The addition of CO_(2) or H_(2)O to the feed gas promoted NO conversion by increasing the maximum discharge voltage,and NH4NO3 was formed in the presence of NH_(3).There was a most suitable range interval between discharge tooth wheels if both NO conversion and energy consumption were considered.Increasing applied voltage resulted in the increase in the amount of O_(3) generated by streamer discharge.
基金supported by the National Natural Science Foundation of China(60906053,61204069,61274118,61306144,61504079,and 11605112)Scientific and Innovative Action Plan of Shanghai(15DZ1160800 and 17XD1702400)China Postdoctoral Science Foundation(2016 M601595).
文摘Improving energy efficiency in plasma NO removal is a critical issue.When the surface dielectric barrier discharge(SDBD)device is considered as a combination of multiple plasma actuators,the induced plasma aerodynamic effect cannot be ignored,which can affect the mass transfer,then affect the chemical reactions.Five SDBD devices with different electrode arrangements are studied for NO conversion.They correspond to different flow patterns.We find that the energy efficiency in an SDBD device with a common structure(Type 1)is 28%lower than that in SDBD devices with a special arrangement(Types 2–5).Two reasons may explain the results.First,fewer active species are produced in Type 1 because the development of discharge is hindered by the mutually exclusive electric field forces caused by the symmetrically distributed charged particles.Second,the plasma wind induced by the plasma actuator can enhance the mass and heat transfer.The mixing of reactants and products is better in Types 2–5 than Type 1 due to higher turbulence kinetic energy.
基金supported by the Key Program of National Natural Science Foundation of China (20333030)the National High Technology Research and Development Program of China (863 Program, No. 2006AA06Z347)the National Natural Science Foundation of China (No. 20773090)
文摘Pd/YZ-Al2O3 （Y and Zr modified Al2O3, and hereafter, labelled as A1） catalysts with 4 wt% additive CeO2 and/or La2O3 were prepared and characterized by X-ray photoelectron spectroscopy （XPS）, NO-temperature programmed desorption （NO-TPD）, Nz-adsorption/desorption （Branauer-Emmet-Teller BET method）, X-ray diffraction （XRD） and CO-chemisorption. Catalytic activities for CH4, CO and NO conversion were tested in a gas mixture simulated the emissions from natural gas vehicles （NGVs） operated under stoichiometric conditions. The results indicated that all catalysts exhibited excellent catalytic performances for CH4 and CO oxidation and the promoting effect of CeO2 or La2O3 was significant for NO conversion. XPS results showed that the electron density around Pd was increased by CeO2 and/or La2O3, the binding energy of Pd 3d decreased as the order： Pd/Al 〉 Pd/Ce/Al 〉 Pd/La/Al 〉 Pd/CeLa/Al. The electron-rich Pd showed Rh-like catalytic properties which exhibited good activity for the reduction of NO. NO-TPD results showed that the addition of CeO2 and/or La2O3 increased NO adsorption on surface, and promoted the conversion of NO.
文摘A series of attapulgite （ATP） supported perovskite-type La1-xCexMnO3 ix=0-0.2） nanocomposites were prepared by a sol-gel method. The samples were characterized by X-ray diffraction, transmission elec- tron microscopy, Fourier-transform infrared spectroscopy, H2 temperature-programmed reduction, and temperature-programmed desorption of NH3. Their selective catalytic reduction of NO with NH3 was evaluated in the low-temperature range. The impact of the doping fraction of Ce4＋ on the NO conversion was investigated. The results indicated that the La1-xCexMnO3 nanoparticles with a size of ca. 15 nm were uniformly immobilized on the surface of ATP with a loading amount of 20wt%. The highest conversion rate of NO reached 98.6% when the doping fraction x was O.1, while the ATP support supplied a high surface areas facilitating the nanoparticles dispersion as well as the gas adsorption. Incorporation of an appropriate amount of Ce4＋ in the La3＋ site resulted in a high degree of reduction by the active perovskite species with enhanced catalytic activity.
基金Project supported by the National Natural Science Foundation of China(51272105)Jiangsu Provincial Science and Technology Supporting Program(BE2013718)+1 种基金Research Subject of Environmental Protection Department of Jiangsu Province of China(2013006)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘A series of phosphorylation and blank CeSn_（0.8）W_（0.6）O_x/TiAl_（0.2）Si_（0.1）O_y catalysts prepared by extrusion molding were tested for NH_3-SCR of NO, and were characterized by techniques of X-ray diffraction（XRD）, Brumauer-Emmett-Teller（N_2-BET）, environmental scanning electron microscope（ESEM）, temperature programmed reduction（H_2-TPR） and temperature programmed desorption（NH_3-TPD）. Effects of phosphorylation on catalytic activity and sulfur-resisting performance of the CeSn_（0.8）W_（0.6）O_x/TiAl_（0.2）Si_（0.1）O_y for NH_3-SCR of NO were mainly studied. Results showed that the phosphorylation improved the catalytic activity and sulfur-resisting performance in an active temperature window of 300–440 °C, and the phosphorylation catalyst with 0.4 wt.% H_3PO_4 exhibited the best catalytic performance and the strongest sulfur-resisting performance. Analysis showed that the phosphorylation increased specific surface area, enhanced the surface acidity and improved redox properties.
基金supported by the National Natural Science Foundation of China(Grant No.90610018)Tianjin Provincial Natural Science Foundation(Grant No.06YFJMJC-06200)“100 projects”of Creative Research for the Undergraduates of Nankai University.
文摘MnO_(x)-CeO_(x)/ACFN were prepared by the impregnation method and used as catalyst for selective catalytic reduction of NO with NH_(3) at 80℃-150℃.The catalyst was characterized by N_(2)-BET,scanning electron microscopy(SEM)and Fourier transform infrared spectroscopy(FT-IR).The fraction of the mesopore and the oxygen functional groups on the surface of activated carbon fiber(ACF)increased after the treatment with nitric acid,which was favorable to improve the catalytic activities of MnO_(x)-CeO_(x)/ACFN.The experimental results show that the conversion of NO is nearly 100%in the range 100℃-150℃under the optimal preparation conditions of MnO_(x)-CeO_(x)/ACFN.In addition,the effects of a series of performance parameters,including initial NH3 concentration,NO concentration and O_(2) concentration,on the conversion of NO were studied.
基金supported by National Natural Science Foundation of China (21106071 and 50872052)National High-Tech Research and Development Program of China (863 Program,2009AA05Z313)+1 种基金New Teachers' Fund for Doctor Stations the Ministry of Education of China(20113221120004)Research Subject of Environmental Protection Department of Jiangsu Province of China (201016)
文摘The promotional effect of the interaction between titania and ceria on the catalytic performance for selective reduction of NO was studied.The catalysts,CeO 2,TiO 2,CeO 2 /TiO 2 and Ti x Ce 1-x O 2,were synthesized and tested in NH 3-Selective catalytic reduction（SCR） of NO,and the samples were characterized by the Brunaller,Emmett and Teller（BET absorbed gas N 2）,X-ray diffraction（XRD）,high resolution transmission electron microscopy（HR-TEM）,and temperature programmed desorption（TPD NH 3） techniques.The improvement mechanism of the interaction between the titania and ceria had been explored and discussed from two aspects of micro-structure and surface acidity.The interaction between the titania and ceria greatly improved the catalytic activity but had little effect on the active temperature.It was first reported that the acid amount determined the catalytic activity and the acid strength determined the active temperature for NH 3-SCR of NO.
