In this paper,automobile exhaust particles of Gol and Santana 3000 were studied by spectromicroscopy.The STXM results show that the single particulate is sized at 500 nm,with the mass distribution reducing towards the...In this paper,automobile exhaust particles of Gol and Santana 3000 were studied by spectromicroscopy.The STXM results show that the single particulate is sized at 500 nm,with the mass distribution reducing towards the center.The N 1s NEXAFS spectra of automobile exhaust particles have similar structure with those of nitrates,which can be deduced as the main chemical species of nitrogen in automobile exhaust particles.There are minor amounts of ammoniums and organic nitrogen compounds in automobile exhaust particles.A single Gol automobile exhaust particle was stack scanned in the energy range of 396-416 eV.By principal component analysis and cluster analysis,it can be deduced that there are main three chemical species of nitrogen.The particle surface consists of mainly nitrates,the inside consists of mainly ammonium and organic nitrogen compounds,and the middle layer is an intergradation consisting of mainly nitrates and organic nitrogen compounds.展开更多
According to experiments and the phenomena that tailpipes often have dirty particulate matter, this paper takes dynamic theory analysis as its study aim, beginning with the description method of multiphase gas distrib...According to experiments and the phenomena that tailpipes often have dirty particulate matter, this paper takes dynamic theory analysis as its study aim, beginning with the description method of multiphase gas distribution differential equation. According to the characteristics that exhaust gas will flow with high velocity in a tailpipe, it is supposed that gas mass that differ largely will layer when flowing with high velocity in a tailpipe. This means the exhaust gas is mixed with particulate matter, gas with large mass （CO2,HC,NOx） and gas with small mass （CO,H2O,N2,O2）. The interface of two phase fluid will be become clearer as it flows in the pipe for a long distance. The fluid continuous equation between gas phase and solid phase and the mathematical relationship between the geometry parameter and the flowing are established by a multiphase gas flowing theory. Analyzing the interface and state of layers will provide a basic theory for developing a catalytic converter with high efficiency.展开更多
Palladium catalysts are supported on TiO2, ZrO2, A12O3, Zro.sAlo.501.75 and TiO2-Zro.sAlo.501.75 prepared by co-precipitation method, re- spectively. Catalytic activities for methane and CO oxidation are evaluated in ...Palladium catalysts are supported on TiO2, ZrO2, A12O3, Zro.sAlo.501.75 and TiO2-Zro.sAlo.501.75 prepared by co-precipitation method, re- spectively. Catalytic activities for methane and CO oxidation are evaluated in a gas mixture that simulated the exhaust from lean-burn natural gas vehicles （NGVs）. Pd/TiO2-Zro.sAlo.501.75 performs the best catalytic activity among the tested five catalysts. For CH4, the light-off temperature （Tso） is 254 ℃, and the complete conversion temperature （Tgo） is 280 ℃; for CO, Tso is 84 ℃, and Tgo was 96 ℃. Various techniques, including N2 adsorption-desorption, X-ray diffraction （XRD）, H2-temperature-programmed reduction （H2-TPR）, X-ray photoelec- tron spectroscopy （XPS）, and scanning electron microscopy （SEM） are employed to characterize the effect of supports on the physicochemical properties of prepared catalysts. N2 adsorption-desorption and SEM show that TiO2-Zro.5Al0.501.75 expresses uniform nano-particles and large meso-pore diameters of 26 nm. H2-TPR and XRD indicate that PdO is well dispersed on the supports and strongly interacted with each other. The results of XPS show that the electron density around PdO and the proportion of active oxygen on TiO2-Zro.sAl0.501.75 are maxima among the five supports.展开更多
The study of oxidized-reduced properties of modified natural zeolites from deposits of Georgia--clinoptilolite and mordenite in reaction of reduction NO with H2, NH3, CH4 and especially CO was carried out for the purp...The study of oxidized-reduced properties of modified natural zeolites from deposits of Georgia--clinoptilolite and mordenite in reaction of reduction NO with H2, NH3, CH4 and especially CO was carried out for the purpose to obtain effective catalyst for afterburning of toxic components of automobile exhaust. The activity of zeolites essentially depends on nature of cation and temperature of reaction and slightly depends on structure of zeolite and ratio of reactants. The introduction of copper and iron ions in preliminary decationated clinoptilolite and mordenite causes growth of conversion degree of nitrogen and carbon monoxides almost on a degree, especially in low temperature interval. The reaction between NO and CO molecules proceeds in coordinative sphere of TM cations through formation ofnitrosyl and carbonyl complexes.展开更多
With a rapid increase in volume of ve-hicles in the world,the polution causedby the automobile exhausted gas has be-come more and more serious.This problemhas brought to our government’s atten-tion.In Beijing,regulat...With a rapid increase in volume of ve-hicles in the world,the polution causedby the automobile exhausted gas has be-come more and more serious.This problemhas brought to our government’s atten-tion.In Beijing,regulations regardingthe supervision of the exhaust have beenissued.At the Fifth National Meeting on RECatalytic purification of Automobile Ex-haust held in Beijing 1989,the partici-pants from institutes,universities,andfactories all over the country reportedand discussed the methods of purifica-展开更多
This work elucidates the synthesis and characterization of copper ions incorporated ceria(Ce1-xCuxO2)nanocatalysts with 3 D flower-like and nanocrystalline morphology for the purification of automobile exhausts. XRD a...This work elucidates the synthesis and characterization of copper ions incorporated ceria(Ce1-xCuxO2)nanocatalysts with 3 D flower-like and nanocrystalline morphology for the purification of automobile exhausts. XRD and Raman results confirm the presence of copper ions in ceria. The 3 D flower-like and nanocrystalline morphology exhibited by these catalysts were seen by FESEM images. HRTEM and SAED results confirm that(100) plane is dominantly presented in 3 D flower-like Ce1-xCuxO2catalysts when compared to nanocrystalline morphology. The textural properties of synthesized catalysts was done with the help of N2 sorption study, which confirms that flower-like Ce1-xCuxO2catalysts show high surface area and pore volume. The existence of Ce3+, Ce4+, Cu+and Cu2+ions in the catalyst were examined by XPS and DR UV-Vis techniques. Oxygen storage capacity(OSC) of the catalysts was studied by H2-TPR analysis. These characterization results elucidate the presence of dominant active sites(Ce3+, Ce4+, Cu+and Cu2+) and {100} plane in the flower-like morphology compared to nanocrystalline. The catalytic activity of synthesized Ce1-xCuxO2catalysts was tested for removal of CO, HCxand NO gases from automobile emission with respect to the copper content and morphology. The obtained results indicate that the presence of optimum amount of copper in ceria with flower-like morphology is essential for the removal of CO, HCxand NO at low temperature via redox process, which is due to the presence of active sites on the dominant {100} plane.展开更多
基金Project supported by the Main Direction Program of Knowledge Innovation of Chinese Academy of Sciences,China (Grant No. KJCX2-YW-N38) the Special Foundation for Major Basic Research Program of Shanghai,China (Grant No. 08JC1422600)+1 种基金the Knowledge Innovation Program of the Chinese Academy of Sciences (Grant No. 54095501D)Shanghai Natural Science Fundation (Grant No. 10ZR1436600)
文摘In this paper,automobile exhaust particles of Gol and Santana 3000 were studied by spectromicroscopy.The STXM results show that the single particulate is sized at 500 nm,with the mass distribution reducing towards the center.The N 1s NEXAFS spectra of automobile exhaust particles have similar structure with those of nitrates,which can be deduced as the main chemical species of nitrogen in automobile exhaust particles.There are minor amounts of ammoniums and organic nitrogen compounds in automobile exhaust particles.A single Gol automobile exhaust particle was stack scanned in the energy range of 396-416 eV.By principal component analysis and cluster analysis,it can be deduced that there are main three chemical species of nitrogen.The particle surface consists of mainly nitrates,the inside consists of mainly ammonium and organic nitrogen compounds,and the middle layer is an intergradation consisting of mainly nitrates and organic nitrogen compounds.
文摘According to experiments and the phenomena that tailpipes often have dirty particulate matter, this paper takes dynamic theory analysis as its study aim, beginning with the description method of multiphase gas distribution differential equation. According to the characteristics that exhaust gas will flow with high velocity in a tailpipe, it is supposed that gas mass that differ largely will layer when flowing with high velocity in a tailpipe. This means the exhaust gas is mixed with particulate matter, gas with large mass （CO2,HC,NOx） and gas with small mass （CO,H2O,N2,O2）. The interface of two phase fluid will be become clearer as it flows in the pipe for a long distance. The fluid continuous equation between gas phase and solid phase and the mathematical relationship between the geometry parameter and the flowing are established by a multiphase gas flowing theory. Analyzing the interface and state of layers will provide a basic theory for developing a catalytic converter with high efficiency.
基金supported by the National Natural Science Foundation of China(21173153)
文摘Palladium catalysts are supported on TiO2, ZrO2, A12O3, Zro.sAlo.501.75 and TiO2-Zro.sAlo.501.75 prepared by co-precipitation method, re- spectively. Catalytic activities for methane and CO oxidation are evaluated in a gas mixture that simulated the exhaust from lean-burn natural gas vehicles （NGVs）. Pd/TiO2-Zro.sAlo.501.75 performs the best catalytic activity among the tested five catalysts. For CH4, the light-off temperature （Tso） is 254 ℃, and the complete conversion temperature （Tgo） is 280 ℃; for CO, Tso is 84 ℃, and Tgo was 96 ℃. Various techniques, including N2 adsorption-desorption, X-ray diffraction （XRD）, H2-temperature-programmed reduction （H2-TPR）, X-ray photoelec- tron spectroscopy （XPS）, and scanning electron microscopy （SEM） are employed to characterize the effect of supports on the physicochemical properties of prepared catalysts. N2 adsorption-desorption and SEM show that TiO2-Zro.5Al0.501.75 expresses uniform nano-particles and large meso-pore diameters of 26 nm. H2-TPR and XRD indicate that PdO is well dispersed on the supports and strongly interacted with each other. The results of XPS show that the electron density around PdO and the proportion of active oxygen on TiO2-Zro.sAl0.501.75 are maxima among the five supports.
文摘The study of oxidized-reduced properties of modified natural zeolites from deposits of Georgia--clinoptilolite and mordenite in reaction of reduction NO with H2, NH3, CH4 and especially CO was carried out for the purpose to obtain effective catalyst for afterburning of toxic components of automobile exhaust. The activity of zeolites essentially depends on nature of cation and temperature of reaction and slightly depends on structure of zeolite and ratio of reactants. The introduction of copper and iron ions in preliminary decationated clinoptilolite and mordenite causes growth of conversion degree of nitrogen and carbon monoxides almost on a degree, especially in low temperature interval. The reaction between NO and CO molecules proceeds in coordinative sphere of TM cations through formation ofnitrosyl and carbonyl complexes.
文摘With a rapid increase in volume of ve-hicles in the world,the polution causedby the automobile exhausted gas has be-come more and more serious.This problemhas brought to our government’s atten-tion.In Beijing,regulations regardingthe supervision of the exhaust have beenissued.At the Fifth National Meeting on RECatalytic purification of Automobile Ex-haust held in Beijing 1989,the partici-pants from institutes,universities,andfactories all over the country reportedand discussed the methods of purifica-
基金the UGC meritorious fellowship for providing financial support
文摘This work elucidates the synthesis and characterization of copper ions incorporated ceria(Ce1-xCuxO2)nanocatalysts with 3 D flower-like and nanocrystalline morphology for the purification of automobile exhausts. XRD and Raman results confirm the presence of copper ions in ceria. The 3 D flower-like and nanocrystalline morphology exhibited by these catalysts were seen by FESEM images. HRTEM and SAED results confirm that(100) plane is dominantly presented in 3 D flower-like Ce1-xCuxO2catalysts when compared to nanocrystalline morphology. The textural properties of synthesized catalysts was done with the help of N2 sorption study, which confirms that flower-like Ce1-xCuxO2catalysts show high surface area and pore volume. The existence of Ce3+, Ce4+, Cu+and Cu2+ions in the catalyst were examined by XPS and DR UV-Vis techniques. Oxygen storage capacity(OSC) of the catalysts was studied by H2-TPR analysis. These characterization results elucidate the presence of dominant active sites(Ce3+, Ce4+, Cu+and Cu2+) and {100} plane in the flower-like morphology compared to nanocrystalline. The catalytic activity of synthesized Ce1-xCuxO2catalysts was tested for removal of CO, HCxand NO gases from automobile emission with respect to the copper content and morphology. The obtained results indicate that the presence of optimum amount of copper in ceria with flower-like morphology is essential for the removal of CO, HCxand NO at low temperature via redox process, which is due to the presence of active sites on the dominant {100} plane.
