Iron-based perovskite-type compounds modified by Ru were prepared through sol-gel process to study its catalytic activity of NOx direct decomposition at low temperature and evaluate the conversion of NO under the expe...Iron-based perovskite-type compounds modified by Ru were prepared through sol-gel process to study its catalytic activity of NOx direct decomposition at low temperature and evaluate the conversion of NO under the experimental conditions. The catalytic activity of La 0.9Ce 0.1Fe 0.8-nCo 0.2RunO3 （n=0.01,0.03,0.05,0.07,0.09）series for the NO, NO-CO two components, CO-HC-NO three components were also analyzed. The catalytic investigation evidenced that the presence of Ru is necessary for making highly activity in decomposition of nitric oxide even at low temperature（400 ℃）and La 0.9Ce 0.9Fe 0.75Co 0.2Ru 0.05O3 （n=0.05） has better activity in all the samples, the conversion of it is 58.5%. With the reducing gas（CO,C3H6）added into the gas, the catalyst displayed very high activity in decomposition of NO and the conversion of it is 80% and 92.5% separately.展开更多
Quantum chemical calculation was carried out to choose a promoter which can reduce the poisoning of V2O5/TiO2 catalysts by SO2. Several atoms were chosen as candidates and new catalysts were synthesized by impregnatio...Quantum chemical calculation was carried out to choose a promoter which can reduce the poisoning of V2O5/TiO2 catalysts by SO2. Several atoms were chosen as candidates and new catalysts were synthesized by impregnation method. The NOx conversion rate was measured at temperatures between 100 and 400 ℃ and poisoning effect was investigated. The most promising candidate promoter, Se, was excluded because of its high vapor pressure. On the other hand, Sb shows best promoting properties. Sb promoted catalyst reaches the maximum NOx conversion rate at 250 ℃. It also shows considerably enhanced resistance to poisoning of V2O5/TiO2 catalysts by SO2.展开更多
The activated carbons from coal were treated by HNO3 （named as NAC） and used as carriers to load 7% Ce （named as Ce（0.07）/NAC） by impregnation method. The physical and chemical properties were investigated by th...The activated carbons from coal were treated by HNO3 （named as NAC） and used as carriers to load 7% Ce （named as Ce（0.07）/NAC） by impregnation method. The physical and chemical properties were investigated by thermogravimetric-differential thermal analysis （TG-DTA）, Brunauer-Emmett-Teller （BET）, X-ray diffraction （XRD）, X-ray photoelectron spectra （XPS）, scanning electron microscopy （SEM） and NH3-temperature programmed desorption （NH3-TPD） and NO-temperature programmed desorption techniques. The catalytic activities of Ce（0.07）/NAC were evaluated for the low temperature selective catalytic reduction （SCR） of NO with C3H6 using temperature-programmed reaction （TP-reaction） in NO, C3H6, 02 and N2 as a balance. The results showed that the specific surface area of Ce（0.07）/NAC was 850.8 m2/g and less than NAC, but Ce oxides could be dispersed highly on the acti- vated carbons. Ce oxides could change acid sites and NO adsorption as well as oxygen-containing functional groups of activated car- bons, and Ce4＋ and Ce〉 coexisted in catalysts. The conversion of NO with C3H6 achieved 70% at 280 ~C over Ce（0.07）/NAC, but with the increase of 02 concentration, heat accumulation and nonselective combustion were exacerbated, which could cause surface ashing and roughness, resulting in a sharp decrease of catalytic activities. The optimum 02 concentration used in the reaction system was 3% and achieved the high conversion of NO and the widest temperature window. The conversion of NO was closely related to the NO concentrations and [NO]/[C3H6] ratios, and the stoichiometric number was just close to 2：1, but the presence of H20 could af- fect the denitration efficiency of catalyst.展开更多
The preparation and catalytic activity of ferric oxide and its composite oxides supported gold catalysts for low-temperature CO oxidation were investigated detailedly, and characterized extensively by XRD, XPS, TPR, E...The preparation and catalytic activity of ferric oxide and its composite oxides supported gold catalysts for low-temperature CO oxidation were investigated detailedly, and characterized extensively by XRD, XPS, TPR, EC and XAFS techniques. It was found that containing highly dispersed Au of partially oxidized state, these nano-structured oxides supported Au/Fe2O3 and Au/NiFe2O4 catalysts had higher low-temperature activities. The possible catalytic active center is the gold of partially oxidized state (Auζ+).展开更多
基金Sponsored by the National Natural Science Foundation of China(Grant No.20271019 and 20576027), Natural Science Foundation of Heilongjiang Prov-ince(Grant No.B200504), Postdoctoral Foundationof Heilongjiang Province(Grant No.LBH-Z05066) and Education Department Foundation of Hei-longjiang Province(Grant No.11511270).
文摘Iron-based perovskite-type compounds modified by Ru were prepared through sol-gel process to study its catalytic activity of NOx direct decomposition at low temperature and evaluate the conversion of NO under the experimental conditions. The catalytic activity of La 0.9Ce 0.1Fe 0.8-nCo 0.2RunO3 （n=0.01,0.03,0.05,0.07,0.09）series for the NO, NO-CO two components, CO-HC-NO three components were also analyzed. The catalytic investigation evidenced that the presence of Ru is necessary for making highly activity in decomposition of nitric oxide even at low temperature（400 ℃）and La 0.9Ce 0.9Fe 0.75Co 0.2Ru 0.05O3 （n=0.05） has better activity in all the samples, the conversion of it is 58.5%. With the reducing gas（CO,C3H6）added into the gas, the catalyst displayed very high activity in decomposition of NO and the conversion of it is 80% and 92.5% separately.
基金This research was supportedby a grant fromKorea Institute of Science and Technology(2E19500).
文摘Quantum chemical calculation was carried out to choose a promoter which can reduce the poisoning of V2O5/TiO2 catalysts by SO2. Several atoms were chosen as candidates and new catalysts were synthesized by impregnation method. The NOx conversion rate was measured at temperatures between 100 and 400 ℃ and poisoning effect was investigated. The most promising candidate promoter, Se, was excluded because of its high vapor pressure. On the other hand, Sb shows best promoting properties. Sb promoted catalyst reaches the maximum NOx conversion rate at 250 ℃. It also shows considerably enhanced resistance to poisoning of V2O5/TiO2 catalysts by SO2.
基金Project supported by National Natural Science Foundation of China(50808127)the Sichuan Provincial Science and Technology Agency Public Research Projects(2012GZX0028)
文摘The activated carbons from coal were treated by HNO3 （named as NAC） and used as carriers to load 7% Ce （named as Ce（0.07）/NAC） by impregnation method. The physical and chemical properties were investigated by thermogravimetric-differential thermal analysis （TG-DTA）, Brunauer-Emmett-Teller （BET）, X-ray diffraction （XRD）, X-ray photoelectron spectra （XPS）, scanning electron microscopy （SEM） and NH3-temperature programmed desorption （NH3-TPD） and NO-temperature programmed desorption techniques. The catalytic activities of Ce（0.07）/NAC were evaluated for the low temperature selective catalytic reduction （SCR） of NO with C3H6 using temperature-programmed reaction （TP-reaction） in NO, C3H6, 02 and N2 as a balance. The results showed that the specific surface area of Ce（0.07）/NAC was 850.8 m2/g and less than NAC, but Ce oxides could be dispersed highly on the acti- vated carbons. Ce oxides could change acid sites and NO adsorption as well as oxygen-containing functional groups of activated car- bons, and Ce4＋ and Ce〉 coexisted in catalysts. The conversion of NO with C3H6 achieved 70% at 280 ~C over Ce（0.07）/NAC, but with the increase of 02 concentration, heat accumulation and nonselective combustion were exacerbated, which could cause surface ashing and roughness, resulting in a sharp decrease of catalytic activities. The optimum 02 concentration used in the reaction system was 3% and achieved the high conversion of NO and the widest temperature window. The conversion of NO was closely related to the NO concentrations and [NO]/[C3H6] ratios, and the stoichiometric number was just close to 2：1, but the presence of H20 could af- fect the denitration efficiency of catalyst.
基金BEPC Synchrotron Radiation Laboratory of the Institute of High Energy Physics, Chinese Academy of Sciences.
文摘The preparation and catalytic activity of ferric oxide and its composite oxides supported gold catalysts for low-temperature CO oxidation were investigated detailedly, and characterized extensively by XRD, XPS, TPR, EC and XAFS techniques. It was found that containing highly dispersed Au of partially oxidized state, these nano-structured oxides supported Au/Fe2O3 and Au/NiFe2O4 catalysts had higher low-temperature activities. The possible catalytic active center is the gold of partially oxidized state (Auζ+).
