The effect of BaO doping to the Pt-Rh catalysts on its three-way catalytic activity and water-gas transfer was investigated. The results show that the light-off temperatures of hydrocarbon and carbon monoxide and nitr...The effect of BaO doping to the Pt-Rh catalysts on its three-way catalytic activity and water-gas transfer was investigated. The results show that the light-off temperatures of hydrocarbon and carbon monoxide and nitrogen oxides have little difference in the fresh catalysts. But after the hydrothermal-aged 5 h at 1000 ℃, the catalysts containing CeO2-ZrO2-BaO has lower light-off temperature and better catalytic activity than the catalysts containing BaO and CeO2-ZrO2,展开更多
The effects of BaO doping on the three-way catalytic activity of Pt-Rh catalyst and on water-gas shift were investigated. The results show that the light-off temperatures of hydrocarbon and carbon monoxide and nitroge...The effects of BaO doping on the three-way catalytic activity of Pt-Rh catalyst and on water-gas shift were investigated. The results show that the light-off temperatures of hydrocarbon and carbon monoxide and nitrogen oxides of the fresh catalysts slightly differ from those of the aged catalysts, and the catalysts containing CeO2-ZrO2-BaO have lower lightoff temperature and better catalytic activity than these containing BaO and CeO2-ZrO2 after hydrothermal aging for 5 h at 1000 ℃. The catalysts were characterized by means of the temperature-programmed reduction （TPR） in hydrogen and the temperature-programmed desorption （TPD） in oxygen. It is confirmed that the suggested route of CeO2-ZrO2-BaO by coprecipitation can improve the catalytic activity of catalysts.展开更多
The numerical simulation for temperature distribution of Pt-Rh alloy bushing was carried out using a thermal-electric module in ANSYS Workbench finite element analysis software.The effects of side wall thickness,plug ...The numerical simulation for temperature distribution of Pt-Rh alloy bushing was carried out using a thermal-electric module in ANSYS Workbench finite element analysis software.The effects of side wall thickness,plug thickness,the angle of two side walls and electrode structure on the uniformity of temperature distribution were investigated.Meanwhile,the contrastive analysis results of bushing with and without glass melt were discussed.The simulation results show that,when the homogeneous glass melt flows through bushing,the temperature difference between the center and both ends of bushing is decreased significantly,but the temperature distribution at both ends of bushing is still affected by heating non-uniformity of bushing.Compared with side wall thickness,plug thickness and the angle of two side walls,electrode structure plays a greater role in adjusting heating uniformity of bushing.展开更多
This work describes the environmentally friendly technology for oxidation of ammonia （NH3） to form nitrogen at temperatures range from 423K to 673K by selective catalytic oxidation （SCO） over a nanosized Pt- Rh/γ...This work describes the environmentally friendly technology for oxidation of ammonia （NH3） to form nitrogen at temperatures range from 423K to 673K by selective catalytic oxidation （SCO） over a nanosized Pt- Rh/γ-A12O3 catalyst prepared by the incipient wetness impregnation method of hexachloroplatinic acid （H2PtC16） and rhodium （Ⅲ） nitrate （Rh（NO3）3） with γ-A12O3 in a tubular fixed-bed flow quartz reactor （TFBR）. The characterization of catalysts were thoroughly measured using transmission electron microscopy （TEM）, three- dimensional excitation-emission fluorescent matrix （EEFM） spectroscopy, UV-Vis absorption, dynamic light- scattering （DLS）, zeta potential meter, and cyclic voltam- metry （CV）. The results demonstrated that at a temperature of 673K and an oxygen content of4%, approximately 99% of the NH3 was removed by catalytic oxidation over the nanosized Pt-Rh/γ-A12O3 catalyst. N2 was the main product in NH3-SCO process. Further, it reveals that the oxidation of NH3 was proceeds by the over-oxidation of NH3 into NO, which was conversely reacted with the NH3 to yield N2. Therefore, the application ofnanosized Pt-Rh/γ-A12O3 catalyst can significantly enhance the catalytic activity toward NH3 oxidation. One fluorescent peak for fresh catalyst was different with that of exhausted catalyst. It indicates that EEFM spectroscopy was proven to be an appropriate and effective method to characterize the Pt clusters in intrinsic emission from nanosized Pt-Rh/γ-A12O3 catalyst. Results obtained from the CV may explain the significant catalytic activity of the catalysts.展开更多
文摘The effect of BaO doping to the Pt-Rh catalysts on its three-way catalytic activity and water-gas transfer was investigated. The results show that the light-off temperatures of hydrocarbon and carbon monoxide and nitrogen oxides have little difference in the fresh catalysts. But after the hydrothermal-aged 5 h at 1000 ℃, the catalysts containing CeO2-ZrO2-BaO has lower light-off temperature and better catalytic activity than the catalysts containing BaO and CeO2-ZrO2,
基金Project supported by the National Natural Science Foundation of China (20273043) the National Nature Science KeyFoundation of China (20333030)
文摘The effects of BaO doping on the three-way catalytic activity of Pt-Rh catalyst and on water-gas shift were investigated. The results show that the light-off temperatures of hydrocarbon and carbon monoxide and nitrogen oxides of the fresh catalysts slightly differ from those of the aged catalysts, and the catalysts containing CeO2-ZrO2-BaO have lower lightoff temperature and better catalytic activity than these containing BaO and CeO2-ZrO2 after hydrothermal aging for 5 h at 1000 ℃. The catalysts were characterized by means of the temperature-programmed reduction （TPR） in hydrogen and the temperature-programmed desorption （TPD） in oxygen. It is confirmed that the suggested route of CeO2-ZrO2-BaO by coprecipitation can improve the catalytic activity of catalysts.
基金Funded by the State Key Laboratory of Silicate Materials for Architectures(Wuhan University of Technology)(No.SYSJJ2019-21)the National Key Research and Development Program of China(No.2016YFB0303700)。
文摘The numerical simulation for temperature distribution of Pt-Rh alloy bushing was carried out using a thermal-electric module in ANSYS Workbench finite element analysis software.The effects of side wall thickness,plug thickness,the angle of two side walls and electrode structure on the uniformity of temperature distribution were investigated.Meanwhile,the contrastive analysis results of bushing with and without glass melt were discussed.The simulation results show that,when the homogeneous glass melt flows through bushing,the temperature difference between the center and both ends of bushing is decreased significantly,but the temperature distribution at both ends of bushing is still affected by heating non-uniformity of bushing.Compared with side wall thickness,plug thickness and the angle of two side walls,electrode structure plays a greater role in adjusting heating uniformity of bushing.
文摘This work describes the environmentally friendly technology for oxidation of ammonia （NH3） to form nitrogen at temperatures range from 423K to 673K by selective catalytic oxidation （SCO） over a nanosized Pt- Rh/γ-A12O3 catalyst prepared by the incipient wetness impregnation method of hexachloroplatinic acid （H2PtC16） and rhodium （Ⅲ） nitrate （Rh（NO3）3） with γ-A12O3 in a tubular fixed-bed flow quartz reactor （TFBR）. The characterization of catalysts were thoroughly measured using transmission electron microscopy （TEM）, three- dimensional excitation-emission fluorescent matrix （EEFM） spectroscopy, UV-Vis absorption, dynamic light- scattering （DLS）, zeta potential meter, and cyclic voltam- metry （CV）. The results demonstrated that at a temperature of 673K and an oxygen content of4%, approximately 99% of the NH3 was removed by catalytic oxidation over the nanosized Pt-Rh/γ-A12O3 catalyst. N2 was the main product in NH3-SCO process. Further, it reveals that the oxidation of NH3 was proceeds by the over-oxidation of NH3 into NO, which was conversely reacted with the NH3 to yield N2. Therefore, the application ofnanosized Pt-Rh/γ-A12O3 catalyst can significantly enhance the catalytic activity toward NH3 oxidation. One fluorescent peak for fresh catalyst was different with that of exhausted catalyst. It indicates that EEFM spectroscopy was proven to be an appropriate and effective method to characterize the Pt clusters in intrinsic emission from nanosized Pt-Rh/γ-A12O3 catalyst. Results obtained from the CV may explain the significant catalytic activity of the catalysts.
