Vapor permeation has potential applications in the separation of organic solvent-water mixtures.Adsorption property of organic vapor influences mainly the membrane selectivity in vapor permeation.The adsorption isothe...Vapor permeation has potential applications in the separation of organic solvent-water mixtures.Adsorption property of organic vapor influences mainly the membrane selectivity in vapor permeation.The adsorption isotherms of water,acetone, methanol, ethanol and isopropanol vapors on γ -Al 2O 3 membrane were measured by methods of dynamic chromatography.The parameters of the relevant Pickett isotherms were calculated.展开更多
The preferential oxidation of CO （CO‐PROX） is a hot topic because of its importance in pro‐ton‐exchange membrane fuel cells （PEMFCs）. Au catalysts are highly active in CO oxidation. Howev‐er, their activities ...The preferential oxidation of CO （CO‐PROX） is a hot topic because of its importance in pro‐ton‐exchange membrane fuel cells （PEMFCs）. Au catalysts are highly active in CO oxidation. Howev‐er, their activities still need to be improved at the PEMFC operating temperatures of 80–120 ＆#176;C. In the present study, Au nanoparticles of average size 2.6 nm supported on ceria‐modified Al2O3 were synthesized and characterized using powder X‐ray diffraction, nitrogen physisorption, transmission electron and scanning transmission electron microscopies, temperature‐programmed hydrogen reduction （H2‐TPR）, Raman spectroscopy, and in situ diffuse‐reflectance infrared Fourier‐transform spectroscopy. Highly dispersed Au nanoparticles and strong structures formed by Au–support in‐teractions were the main active species on the ceria surface. The Raman and H2‐TPR results show that the improved catalytic performance of the Au catalysts can be attributed to enhanced strong metal–support interactions and the reducibility caused by ceria doping. The formation of oxygen vacancies on the catalysts increased their activities in CO‐PROX. The synthesized Au catalysts gave excellent catalytic performances with high CO conversions （＆gt;97%） and CO2 selectivities （＆gt;50%） in the temperature range 80–150 ＆#176;C.展开更多
Recently,a one-pot self-assembly method was proposed for the synthesis of mesoporous Al2O3 and MOx-Al2O3 composite materials.However,few attempts have been made to use mesoporous MOx-Al2O3 composites to support metal ...Recently,a one-pot self-assembly method was proposed for the synthesis of mesoporous Al2O3 and MOx-Al2O3 composite materials.However,few attempts have been made to use mesoporous MOx-Al2O3 composites to support metal oxides for catalysis.In the present work,mesoporous MOx-Al2O3（M = Mn,Fe,Co,Ni,Cu,Ba）materials were prepared by a one-pot self-assembly method using Pluronic P123 as a structure-directing agent.The obtained mesoporous materials were loaded with Rh2O3 nanoparticles via impregnation with Rh（NO3）3 followed by calcination in air at 500°C.The resulting catalysts were characterized by X-ray diffraction,N2 adsorption-desorption measurements,transmission electron microscopy,inductively coupled plasma optical emission spectrometry,X-ray photoelectron spectroscopy,and their catalytic activity and stability for CO oxidation and N2O decomposition were tested.The Rh2O3 nanoparticles were found to be on the order of1 nm in size and were highly dispersed on the high surface area mesoporous MOx-Al2O3 supports.A number of the Rh2O3/mesoporous MOx-Al2O3 catalysts exhibited higher catalytic activity than the Rh2O3/mesoporous Al2O3 prepared for comparison.展开更多
文摘Vapor permeation has potential applications in the separation of organic solvent-water mixtures.Adsorption property of organic vapor influences mainly the membrane selectivity in vapor permeation.The adsorption isotherms of water,acetone, methanol, ethanol and isopropanol vapors on γ -Al 2O 3 membrane were measured by methods of dynamic chromatography.The parameters of the relevant Pickett isotherms were calculated.
基金supported by the National Basic Research Program of China (973 Program, 2013CB934104)the National Natural Science Founda-tion of China (21225312, U1303192)~~
文摘The preferential oxidation of CO （CO‐PROX） is a hot topic because of its importance in pro‐ton‐exchange membrane fuel cells （PEMFCs）. Au catalysts are highly active in CO oxidation. Howev‐er, their activities still need to be improved at the PEMFC operating temperatures of 80–120 ＆#176;C. In the present study, Au nanoparticles of average size 2.6 nm supported on ceria‐modified Al2O3 were synthesized and characterized using powder X‐ray diffraction, nitrogen physisorption, transmission electron and scanning transmission electron microscopies, temperature‐programmed hydrogen reduction （H2‐TPR）, Raman spectroscopy, and in situ diffuse‐reflectance infrared Fourier‐transform spectroscopy. Highly dispersed Au nanoparticles and strong structures formed by Au–support in‐teractions were the main active species on the ceria surface. The Raman and H2‐TPR results show that the improved catalytic performance of the Au catalysts can be attributed to enhanced strong metal–support interactions and the reducibility caused by ceria doping. The formation of oxygen vacancies on the catalysts increased their activities in CO‐PROX. The synthesized Au catalysts gave excellent catalytic performances with high CO conversions （＆gt;97%） and CO2 selectivities （＆gt;50%） in the temperature range 80–150 ＆#176;C.
基金supported by the National Natural Science Foundation of China (21177028)~~国家自然科学基金(21177028)
文摘Recently,a one-pot self-assembly method was proposed for the synthesis of mesoporous Al2O3 and MOx-Al2O3 composite materials.However,few attempts have been made to use mesoporous MOx-Al2O3 composites to support metal oxides for catalysis.In the present work,mesoporous MOx-Al2O3（M = Mn,Fe,Co,Ni,Cu,Ba）materials were prepared by a one-pot self-assembly method using Pluronic P123 as a structure-directing agent.The obtained mesoporous materials were loaded with Rh2O3 nanoparticles via impregnation with Rh（NO3）3 followed by calcination in air at 500°C.The resulting catalysts were characterized by X-ray diffraction,N2 adsorption-desorption measurements,transmission electron microscopy,inductively coupled plasma optical emission spectrometry,X-ray photoelectron spectroscopy,and their catalytic activity and stability for CO oxidation and N2O decomposition were tested.The Rh2O3 nanoparticles were found to be on the order of1 nm in size and were highly dispersed on the high surface area mesoporous MOx-Al2O3 supports.A number of the Rh2O3/mesoporous MOx-Al2O3 catalysts exhibited higher catalytic activity than the Rh2O3/mesoporous Al2O3 prepared for comparison.
