A sulfonated poly（ether ether ketone） （SPEEK） membrane with a fairly high degree of sulfonation （DS） can swell excessively and even dissolve at high temperature. To solve these problems, insolvable functionalize...A sulfonated poly（ether ether ketone） （SPEEK） membrane with a fairly high degree of sulfonation （DS） can swell excessively and even dissolve at high temperature. To solve these problems, insolvable functionalized silica powder with sulfonic acid groups （SiOx-S） was added into the SPEEK matrix （DS = 55.1%） to prepare SPEEK/ SiOx-S composite membranes. The decrease in both the swelling degree and the methanol permeability of the membranes was a dose-dependent result of addition of the SiOx-S powder. Pure SPEEK membrane swelled 52.6% at 80℃, whereas the SPEEK/SiOx-S （15%, by mass） membrane swelled only 27.3% at the same temperature. From room temperature to 80℃, all SPEEK/SPEEK/SiOx-S composite membranes had methanol permeability of about one order of magnitude lower than that ofNafion115. Compared with pure SPEEK membranes, the addition of the SiOx-S powder not only leads to higher proton conductivity, but also increases the dimensional stability at higher temperatures, and greater proton conductivity can be achieved at higher temperature. The SPEEK/SiO4-S （20%, by mass） membrane could withstand temperature up to 145℃, at which in 100% relative humidity （RH） its proton conductivity exceeded slightly that of Nafion 1 15 membrane and reached 0.17 S·cm^-1, while pure SPEEK membrane dissolved at 90℃. The SPEEK/SiOx-S composite membranes are promising for use in direct methanol fuel cells because of their good dimensional stability, high proton conductivity, and low methanol permeability.展开更多
A unique sulfonated polyaniline/vanadate composite was synthesized and utilized as a composite anode in microbial fuel cells on ocean floor (BMFCs). X-ray diffraction (XRD) and thermogravimetric analysis (TGA) were em...A unique sulfonated polyaniline/vanadate composite was synthesized and utilized as a composite anode in microbial fuel cells on ocean floor (BMFCs). X-ray diffraction (XRD) and thermogravimetric analysis (TGA) were employed to characterize its chemical composition and morphology. Wettability of the composite anodes decreases due to the addition of polytetrafluoroethylene (PTFE). The electrochemical behavior of the composite anodes was investigated by means of linear sweep voltammetry and Tafel plot measurements. Compared with the plain graphite anode,the composite anode significantly improves the power density,5.5-fold higher,reaching 187.1 mW/m2 and gives a 27-fold higher exchange current density and a higher kinetic activity. A novel synergistic mechanism between sulfonated polyaniline and vanadate is proposed to explain the excellent electrochemical performance. This composite thus has great potential to be used as an anode material for a high-power BMFC.展开更多
A novel approach is designed to optimize the synthesis of sulfonic-functionalized silica material. Results from 29Si and 27AI NMR suggest that the AI acts as the bridging atom connecting the methanesulfonate and silic...A novel approach is designed to optimize the synthesis of sulfonic-functionalized silica material. Results from 29Si and 27AI NMR suggest that the AI acts as the bridging atom connecting the methanesulfonate and silica matrix. Further pyridine-FTIR spectra followed by catalytic activity tests demonstrate that compared with previous methods, our new approach results in higher Lewis acid site concentration, higher thermal stability and superior catalytic activity. Moreover, the whole catalysis preparation procedure is environmentally friendly. Specifically, the silica matrix is synthesized through hydrolysis of tetrae- thylorthosilicate employing formic acid as hydro-catalyst, in which no surfactant species or precursors were involved.展开更多
基金Supported by the State Key Development Program for Basic Research of China （2008CB617502）, the National Natural Science Foundation of China （20606025）, and Program for Changjiang Scholars and Innovative Research Team in University of China （IRT0641）.
文摘A sulfonated poly（ether ether ketone） （SPEEK） membrane with a fairly high degree of sulfonation （DS） can swell excessively and even dissolve at high temperature. To solve these problems, insolvable functionalized silica powder with sulfonic acid groups （SiOx-S） was added into the SPEEK matrix （DS = 55.1%） to prepare SPEEK/ SiOx-S composite membranes. The decrease in both the swelling degree and the methanol permeability of the membranes was a dose-dependent result of addition of the SiOx-S powder. Pure SPEEK membrane swelled 52.6% at 80℃, whereas the SPEEK/SiOx-S （15%, by mass） membrane swelled only 27.3% at the same temperature. From room temperature to 80℃, all SPEEK/SPEEK/SiOx-S composite membranes had methanol permeability of about one order of magnitude lower than that ofNafion115. Compared with pure SPEEK membranes, the addition of the SiOx-S powder not only leads to higher proton conductivity, but also increases the dimensional stability at higher temperatures, and greater proton conductivity can be achieved at higher temperature. The SPEEK/SiO4-S （20%, by mass） membrane could withstand temperature up to 145℃, at which in 100% relative humidity （RH） its proton conductivity exceeded slightly that of Nafion 1 15 membrane and reached 0.17 S·cm^-1, while pure SPEEK membrane dissolved at 90℃. The SPEEK/SiOx-S composite membranes are promising for use in direct methanol fuel cells because of their good dimensional stability, high proton conductivity, and low methanol permeability.
基金supported by the Scientific and Technological Development Plan Project of Shandong Province, China (2008GG10007003)the Key Laboratory of Marine Environment & Ecology, Ministry of Education (2008010)the Key Laboratory of Submarine Geoscience and Exploring Technology of Ministry of Education, Ocean University of China (2008-01)
文摘A unique sulfonated polyaniline/vanadate composite was synthesized and utilized as a composite anode in microbial fuel cells on ocean floor (BMFCs). X-ray diffraction (XRD) and thermogravimetric analysis (TGA) were employed to characterize its chemical composition and morphology. Wettability of the composite anodes decreases due to the addition of polytetrafluoroethylene (PTFE). The electrochemical behavior of the composite anodes was investigated by means of linear sweep voltammetry and Tafel plot measurements. Compared with the plain graphite anode,the composite anode significantly improves the power density,5.5-fold higher,reaching 187.1 mW/m2 and gives a 27-fold higher exchange current density and a higher kinetic activity. A novel synergistic mechanism between sulfonated polyaniline and vanadate is proposed to explain the excellent electrochemical performance. This composite thus has great potential to be used as an anode material for a high-power BMFC.
文摘A novel approach is designed to optimize the synthesis of sulfonic-functionalized silica material. Results from 29Si and 27AI NMR suggest that the AI acts as the bridging atom connecting the methanesulfonate and silica matrix. Further pyridine-FTIR spectra followed by catalytic activity tests demonstrate that compared with previous methods, our new approach results in higher Lewis acid site concentration, higher thermal stability and superior catalytic activity. Moreover, the whole catalysis preparation procedure is environmentally friendly. Specifically, the silica matrix is synthesized through hydrolysis of tetrae- thylorthosilicate employing formic acid as hydro-catalyst, in which no surfactant species or precursors were involved.
