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Dyck A.,NEXT ENERGY EWE Forschungszentrum fur Energietechnologie EV
Fuel Cells Bulletin | Year: 2014

Know-how from a variety of disciplines is required to design highly efficient and long-lasting fuel cell systems. To this end, the NEXT ENERGY Fuel Cells Division is focused on three research topics - micro-CHP systems, materials, and characterisation - which work in close cooperation and profit from the prompt exchange of knowledge and experimental results. A central aspect of this research is the acquisition of real data for household energy systems from their application in the field. © 2014 Elsevier Ltd.

Luo J.,Catholic University of Leuven | Luo J.,NEXT ENERGY EWE Forschungszentrum fur Energietechnologie EV | Tan T.V.,Catholic University of Leuven | Conrad O.,University of Cape Town | Vankelecom I.F.J.,Catholic University of Leuven
Physical Chemistry Chemical Physics | Year: 2012

The solvation effect of 1H-1,2,4-triazole towards imidazolium methanesulfonate was studied by blending imidazolium methanesulfonate and 1H-1,2,4-triazole. Upon addition of 1H-1,2,4-triazole, the melting point of imidazolium methanesulfonate was lowered to less than 100 °C while maintaining the high ionic conductivity for a wide composition range of the blend. The ionic conductivity of the blend can be adequately described by using the Vogel-Fulcher-Tamman equation. A vehicle mechanism is postulated to govern the proton conduction for the blend. The contribution of protons to the ionic conductivity was corroborated electrochemically. The blend exhibited electrochemical activities for H2 oxidation and O2 reduction at a Pt electrode, as well as a wide electrochemical window. Therefore, suitable blends can possibly serve as electrolytes for polymer electrolyte membrane fuel cells operating under non-humidifying conditions. The solvation effect studied herein suggests a promising approach to a wider application area of protic ionic liquids. © 2012 the Owner Societies.

Kwan A.J.,California Institute of Technology | Kwan A.J.,NEXT ENERGY EWE Forschungszentrum fur Energietechnologie EV | Kwan A.J.,United States Agency for International Development | Chan A.W.H.,California Institute of Technology | And 6 more authors.
Atmospheric Chemistry and Physics | Year: 2012

Peroxy radical reactions (RO 2 + RO 2) from the NO 3-initiated oxidation of isoprene are studied with both gas chromatography and a chemical ionization mass spectrometry technique that allows for more specific speciation of products than in previous studies of this system. We find high nitrate yields (∼ 80%), consistent with other studies. We further see evidence of significant hydroxyl radical (OH) formation in this system, which we propose comes from RO 2 + HO 2 reactions with a yield of ∼38-58%. An additional OH source is the second generation oxidation of the nitrooxyhydroperoxide, which produces OH and a dinitrooxyepoxide with a yield of ∼35%. The branching ratio of the radical propagating, carbonyl-and alcohol-forming, and organic peroxide-forming channels of the RO 2 + RO 2 reaction are found to be ∼18-38%, ∼59-77%, and ∼3-4%, respectively. HO 2 formation in this system is lower than has been previously assumed. Addition of RO 2 to isoprene is suggested as a possible route to the formation of several isoprene C10-organic peroxide compounds (ROOR). The nitrooxy, allylic, and C5 peroxy radicals present in this system exhibit different behavior than the limited suite of peroxy radicals that have been studied to date. © 2012 Author(s).

Luo J.,Catholic University of Leuven | Luo J.,NEXT ENERGY EWE Forschungszentrum fur Energietechnologie EV | Conrad O.,University of Cape Town | Vankelecom I.F.J.,Catholic University of Leuven
Journal of Materials Chemistry | Year: 2012

Trioctylphosphonium triflate, trioctylammonium triflate, triphenylphosphonium triflate and triphenylammonium triflate were synthesized and characterized. It was found that phosphonium-based protic ionic liquids (PILs) exhibit higher thermal stability and ionic conductivity than the corresponding ammonium-based PILs, no matter whether the P and N center atoms are bonded to the electron-donating octyl groups or the electron-withdrawing phenyl groups. The ion conduction behavior of the PILs can be adequately described by the Vogel-Fulcher-Tamman (VFT) equation. The higher ionic conductivity of phosphonium-based PILs may be attributed to their weaker hydrogen bond and Coulombic interactions as well as higher carrier ion concentrations, indicated by infrared analysis, lattice potential energy estimation and VFT fitting results. Interestingly, the stronger hydrogen bonds inside trioctylammonium triflate may lead to a much decreased melting point. Furthermore, compared with electron-withdrawing phenyl, electron-donating octyl enhanced the thermal stability of the PILs. © 2012 The Royal Society of Chemistry.

Luo J.,NEXT ENERGY EWE Forschungszentrum fur Energietechnologie EV | Luo J.,Catholic University of Leuven | Luo J.,Carl von Ossietzky University | Hu J.,NEXT ENERGY EWE Forschungszentrum fur Energietechnologie EV | And 7 more authors.
Journal of Materials Chemistry | Year: 2011

Protic ionic liquid and ionic melts were prepared from the combination of methanesulfonic acid (CH3SO3H) and 1H-1,2,4-triazole (C2H3N3) at various molar ratios. The thermal properties, crystal structure, acid-base interactions, ionic conductivity, proton conduction behavior and electrochemical stability of the system were studied. The equimolar composition, 1,2,4-triazolium methanesulfonate (C 2H4N3 +·CH3SO 3 - (1)), was a proton transfer salt with a melting point of around 134 °C. Single crystal and powder XRD data, as well as TGA results, revealed that the base-rich region was a mixture of 1 and 1H-1,2,4-triazole. Infrared analysis and single crystal data suggested that the C2H3N3-CH3SO3H system exists in a strongly hydrogen-bonded network. Systematic investigation of the ionic conductivity showed that the ionic conductivity reached local maxima at the compositions of [C2H3N3]/[CH 3SO3H] = 10/90 and 80/20, respectively, while it exhibited a local minimum at the equimolar composition. The temperature dependence of the ionic conductivity was found to obey the Vogel-Fulcher-Tamman (VFT) equation. The fitting of the conductivity data to the VFT equation showed that the carrier ion concentration versus the mole fraction of 1H-1,2,4-triazole exhibited a volcano shape. In addition, the C2H3N3-CH 3SO3H system showed adequate electrochemical stability under PEMFC conditions as measured by linear sweep voltammetry. The relatively high ionic conductivity, wide electrochemical window and good thermal stability demonstrated that the C2H3N3-CH 3SO3H system is a suitable candidate for high temperature PEMFC electrolytes. © 2011 The Royal Society of Chemistry.

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