DECNAHED · Development of Composite Nanomaterials for Hydrogen Energy Devices

Development of Composite Nanomaterials for Hydrogen Energy Devices

Polymer membranes are widely used and increasingly find more applications. The increase is mainly in hi-tech area. Very important are following applications in energy and environmental chemistry: 1) hydrogen fuel cells and electrolysers, 2) water removal from bioethanol, 3) ion-selective water cleaning, 4) gas (CO2, CO, H2) separation from solutions and gas mixtures. In polymer industry traditionally the most widely used are using typical polymer properties – the viscosity of polymer is decreasing by increasing the temperature and obtained fluid mass is easy to process. However, this preparation method is not applicable for polymer materials in previously mentioned applications because of the lack of the material homogeneity. Typically they are prepared by casting. We developed in cooperation with industry the automated equipment for laboratory casting in order to improve the quality of research. New generation membrane reactors are demanding membranes with much higher thickness precision and homogeneity, which could not be provided by traditional casting. In case of mass transport, the increase of the membrane thickness will reasonably decrease the mass flow. At the same time, for thin membrane the requirements to the homogeneity and quality are higher. Structural defects will decrease the membrane selectivity and will greatly lower mechanical strength. It is relevant to produce thin polymer membranes with complex structure (composition with asymmetric pores with pre-determined geometry, multilayer structures) and without mechanical defects. New laboratory technique allowed to compare the traditional approaches with the more advanced and result was very interesting from point view of science as well. It showed that the hand casted membrane consists of different structural sectors, which physical properties might be very different. For long term application in devices it is very important to achieve much higher homogeneity. In our studies we try to understand the reason behind the formation of those structural varieties. Is it possible to homogenise them by using more sophisticated technique? How it will influence the properties of membrane? By involving students in research it was possible also to extend the research area and pay attention to the new class of composites with ionic liquids and zirconium oxide particles. They might significantly improve the membrane properties. However, it was also find that not always they behave like traditional organic solvents or inorganic additives and might surprise the researcher. It was planned to achieve following objectives: 1) to develop novel prototype proton conducting membranes based on double-crosslinked SPEEK; 2) to develop novel proton conducting composite membranes combining non-fluorinated polymer (PEEK) and inorganic nanoparticles (zirconium phosphate, metal oxides) with tailored surface; 3) to provide the analysis of the structure, physico-chemical and physical properties of membranes; 4) to assemble and test the membrane electrode assemblies for PEM and DMFC applications using novel membranes; 5) to introduce the computer modeling approaches in material research. All objectives have been reached. The results of research are published in scientific publications and presented in numerous scientific conferences. According to Google Scholar the h-index 12 and 611 citations (47 % added after 2007). More than 10 postgraduate students have been supervised and new teaching courses for BSc and MSc students were introduced. Students are more excited about opportunities to assemble fuel cell model and test new materials in real action. Reintegration grant helped to position myself as researcher and in teaching position, involving students in my research. It is time to look for opportunities to participate in international research projects and the developed new laboratory technique for membrane preparation might be interesting for other researchers. Contact details: Dr chem Guntars Vaivars Senior researcher. Laboratory of Hydrogen and Gaseous sensors. Institute of Solid State Physics. University of Latvia, Kengaraga 8, LV-1063, Riga, Latvia. Docent in Physical Chemistry. University of Latvia, Department of Chemistry. Kr. Valdemara 48, Riga, Latvia. E-mail: Guntars. Vaivars@cfi. lu. lv

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