Research • Research Areas
Production of boron nitride nanotubes in thermal and microwave media and use of these for hydrogen storage.
Project Supervisors: Y. Yurum, Burcu Saner, Z. Ozlem Kocabas
Project 2009.C230, BOREN, National Boron Research Institute, 2009-2011.
Boron nitride (BN) nanotubes have recently attracted attention in various electronic and mechanical devices due to their excellent physical, chemical and electronic properties. Also, BN nanotubes can be used as a potential hydrogen storage material because of large surface area and potentially high binding energy. Hydrogen storage is a vital issue in the application of hydrogen as a future energy carrier. In addition, the usage of hydrogen requires an effective, safe, and stable storage medium. Since Turkey is one of the major natural resource of boron minerals, the synthesis techniques of BN nanotubes production via using boron minerals and their utilization in many engineering applications should be increased. Therefore, in this project, high yield synthesis of pure BN nanotubes at considerably low temperatures via thermal and microwave assisted CVD technique was proposed.
Development of Novel Materials for Proton Exchange Membrane Fuel Cells
The Synthesis of Low Cost Alternative Proton-Exchange Membranes for Fuel Cells and the Utilization of Conducting Polymers as the Catalyst Support.
Project Supervisors: S. A. Gursel, Y. Yurum
Project 108M333, TUBITAK, 2008-2011.
The increase of the consumption of energy and the limited resources of energy require the development of alternative energy resources, the storage of energy, its efficent usage and reducing the environmental wastes. Both academic and industrial studies have been performed for this purpose and the dependence on the fossil fuels has been tried to be reduced. Fuel cells expected as one of the most significant clean and environmental friendly sources for portable and stationary systems. Due to the high cost of the state of the art membranes such as Nafion® and the similar others and their poor performances at high temperatures, it is of interest to develop alternative membranes. Although the advantages of high operation temperatures are known, there are only a few important studies on the development and especially testing of proton exchange membranes for high temperature operation (80-150ºC). In this project, low cost proton-exchange membranes to be used in fuel cells operating at high temperatures (80-150 ºC) with high ionic conductivity, reasonable chemical and mechanical stability. Radiation-induced grafting method and subsequent doping with phosphoric acid, in order to make membranes ionic conducting, will be carried out for this purpose. N-vinyl-2-pyrrolidone, 2-vinyl pyridine, 4-vinyl pyridine will be employed as the monomer and poly(tetrafluoroethylene-co-hexafluoropropylene) (FEP) and poly(ethylene-alt-tetrafluoroethylene) (ETFE), will be employed as the base polymer films. The resultant membranes will be characterized ex situ for ionic conductivity, mechanical properties and diffusion properties. Then, the selected membranes will be characterized in situ in fuel cells for their performances and durability. Moreover, the deposition of catalyst on the membrane using the conducting polymers as the catalyst support, which has been applied only on Nafion® in the literature, will be employed for the prepared phosphoric acid based membranes. The selected membranes covered by conducting polymer and followed by the deposition of the catalyst, the modified membranes will be evaluated in single fuel cells and the influence of catalyst support will be investigated.
Synthesis and Characterization of Polyphosphazene based Proton Exchange Membranes for Fuel Cell Applications
Project Supervisor: S. A. Gursel
The world's growing energy needs and limited resources revealed the necessity of more environmentally friendly alternative energy production and storage methods. As well as the studies on secondary batteries for energy storage for this purpose, it has been widely accepted that the most advance technology is hydrogen energy system in order to decrease the dependency on fossil fuels and to ensure the increasing energy requirements without polluting the environment. In the late 1950s, the fuel cells being used by NASA for space technologies have been successfully used in industry as well as especially in the transport sector in recent years. Due to their poor performances as a result of dehydrration of Nafion® and related products at higher temperatures (100-140 °C), which are the most commonly used but expensive proton exchange membranes in fuel cell applications, they cannot fulfill the expected requirements in the especially automotive industry. In this context, alternative proton exchange membranes are still needed to be synthesized in line with these expectations. In this project, the synthesis and characterizations of new polyphosphazene based proton exchange membranes with high ionic conductivity and good mechanical properties are targetted. For this purpose, the synthesis of poly(dichlorophosphazene) (PDCP), which is the precursor polymer to be used for the synthesis of other substituted polyphosphazenes, will be performed. A series of polyphosphazenes will be synthesized then to serve as proton exchange membranes by functionalizing the precursor polymer with two different - heteroatom containing and not containing - aryl side chains in varying ratios via macromolecular substitution method. After the basic characterization of the polymers and membranes prepared by proper sulfonation or phosphonation of the polyphosphazenes, their ex situ ionic conductivities, mechanical properties and surface morphologieswill be investigated, and finally the selected membranes will be characterized in situ in fuel cells for their performances and impedance characteristics.
Project Supervisors: Y. Menceloglu, M. A. Gulgun, A. Taralp
Palladium Nanoparticles by Electrospinning from Polyacrylonitrile-co-acrylic Acid-PdCl2 Solutions. Relations between Preparation Conditions, Particle Size and Catalytic Activity, Demir, M. M., Gulgun, M. A., Menceloglu, Y. Z., Erman, B., Abramchuk, S. S., Khokhlov, A. R., Matveeva, V. G., Sulman, M. G., Macromolecules, 37, 1787-1792, 2004.
Metal Coated Nano Fibres, Demir, M. M., Gulgun, M. A., Menceloglu, Y. Z., WO 2005/021845 A1. Design and Synthesis of Novel Polymeric Materials for Proton Exchange Membrane Fuel Cell Applications, Birkan, B., Inceoglu, S., Menceloglu, Y. Z., Acar, M.H., Proceedings of the International Hydrogen Energy Congress and Exhibition IHEC 2005, Istanbul, Turkey, July 2005.
Removal of Contaminants
Combining genetic engineering methods with microbial desulfurization to improve the organic sulfur removal from Turkish and Bulgarian coals
Project Supervisors: Y. Yurum, G. Doganay Dinler (ITU), S.Marinov (Bulgarian Academy of Sciences)
Project 110M001, TUBITAK-Bulgarian Academy of Sciences, 2010-2013.
Coal has been used as a major source of energy for centuries. During coal combustion, sulfur content of coal combines with oxygen to form sulfur oxides which cause hazardous environmental problems such as acid rain. To decrease the sulfur dioxide emission to atmosphere, sulfur content of coal should be removed before combustion. Coal matrix comprises inorganic and organic sulfur compounds. Since inorganic sulfur compounds do not integrate with the coal matrix as the organic sulfur compounds do, removal of these compounds has a better removal rate compared to that of the organic sulfur compounds. There are several physical, chemical and biological methods used to remove sulfur compounds from coal. Today, physical and chemical methods are not sufficient enough for the removal of organic sulfur; therefore biodesulfurization becomes a promising tool to obtain higher yields in the removal of organic sulfur compounds with low-costs. Biodesulfurization is the consumption process of sulfur by the microorganisms, which are able to use sulfur in their metabolic pathways via their desulfurization enzymes (DszA, DszB, DszC and flavin reductase (DszD)). By this process, removal of sulfur compounds does not damage coal and the byproducts are harmless, so biodesulfurization is an economic and environmental method.
Determination of Coal Distribution by Integrated Seismic Methods and investigation of Coal Gas Potential in the Tertiary Soma Basin
Project Supervisors: S. Inan (MAM), Y.Yurum
Project No.108G0135, TUBITAK, 2008-2012.
The Neogene Basins of Turkey contain as much as 9 billion tons of lignite-rank coal. The Miocene Soma Basin, a rift basin trending NE-SW in the Aegean Extensional Province (EAP) of Western Turkey, is estimated to contain at the least one billion tons of lignite and about half of this reserve is present at depths greater than 600 m (Turkish Coal Enterprises, 2006). Miocene marl/limestone units and Pliocene clastics and volcanic tuffs overlie the Miocene coals of the Soma basin. In the Soma Basin, Turkish Coal Enterprises (TKI) has conducted open cut coal mining and underground coal mining activities for several decades in the Northern and Central part of the basin, respectively. Recently, coal exploration activities have been extended to the Southern part of the basin by means of exploratory drillings where the depth of coal is greater than 600 m; meaning good pressure environment for gas adsorption. In this context, two boreholes encountering a coal seam (M2) up to 20 m thick were evaluated. The M2 coal seam was encountered between 900 and 940 m depth in two boreholes drilled approximately 1 km apart. The wellhead gas content measurements (six core measurements from two boreholes) indicate 2- 4 m3 gas / ton coal is present in the coal recovered from 900 to 940 m below the surface. The rank of coal based on vitrinite reflectance measurements is lignite to sub-bituminous. The composition of the gas is dominantly methane (more than 99.4 %) and the 13C/12C isotope ratio of methane is 61 to 65 per mil. Considering the chemical composition of the gas and the del 13C isotope of the methane, the source of the coal gas is biogenic probably generated by bacteria that are introduced to the coal seam by fresh water following mainly the normal faults bordering the graben structure. In this project, by means of laboratory incubation the bacterial activity on coal and generation of bacterial gas will be investigated.