WoS İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/394
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Article Citation - WoS: 8Citation - Scopus: 9Synthesis of Benzotriazole Functionalized ZIF-8 by Postsynthetic Modification for Enhanced CH4 and CO2 Uptakes(Elsevier, 2022-08) Erkartal, Mustafa; Incekara, Kaan; Sen, UnalIn this work, a series of functionalized ZIF-8 were synthesized via incorporation of benzotriazole ligands into the framework with a post-synthetic method. The crystal structure and porosity were preserved for all functionalized samples. Although a relatively low percentage of ligand exchange (approximately 10-22%) was observed due to steric and kinetic effects, a remarkable improvement was found in CO2 and CH4 uptake capacities due to the incorporation of more polar N sites into the structure and the change in pore size of the frameworks. The resulting ZIF-8-S5 exhibited 45.17(CO2) and 15.08 (CH4) cm(3) g(-1) at 273 K under 1.2 bar, which corresponds to an enhancement of 20 and 35% compared to pristine ZIF-8. Further, all functionalized samples showed the significant improvement of selective CO2 over N-2.Article Citation - WoS: 24Citation - Scopus: 24Proton-Conducting Blend Membranes of Nafion/Poly(Vinylphosphonic Acid) for Proton Exchange Membrane Fuel Cells(Springer, 2013-08-08) Sen, Unal; Acar, Oktay; Celik, Sevim Unugur; Bozkurt, Ayhan; Ata, Ali; Tokumasu, Takashi; Miyamoto, AkiraNafion/poly(vinylphosphonic acid) blends were synthesized and characterized in this work. Poly(vinylphosphonic acid), PVPA, was synthesized by the free-radical polymerization of vinylphosphonic acid. Then Nafion/PVPA blend membranes were prepared by means of film casting from Nafion/PVPA solutions with several molar ratios of PVPA repeat unit to - SO3H. Homogeneous Nafion/PVPA films were produced. Nafion-PVPA interactions were studied by Fourier transform infrared (FT-IR) spectroscopy. Thermal properties were investigated via thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The TGA results illustrated that all of these Nafion/PVPA electrolytes are thermally stable up to 400 degrees C. The membrane properties were further characterized by studying their morphologies using scanning electron microscopy (SEM). The proton conductivity of the Nafion/P(VPA)(3) blend membrane was 1.1x10(-5) S/cm in an anhydrous state at 130 degrees C. The conductivities of the blends increased by at least three orders of magnitude upon hydration, exceeding 10(-2) S/cm with RH=50 % at ambient temperature.Article Citation - WoS: 75Citation - Scopus: 80From 2-Methylimidazole to 1,2,3-Triazole: A Topological Transformation of ZIF-8 and ZIF-67 by Post-Synthetic Modification(Royal Soc Chemistry, 2017) Erkartal, Mustafa; Erkilic, Ufuk; Tam, Benjamin; Usta, Hakan; Yazaydin, Ozgur; Hupp, Joseph T.; Sen, UnalBridging ligand replacement in zeolitic imidazolate frameworks, ZIF-8 and ZIF-67, by 1,2,3-triazole was investigated. A complete substitution of 2-methylimidazole by 1,2,3-triazole resulted in a topological transformation of the parent framework from a sodalite (SOD) network to a diamond (DIA) network.