Browsing by Author "Baysal, Akin"
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Article Citation Count: 25Amine-functionalized graphene nanosheet-supported PdAuNi alloy nanoparticles: efficient nanocatalyst for formic acid dehydrogenation(Royal Soc Chemistry, 2018) Kaya, Murat; Yurderi, Mehmet; Kaya, Murat; Aydemir, Murat; Baysal, Akin; Durap, Feyyaz; Zahmakiran, Mehmet; Chemical EngineeringFormic acid (HCOOH), a major by-product of biomass processing with high energy density, stability and non-toxicity, has a great potential as a safe and a convenient liquid hydrogen (H-2) storage material for combustion engines and fuel cell applications. However, high-purity hydrogen release from the catalytic decomposition of aqueous formic acid solution at desirable rates under mild conditions stands as a major challenge that needs to be solved for the practical use of formic acid in on-demand hydrogen generation systems. Described herein is a new nanocatalyst system comprised of 3-aminopropyltriethoxysilane-functionalized graphene nanosheet-supported PdAuNi alloy nanoparticles (PdAuNi/f-GNS), which can reproducibly be prepared by following double solvent method combined with liquid-phase chemical reduction, all at room temperature. PdAuNi/f-GNS selectively catalyzes the decomposition of aqueous formic acid through the dehydrogenation pathway (similar to 100% H-2 selectivity), in the absence of any promoting additives (alkali formates, Bronsted bases, Lewis bases, etc.). PdAuNi/f-GNS nanocatalyst provides CO-free H-2 generation with a turnover frequency of 1090 mol H-2 mol metal(-1) h(-1) in the additive-free dehydrogenation of formic acid at almost complete conversion (>= 92%) even at room temperature. The catalytic activity provided by PdAuNi/f-GNS nanocatalyst is higher than those obtained with the heterogeneous catalysts reported to date for the additive-free dehydrogenation of formic acid. Moreover, PdAuNi/f-GNS nanoparticles show high durability against sintering, clumping and leaching throughout the catalytic runs, so that the PdAuNi/f-GNS nanocatalyst retains almost its inherent catalytic activity and selectivity at the end of the 10th recycle.Article Citation Count: 15Cobalt nanoparticles supported on alumina nanofibers (Co/Al2O3): Cost effective catalytic system for the hydrolysis of methylamine borane(Pergamon-elsevier Science Ltd, 2019) Baguc, Ismail Burak; Yurderi, Mehmet; Bulut, Ahmet; Celebi, Metin; Kanberoglu, Gulsah Saydan; Zahmakiran, Mehmet; Baysal, AkinAmongst different amine-borane derivatives, methylamine-borane (CH3NH2BH3) seems to be one of the capable aspirants in the storing of hydrogen attributable to its high hydrogen capacity, stability and aptitude to generate hydrogen through its catalytic hydrolysis reaction under ambient conditions. In this research paper, we report that cobalt nano-particles supported on alumina nanofibers (Co/Al2O3) are acting as active nanocatalyst for catalytic hydrolysis of methylamine-borane. Co/Al2O3 nanocatalyst was fabricated by double-solvent method followed with wet-chemical reduction, and was characterized by utilizing various spectroscopic methods and imaging techniques. The results gathered from these analyses showed that the formation Al2O3 nanofibers supported cobalt(0) nanoparticles with a mean diameter of 3.9 +/- 1.2 nm. The catalytic feat of these cobalt nanoparticles was scrutinized in the catalytic hydrolysis of methylamine-borane by considering their activity and durability performances. They achieve releasing of 3.0 equivalent of H-2 via methylamine-borane hydrolysis at room temperature (initial TOF = 297 mol H-2/mol metal x h). Along with activity the catalytic durability of Co/Al2O3 was also studied by carrying out recyclability tests and it was found that these supported cobalt nanoparticles have good durability during the course of the catalytic recycles so that Co/Al2O3 preserves almost its innate activity at 5th catalytic recycle. The studies presented here also contains kinetic investigation of Co/Al2O3 catalyzed methylamine borane hydrolysis depending on the temperature, cobalt and methylamine borane concentrations, which were used to define rate expression and the activation energy of the catalytic reaction. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.