Browsing by Author "Yurtcan, Ayse Bayrakceken"

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Development of Effective Catalysts for Hydrogen Generation from Sodium Borohydride: Ru, Pt, Pd Nanoparticles Supported on Co3O4
(Pergamon-Elsevier Science Ltd, 2019) Bozkurt, Gamze; Ozer, Abdulkadir; Yurtcan, Ayse Bayrakceken
In this study, Ru, Pt, Pd-based catalysts supported on Co3O4 with microwave irradiation-polyol method is used for the hydrogen generation from NaBH4 hydrolysis. Surface morphology and structural properties of the catalysts were studied by using X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS) and inductivity coupled plasma-mass spectrometer (ICP/MS). In addition to, an on-demand hydrogen generation system, which can produce hydrogen from NaBH4 solution and in order to determine the activity of the prepared catalysts, is designed by our group. The effects of solution temperature, amount of catalyst and the initial concentrations of NaBH4/NaOH on the hydrogen generation rate are investigated. The highest hydrogen generation rate at 25 degrees C is obtained from Ru-Co3O4 catalyst with 6514 ml/g(cat).min. In addition, the highest hydrogen generation rate from hydrolysis of NaBH4 with Pt-Co3O4 catalyst is achieved at 55 degrees C as 23916 ml/g(cat).min. The Ea values were calculated as 28.26 kj mol(-1), 43.52 kj mol(-1) and 65.82 kj mol(-1) for Ru-Co3O4, Pt-Co3O4 and Pd-Co3O4, respectively. Furthermore, it is observed that the increase in solution temperature had a very positive effect on the hydrogen generation rate of Pd based catalyst. (C) 2019 Elsevier Ltd. All rights reserved.
Electrical Investigation of Al/PEDOT Structure
(Elsevier Science Bv, 2019) Kaya, Fikriye Seyma; Ozer, Tuba Oznuluer; Turgut, Guven; Yurtcan, Ayse Bayrakceken; Duman, Songul
In this investigation, Al/PEDOT/C/p-Si structure has been fabricated by synthesizing PEDOT/C composites on the p-Si substrate. The thickness and surface morphology of PEDOT/C on p-Si have been investigated by using the scanning electron microscope. The optical characterization of PEDOT/C solution indicated a strong optical absorbance peak located at 267 nm. The electrical characterization of Al/PEDOT/C/p-Si structure was made under dark and illumination conditions at the room temperature. The ideality factor, and barrier height were identified to be 1.28, 1.12 and 0.80 eV, 0.83 eV from current-voltage (I-V) measurements for dark and illuminated conditions, respectively. The results show that the Al/PEDOT/C/p-Si structure may be utilized to be a photodiode in optoelectronic implementations.
Hydrogen Generation from Sodium Borohydride with Ni and Co Based Catalysts Supported on Co3o4
(Pergamon-Elsevier Science Ltd, 2018) Bozkurt, Gamze; Ozer, Abdulkadir; Yurtcan, Ayse Bayrakceken
Hydrogen is an alternative and clean energy carrier, but there are still some production related problems. In this aspect, it is crucial to efficiently generate hydrogen from hydrogen rich materials such as sodium borohydride. In this study, Co3O4 supported Ni and Co catalysts are synthesized via microwave irradiation technique for hydrogen generation from sodium borohydride. In this context, firstly, Co3O4 support material is synthesized by chemical method. Then, Ni and Co catalysts are decorated onto Co3O4 support material by microwave irradiation-polyol method. Prepared catalysts and support material are characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and inductively coupled plasma-mass spectrometer (ICP/MS). A new system is designed by our group in order to determine the activity of the prepared catalysts for hydrogen generation. The effects of different initial NaOH concentrations on hydrogen generation rate are investigated. It is observed that the rate of hydrogen generation increased with an increase in initial NaOH concentration. Co-Co3O4 catalyst at 10% NaOH initial concentration shows the highest hydrogen generation rate as 2823 ml/g(cat).min. In summary, Co-based catalysts are exhibited more activity than Ni-based catalysts in terms of hydrogen generation. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.