Browsing by Author "Karataş, Y."

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Carbon-Based Nanostructures and Nanomaterials
(Elsevier, 2020) Karaca, B.; Karataş, Y.; Cakar, A.B.; Gülcan, M.; Şen, F.
Carbon has been used in many different ways throughout history, including human life and technology. Since ancient times, coal, carbon black, and graphite have been used for writing and drawing. Recently, conjugated carbon nanomaterials especially carbon nanotubes and fullerenes have been used as a material to store energy due to its unique properties. In the last 10years, nanostructures and nanomaterials have taken attentions extensively due to having many advantages including excellent mechanical, thermal, chemical, and electrical. Therefore, carbon-based nanostructures and nanomaterials nowadays found the opportunity to be applied in numerous areas such as electronics, sensors, composite materials, drug delivery, energy conversion and storage, and field emission devices. In the 21st century, the capacity of these materials and the impressive aspects as environmentally safe and green fabrication processes and industrial production of carbon-based nanostructures and nanomaterials are extremely necessary, and therefore, it can be defined as the primary research field for technological and scientific applications. This section provides a broad overview of the fundamental properties of carbon-based nanostructures and nanomaterials, simple synthesis methods and a wide range of technological and industrial applications. © 2021 Elsevier Inc. All rights reserved.
CuO Supported Ru Nanoclusters: A Highly Efficient Nanocatalyst for the Hydrolytic Dehydrogenation of Morpholine Borane
(Elsevier B.V., 2025) Rüzgar, A.; Karataş, Y.
In this study, the development of a new, efficient and economical hydrogen production system was aimed and for this purpose, ruthenium(0) nanoparticles placed on copper(II) oxide (CuO) support were synthesised as catalysts. The catalyst was thoroughly characterized by various advanced techniques including Transmission Electron Microscopy (TEM), TEM coupled with Energy Dispersive X-ray Spectroscopy (TEM-EDX), Scanning Electron Microscopy (SEM), SEM-EDX, SEM mapping, X-ray Photoelectron Spectroscopy (XPS), and X-ray Diffraction (XRD). According to the TEM analysis, the Ru(0) nanoparticles were well-dispersed on the CuO support with an average particle size of approximately 2.24 nm. The catalyst synthesised by a feasible and efficient method showed extremely high efficiency in hydrogen gas production as a result of hydrolysis of morpholine-borane (MB) complex. By interpreting the data obtained as a result of the experimental studies, the TOF value in hydrolysis reactions using Ru(0)/CuO catalyst was calculated as 44.37 min⁻¹. This value stands out as the highest catalytic activity achieved compared to similar systems reported so far in the literature. A series of kinetic studies on the catalytic hydrolysis of MB were conducted by varying the amount of catalyst/substrate and temperature and the rate law expression and activation parameters were generated by collecting the kinetic data. The apparent activation energy (Ea), activation enthalpy (ΔH‡) and activation entropy (ΔS‡) of MB hydrolysis catalyzed by Ru@CuO were calculated as 56.49 kJ mol⁻¹, 54.04 kJ mol⁻¹ and −40.07 J (mol × K)⁻¹, respectively. © 2025 Elsevier B.V.
Magnetic Nanoparticles
(Elsevier, 2020) Acidereli, H.; Karataş, Y.; Burhan, H.; Gülcan, M.; Şen, F.
Magnetic nanoparticles (MNPs) have widespread attention because of their unique features. For a few decades, growing development in chemical synthesis of nanomaterials and material surface modification have been seen and performed in numerous applications including biomedicine, biotechnology, catalysis, magnetic chemistry thermoelectric materials, etc. Various methods for fabrication of MNPs which have a controllable size, distribution, and surface modification have been reported. In these methods, several techniques containing irradiation, microwave, ultrasonication, vapor deposition, electrochemical, and microwave are applied to produce MNPs either in bottom-up or top-down processes. Generally, magnetic synthesis of nanoparticles is carried out by using these two processes. Nanomaterials with magnetic properties have wide applications in many fields such as biology, medicine, and engineering. In this section, the recent developments in the structures, occurrences, most commonly used samples, and common areas of use of the MNPs are given. © 2021 Elsevier Inc. All rights reserved.
Synthesis, Characterization, and Determination of the Catalytic Roles of Tungsten (VI) Oxide-Supported Pd (0) Nanoparticles in the Reduction of Nitroaromatic Pollutants
(Elsevier Ltd, 2025) Rüzgar, A.; Karataş, Y.; Yurderi, M.; Şener, L.; Gülcan, M.; Zahmakiran, M.
One of the most important approaches for industrial and environmental catalytic applications is to develop a promising, simple, and effective method. Toxic organic pollutants in wastewater, such as nitroaromatic contaminants, have become a global issue, threatening aquatic life and obstructing essential elements required for the survival of living organisms. In this study, a palladium pre-catalyst supported on tungsten (VI) oxide (Pd2+/WO3) was prepared with a 2 % metal loading using a simple and conventional wet impregnation method. The efficiency of this pre-catalyst was investigated for the reduction of nitroaromatic pollutants (2-nitrophenol (2-NP), 4-nitrophenol (4-NP), and 2,4-dinitrophenol (2,4-DNP)) into their corresponding aminophenol compounds in the presence of an excess amount of NaBH4 as the reducing agent. Characterization techniques such as ICP-OES, XRD, SEM, SEM/EDX, TEM, and XPS analysis revealed that Pd (0) nanoparticles were well-dispersed on the WO3 support, with an average particle size of 2.2 ± 0.1 nm. The catalytic activities of Pd (0) nanoparticles for the reduction of nitroaromatic pollutants to aminophenols in the presence of NaBH4 were determined in terms of initial TOF, calculated as 127.2 min−1 for 2-NP, 109.4 min−1 for 4-NP, and 353.1 min−1 for 2,4-DNP. The results demonstrated that the Pd/WO3 nanocatalyst exhibited excellent catalytic efficiency and stability (>85 %) even after five catalytic cycles in the reduction of nitroaromatic pollutants. Considering both the simple preparation process and the effective catalytic reduction of nitroaromatic pollutants, this study presents a great opportunity for the practical application of the Pd/WO3 nanocatalyst in wastewater treatment. © 2025 Elsevier B.V.