Browsing by Author "Onses, M. Serdar"

Now showing 1 - 9 of 9

Open Access
The effects of stage house coupling on multipurpose auditorium acoustics
(Elsevier, 2022-03-01) Peçenek, H.; Yetiman, S.; Kılıç Dokan, F.; Onses, M. Serdar; Yılmaz, E.; Sahmetlioglu, E.
Nitrogen-doped composites have the potential to achieve well electrochemical performance by enabling convenient contact of the electrolyte ions for carbon-based materials. A good combination of metal oxide and carbonaceous material is a critical challenge in the development of composites. Herein, we demonstrate a highly capacitive and superior cycle performance of MnO2 based supercapacitor electrodes. The addition of different forms of carbon nanomaterials (carbon nanotube and graphene) and MXene is particularly studied. MnO2 based composite materials are capable of capacitance retention over 95%, with high specific capacitance compared to pure N-doped MnO2. The highest specific capacitance was achieved with MXene based MnO2 composite, which exhibits 457 Fg-1, at a current density of 1 A g−1 with extreme cycling efficiency (102.5%, after 1000 cycles). High conductivity and large surface area are stimulated by the propitious interaction between MnO2 and nanoscale materials, resulting in superior supercapacitor efficiency. This study highlights the possible potential of carbon-based MnO2 composite electrodes which could be useful for future energy storage applications.
Open Access
From bio-waste to biomaterials: The eggshells of Chinese oak silkworm as templates for SERS-active surfaces
(Elsevier BV, 2021-12-15) Zang, Lian-Sheng; Chen, Yong-Ming; Bilican, Behlül Koç; Bilican, İsmail; Sakir, Menekşe; Wait, James; Çolak, Arzu; Karaduman, Tuğçe; Ceylan, Ahmet; Ali, Asad; Elbüken, Çağlar; Onses, M. Serdar; Kaya, Murat
Although over 80% of the world’s existing animal species are insects, with each of these species having unique eggshell morphologies, limited information is available regarding the use of their eggshells in material science applications. The present research discusses using discarded eggshells of the Chinese oak silkworm (Antheraea pernyi) as a technological material. The 3-dimensional aspects of the insect’s eggshell were examined in detail, demonstrating the complexity of their novel surface morphology. The outer surface of the eggshell was comprised of a hexagonal structure, whereas the inner surface consists of a mostly smooth surface. Distinctive layers of the eggshell were observed when cross sections of the surface were analyzed. The elastic modulus of the inner part of the eggshell is substantially greater than that of the outer part. The physicochemical properties of the eggshell were characterized and no toxic properties were found. The hexagonal structures found on the outer surface of the eggshell provide a highly suitable template for silver nanostructure deposition. The resulting silver decorated surfaces can be used to detect molecules via surface-enhanced Raman scattering (SERS) effects. The deposition of silver renders the surface antimicrobial, whereas the original surface was microbial. Collectively, the insights gained in this study will be key in developing advanced engineering applications of the insect eggshells.
Embargo
Highly compressible binder-free sponge supercapacitor electrode based on flower-like NiO/MnO2/CNT
(Elsevier BV, 2022-08-25) Peçenek, H.; Kılıç Dokan, F.; Onses, M. Serdar; Yılmaz, E.; Sahmetlioglu, E.
The increasing demand for flexible electronics encourages the innovative and functional designs of electrode materials with high performance and compressibility. In this work, we report a compressible supercapacitor electrode which is prepared by coating electrically active NiO/MnO2/carbon nanotube (CNT) composite onto a sponge. A cube of sugar was used as the template to obtain the sponge through infiltration and cross-linking of polydimethylsiloxane (PDMS). NiO/MnO2/CNT was deposited on the PDMS sponge to generate substantial amount of interface, resulting in a specific capacitance of 23 F/g at 0.1 A /g in a three-electrode system and 1.32 F/g at 0.5 mA in a symmetric supercapacitor. The proposed system exhibits excellent cycling stability with capacitance retention over 10.000 cycles. The strong adhesion of the binary metal oxides and carbon material onto the porous nonconductive sponge enables mechanical stability under compression-release cycles. Our study indicates that this electrode is a promising candidate for applications in flexible electronics. Furthermore, this research might guide the development of flexible, high-performance, and low-cost electrodes, which will be useful in wearable energy storage systems.
Open Access
Machine learning-assisted pesticide detection on a flexible surface-enhanced raman scattering substrate prepared by silver nanoparticles
(American Chemical Society, 2022-09-12) Onses, M. Serdar; Ruzi, M.; Ceylan, A.; Sakir, M; Camdal, A.; Celik, N.; Sahin, F.
Access to clean water is a pressing challenge affecting millions of lives and the aquatic body of the Earth. Sensitive detection of pollutants such as pesticides is particularly important to address this challenge. This study reports eco-friendly preparation of the surface-enhanced Raman scattering (SERS) substrate for machine learning-assisted detection of pesticides in water. The proposed SERS platform was prepared on a copy paper by reducing a silver salt using the extract of a natural plant, Cedrus libani. The fabricated SERS platform was characterized in detail using scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The high-density formation of silver nanoparticles with an average diameter of 41 nm on the surface of the paper enabled detection of analytes with a nanomolar level sensitivity. This SERS capability was used to collect Raman signals of four different pesticides in water: myclobutanil, phosmet, thiram, and abamectin. Raman spectra of the pesticides are highly complex, challenging accurate determination of the pesticide type. To overcome this challenge and distinguish pesticides, machine learning (ML) approach was used. The ML-mediated detection of harmful pesticides on a versatile, green, and inexpensive SERS platform appears to be promising for environmental applications.
Open Access
Microwave-assisted fabrication of high-performance supercapacitors based on electrodes composed of cobalt oxide decorated with reduced graphene oxide and carbon dots
(Elsevier, 2022-05) Yetiman, S.; Peçenek, H.; Onses, M. Serdar
This study presents microwave-assisted preparation of cobalt oxide (Co3O4) based nanocomposite electrodes doped with carbon dots and reduced graphene oxide. The calcination of the precursors at 400 °C for 2 h results in nanocomposites. A three-electrode cell in 2M KOH solution is used for the electrochemical measurements. The carbon dot containing electrodes enables the highest specific capacitance of 936 Fg−1 at 0.5 Ag−1 current density. Specific capacitances of pure Co3O4, and Co3O4@RGO electrodes are 448 Fg−1 and 482 Fg−1 at 0.5 Ag−1, with good rate capability even at 10 Ag−1, respectively. The cyclic stability of the electrodes is reasonably high and the electrodes retain 93%, 87%, and 88% of their initial capacitance after 10,000 cycles for Co3O4, Co3O4@RGO, and Co3O4@RGO@CDs, respectively. The optimized Co3O4@RGO@CDs electrodes were used to fabricate a symmetric supercapacitor that exhibits high specific capacitance (126 Fg−1 0.25 Ag−1) and long cycle life (%81 retention after 10,000 cycles). The fabricated supercapacitor has energy density of 17.5 Wh kg−1 and power density of 2522 W kg−1. The outstanding results demonstrate the promise of carbon dots doped transition metal oxides-based nanoparticles as promising electrodes for supercapacitor applications.
Open Access
Outstanding supercapacitor performance with intertwined flower-like NiO/MnO2/CNT electrodes
(Elsevier Ltd, 2022-01-11) Peçenek, H.; Kılıç Dokan, F.; Onses, M. Serdar; Yılmaz, E.; Sahmetlioglu, E.
Binary metal oxides have been broadly investigated as a new electrode material for supercapacitor applications owing to their high reversible performance and good conductivity. When compared to a single candidate, the composite's electrochemical performance is considerably improved by the unique mix of pseudo-material and carbon material. Herein, we report a facile and rational synthesis procedure to fabricate a high performance supercapacitor electrode. The prepared NiO/MnO2/ carbon nanotube (CNT) composite has wonderfully stratified flower-like morphology. The positive synergism among components and unique structure has enabled a high specific capacitance of 1320 F/g at 1 A g−1. After 3000 cycles, the supercapacitor maintains more than 90% of its initial capacitance. Moreover, we also successfully prepared a symmetrical supercapacitor which is made up of two pieces of composite electrode separated with a membrane. The findings highlight that NiO/MnO2/CNT composite is highly desirable for future hybrid energy storage applications.
Open Access
Scalable fabrication of MXene-PVDF nanocomposite triboelectric fibers via thermal drawing
(2022-12) Hasan, Md Mehdi; Sadeque, Md Sazid Bin; Albasar, Ilgın; Pecenek, H.; Dokan, F. K.; Onses, M. Serdar; Ordu, Mustafa
In the data-driven world, textile is a valuable resource for improving the quality of life through continuous monitoring of daily activities and physiological signals of humans. Triboelectric nanogenerators (TENG) are an attractive option for self-powered sensor development by coupling energy harvesting and sensing ability. In this study, to the best of the knowledge, scalable fabrication of Ti3C2Tx MXene-embedded polyvinylidene fluoride (PVDF) nanocomposite fiber using a thermal drawing process is presented for the first time. The output open circuit voltage and short circuit current show 53% and 58% improvement, respectively, compared to pristine PVDF fiber. The synergistic interaction between the surface termination groups of MXene and polar PVDF polymer enhances the performance of the fiber. The flexibility of the fiber enables the weaving of fabric TENG devices for large-area applications. The fabric TENG (3 × 2 cm2) demonstrates a power density of 40.8 mW m−2 at the matching load of 8 MΩ by maintaining a stable performance over 12 000 cycles. Moreover, the fabric TENG has shown the capability of energy harvesting by operating a digital clock and a calculator. A distributed self-powered sensor for human activities and walking pattern monitoring are demonstrated with the fabric. © 2022 Wiley-VCH GmbH.
Open Access
Silver nanoflowers with SERS activity and unclonable morphology
(Elsevier, 2023-02-26) Şakir, Menekşe; Torun, Neslihan; Kayacı, Nilgün; Torun, İlker; Kalay, Mustafa; Onses, M. Serdar
This manuscript presents surface-growth of silver nanoflowers with high surface-enhanced Raman scattering (SERS) activity and unique morphology. The nanoflower morphology is mediated by the seed-mediated growth of silver nanostructures over gold nanoparticles immobilized on hemispherical polymer features. Randomly positioned hemispherical polymer features are self-assembled via surface dewetting of a nanoscopic film of poly (2-vinylpyiridine) (P2VP) film on the polystyrene-grafted substrate. The time-dependent growth study shows that the silver nanoflowers evolve from the circular contact lines separating the P2VP features and underlying substrate. The three-dimensional nature of the underlying feature facilitates growth in a flower like morphology. The silver nanoflowers exhibit high levels of SERS activity allowing for detection of rhodamine 6G at a 100 pM level under 532 nm laser excitation. A feature matching algorithm-based image analysis confirms the unique morphology of every single silver nanoflower. The direct fabrication of silver nanoflowers at random positions with unclonable morphology and high SERS activity is particularly promising for anti-counterfeiting applications.
Open Access
Superhydrophobic coatings for food packaging applications: A review
(Elsevier, 2022-06) Ruzi, M.; Celik, N.; Onses, M. Serdar
Food waste is a serious problem in our modern era, causing economic loss and exacerbating issues like hunger, environmental pollution, and water shortage. Residual food is one main culprit that can be easily eliminated by proper packaging. Advanced packaging techniques with self-cleaning and anti-fouling capabilities are critically important to tackle this issue. In this regard, superhydrophobic coatings are emerging as an innovative approach to address many critical issues in the food industry. Superhydrophobic coatings can prevent fouling and contamination of food packages. An additional capability is the minimization of food waste and improving consumer experience due to the easy sliding of food from the inner side of the package. In this article, we provide an overview of recent studies on the application of superhydrophobic coatings and surfaces for food packaging applications, with a focus on studies aimed at reducing residual food waste via superhydrophobic coatings prepared from edible, nontoxic, and ecofriendly materials.