Browsing by Author "Najri, Bassam A."

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Activity and Structure Analysis of Highly Functional Ru-Pt-Ni/AC Nanocatalysts for Efficient Glucose Electrooxidation
(Springer, 2025) Ulas, Berdan; Yilmaz, Yonca; Demir Kivrak, Hilal; Najri, Bassam A.; Erunal, Ebru
A promising Ru-Pt-Ni/AC catalyst for direct glucose fuel cells was developed via the supercritical carbon dioxide deposition method which enabled a uniform distribution of metals, with an average particle size of 3.85 nm. The electrocatalytic activity and stability of the nanocatalysts for glucose electrooxidation were evaluated using chronoamperometry (CA), electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV) in alkaline media. Under these conditions, the catalyst exhibited a notably high specific activity of 3.98 mAcm(-)(2) for glucose electrooxidation, significantly surpassing the performance of conventional catalysts. Electrochemical impedance spectroscopy further confirmed the kinetic improvement, showing a clear reduction in charge transfer resistance with increasing potential. Complementary DFT calculations supported the experimental findings by evidencing modifications in surface electrophilicity and their role in activity enhancement.
Bimetallic Ruthenium-Cobalt Catalyst Supported on Carbon Nanotubes: Synthesis, Characterization, and Application in Electrochemical Sensing of Isoleucine
(Wiley, 2025) Arici, Omruye Ozok; Caglar, Aykut; Najri, Bassam A.; Aktas, Nahit; Kivrak, Arif; Kivrak, Hilal
In this work, a bimetallic Ru-Co catalyst based on carbon nanotubes (Ru-Co/CNT) with a Ru to Co ratio of 95:5 is developed. The catalyst, featuring a total metal loading of 3% on the CNTs, is synthesized using the NaBH4 reduction method. Several analytical analyses are used to detect the properties of the Ru-Co/CNT catalyst. X-ray diffraction (XRD) provides information on crystal structures of the catalysts, high-resolution transmission electron microscopy (HR-TEM) reveals particle size and distribution, inductively coupled plasma mass spectrometry (ICP-MS) measures the elemental composition, and X-ray photoelectron spectroscopy (XPS) use to investigate the chemical oxidation states. In addition, thermal techniques including temperature-programmed reduction (TPR), temperature-programmed oxidation (TPO), and temperature-programmed desorption (TPD) are used to recognize the active sites on the catalyst's surface and the acidity. Then, the Ru-Co/CNT catalyst is applied as a sensor for isoleucine amino acid for the first time. It shows high performance with these parameters, sensitivity (0.002 mA cm-2 mm), LOD - limit of detection (0.04 mu m), and LOQ - limit of quantification (0.12 mu m). Moreover, the interferences of common serum blood including (D-glucose, uric acid, ascorbic acid, and L-tryptophan) are studied. The findings indicated that the sensor is applicable to work in complex biological systems.