Browsing by Author "Döner, Ali"

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Citation - WoS: 33
Citation - Scopus: 37
Corrosion behavior of mild steel in 1 M HCl with Cyclotrichium niveum as a green inhibitor
(Elsevier, 2024) Yıldız, Reşit; Arslanhan, Selim; Döner, Ali; Baran, Mehmet Fırat; Yıldız, Reşit; Baran, Mehmet Fırat; Department of Nutrition and Dietetics/ Beslenme ve Diyetetik Bölümü; Department of Medical Services and Techniques / Tıbbi Hizmetler ve Teknikleri Bölümü
Recently, green inhibitors are replacing classical inhibitors in the acid cleaning industry due to very low cost, environmentally friendly and none toxic. In this study, Cyclotrichium niveum is used as a potential green corrosion inhibitor to investigate the corrosion behavior of mild steel (MS) in chloride solution using electrochemical, morphological, structural and quantum chemical methods. Fifty-three flavonoids are detected in methanol extract of cyclotrichium niveum by LC/ESI-MS/MS. While icorr values decreased, Rp and inhibition efficiencies values derived from electrochemical impedance spectroscopy (EIS) and linear polarization resistance (LPR) increased in increasing inhibitor concentrations. Maximum inhibition efficiency is found to be 97.3%, that is the almost highest value, when compared to previous studies and plant extract is classified as a mixed type inhibitor with respect to the potentiodynamic polarization (PDP). The model that best fits the experimental values is the Langmuir isotherm. The temperature effect is also studied in the range of 25–55 ○C. Higher activation energy is obtained in the presence of inhibitor, suggesting that it acts as an efficient inhibitor by forming a physical barrier to the charge and mass transfer reaction, leading to reduction in corrosion rate. Scanning electron and atomic force microscopies showed the more uniform, crack and pits free structure, confirming that there is a protective film over the MS surface for inhibited solution. XPS analysis showed the existence of C, O, and Fe atoms on the MS surface. Quantum chemical calculation manifested the adsorption mechanism associated with the electronic structure of the molecules. The findings of this work can be applicable in chemical cleaning process with acid treatment.
Citation - WoS: 11
Citation - Scopus: 14
Electrocatalysis property of CuZn electrode with Pt and Ru decoration
(International Journal of Hydrogen Energy, 2021) Toprak Döşlü, Serap; Döner, Ali; Yıldız, Reşit; Yıldız, Reşit; Toprak Döşlü, Serap; Department of Nutrition and Dietetics/ Beslenme ve Diyetetik Bölümü
Electrocatalysis properties strongly depend on the interaction of metallic particles and this interaction enables to change the electronic structure of alloys which enhances the catalytic activity. This property is the key factor in the developing of cost-effective and efficient Hydrogen Evolution Reaction (HER) electrocatalysts for sustainable hydrogen production. In this study, novel electrocatalysts which are decorated with Pt and Ru have been developed for HER electrocatalysis. Microscopic analysis such as scanning electron microscopy (SEM), energy dispersive X-ray (EDX), X-ray diffraction (XRD) and atomic force microscopy (AFM) are performed to determine the morphological and compositional structures. Electrocatalysis properties are evaluated by cathodic current-potential curves, electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) in 1.0 M KOH solution. Chronoamperometry (CA) and cycle tests are used for stability/durability of electrocatalysts. Results show that a small onset potential of the porous Cu/Ni/CuZn–Pt is obtained for HER. Exchange current density and polarization resistance are found to be 5.39 mA cm−2 and 2.0 Ω cm2 at overpotential of −100 mV for porous Cu/Ni/CuZn–Pt, respectively, indicating that Cu/Ni/CuZn–Pt is higher electrocatalytic properties than the others. Moreover, very low overpotentials at 10 and 40 mA cm−2 are obtained on porous Cu/Ni/CuZn–Pt compared with porous Cu/Ni/CuZn–Ru and Cu/Ni/CuZn. Porous Cu/Ni/CuZn–Pt also displays excellent stability/durability in test solution. The remarkable electrocatalysis properties of porous Cu/Ni/CuZn–Pt can be explained due to high porous structure, leaching of Zn from the deposit, intrinsic activity of Pt as well as changing in the electronic structure. It should be considered that porous Cu/Ni/CuZn–Pt is of high corrosion resistance in test solution for 120 h, which makes it good candidate for HER.
Citation - WoS: 15
Citation - Scopus: 18
Experimental and theoretical investigation of adsorption and inhibition properties of 2-Amino-1,3,5-triazine-4,6-dithiol against corrosion in hydrochloric acid solution on mild steel
(Elsevier, 2023) Arslanhan, Selim; Yıldız, Reşit; Döner, Ali; Yıldız, Reşit; Department of Nutrition and Dietetics/ Beslenme ve Diyetetik Bölümü
In this work, 2-Amino-1,3,5-triazine-4,6-dithiol (2-ATD) as novel and high efficiency corrosion inhibitor has been investigated for mild steel (MS) corrosion in 0.5 M HCl solution using electrochemical methods, scanning electron microscopy (SEM), energy disperse X-ray spectroscopy (EDX), atomic force microscopy (AFM) and quantum chemical calculation methods. Potentiodynamic polarization (PDP) curves indicate that 2-ATD is mixed type inhibitor, corrosion inhibition efficiency increased with increasing inhibitor concentration and reached its value of 96.5%. Evolution of exposure time versus corrosion behavior of 2-ATD is examined in corrosive medium. While corrosion potential (Ecorr) shifted more negative values, polarization resistances (Rp) decreased after 120 h exposure time due to the corrosion process. H2 volume is measured in uninhibited and inhibited solutions (10 mM 2-ATD) after 120 h exposure time. Very low volume (3.6 mL cm-2) of H2 is obtained on MS electrode in inhibited solution after 120 h of exposure, indicating that 2-ATD covers the entire surface against aggressive attack and retards the both anodic dissolution of MS and cathodic hydrogen evolution reactions. The adsorption process proposal is the Langmuir isotherm which is most suitable. Adsorption and thermodynamic parameters show that 2-ATD has a strong adsorption effect onto MS surface and includes mixed adsorption style (physical and chemical). Corrosion current density increases with increasing temperature and high activation energy (Ea) proves the strong adsorption of 2-ATD on the MS surface. Anti-corrosion mechanism of 2-ATD is described more detail with the potential of zero charge method. SEM, EDX and AFM analysis support the obtained results of electrochemical methods and confirm the existence of protective layer and strong adsorption of 2-ATD on the MS surface. Chronoamperometry test shows that current densities are almost constant whole experiment in the presence of organic film. Finally, quantum chemical calculation method of 2-ATD in blank solution is performed to investigate the active sites for possible attachment with MS surface.
Citation - WoS: 3
Citation - Scopus: 5
A study for hydrogen evolution on Pt–MnCu electrocatalyst
(Elsevier, 2023) Yıldız, Reşit; Arslanhan, Selim; Döner, Ali; Yıldız, Reşit; Department of Nutrition and Dietetics/ Beslenme ve Diyetetik Bölümü
Electrocatalysts to be used in electrolysis, which is one of the hydrogen production methods, are very important. The development of electrocatalysts is related to the internal structure of combinated more than one metal. In the present work, the graphite substrate is coated with manganez (C/Mn), manganez-copper (C/MnCu) and this surface is modified with platinum nanoparticles (C/MnCu–Pt) using the electrodeposition method. Prepared electrocatalysts are used for characterization, hydrogen evolution reaction (HER) and stability using cyclic voltammetry (CV), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), X-ray diffraction (XRD), cathodic current-potential curves, electrochemical impedance spectroscopy (EIS) and chronoamperometry (CA). Hydrogen gas is measured in a basic environment by establishing an experimental electrolysis setup on these electrocatalysts. Results showed that binary MnCu enhances the characteristic current density of Tafel curves, reduces the polarization resistance and enhances the hydrogen gas volume compared to graphite substrate and single Mn coating. Apart from that, much more effective results are obtained on the C/MnCu–Pt electrocatalyst. Namely, a very high exchange current density (io = 5.50 mA cm−2), a very low polarization resistance (3.2 Ω cm2) and a very low overpotential (50 mV) at 10 mA cm−2 are obtained on the C/MnCu–Pt electrocatalyst. In addition to high performance, C/MnCu–Pt electrocatalyst exhibits good stability in alkaline medium.