JOURNAL OF MATERIALS AND ELECTRONIC DEVICES

Cu-doped TiO2 catalysts for catalytic hydrogenation/degradation of organic compounds in water

Rüştü Deniz Çelebi — 2024-03-11

In this study, CuCl₂ was attached to TiO₂ support material using two different methods, yielding two new catalysts. To analyze the catalysts' structural and morphological properties, various techniques were used, including Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. The catalytic activity of the prepared catalysts was tested for the catalytic degradation reactions of 2-nitroaniline, 4-nitroaniline, 4-nitrophenol, and eosin yellow compounds in the presence of NaBH₄ in an aqueous solution. It was discovered that the prepared materials are extremely active catalysts. The degradation reactions were efficient, and the catalysts showed excellent selectivity for the organic compounds. These findings suggest that the structural and morphological properties of the prepared catalysts play an important role in increasing their catalytic activity. The catalysts' high activity can be attributed to their pore size distribution, and surface chemistry.

Structural and Electrochemical Insights into Pt65Cu35 Alloy for Enhanced HER Performance

Mustafa Zeki Kurt* — 2024-03-11

This study presents a comprehensive structural and electrochemical characterization of Pt₆₅Cu₃₅ alloy nanoparticles (NPs) for their application in the hydrogen evolution reaction (HER). X-ray diffraction method have been used to determine structural properties and revealed a well-defined crystal structure corresponding to the face-centered-cubic (fcc) Pt₃Cu₁ alloy phase, evidenced by characteristic Miller indices as the (111), (200), (220), (311), and (222) planes. Further examination yielded a uniform lattice constants of 3.923 Å, indicating a homogeneous crystal lattice. Assessment of crystallite size, 2.9 nm, and microstrain, 3.85%, underscored the influence of PtCu alloy formation on structural defects and grain boundaries within the NPs. The stoichiometric calculation via energy-dispersive X-ray spectroscopy confirmed Pt and Cu ratio with a percentage of 65 and 35 in the structure and scanning electron microscope showed a spherical morphology attributed to the influence of polyvinylpyrrolidone molecules during synthesis. Moreover, electrochemical investigations revealed promising HER catalytic performance, with cyclic voltammetry (CV) analyses demonstrating Pt-H formation followed by H₂ gas formation. Linear sweep voltammetry (LSV) analysis confirmed a maximum current density of 1.52 mA cm^-2 was achieved at -0.37 V, indicating high catalytic activity. Furthermore, CV curves recorded over 500 cycles elucidated cyclic behavior, with a current density of 3.04 mA cm^-2 gradually decreasing over subsequent cycles before stabilizing beyond the 100th cycle. These findings underscore the exceptional electrocatalytic performance of Pt₆₅Cu₃₅ catalysts, highlighting their potential for various electrochemical applications. Further research avenues may focus on elucidating underlying mechanisms governing cyclic behavior to optimize catalyst design for enhanced performance and durability.

Extrusion die design and production from Inconel 718 superalloy material

Rabia KIRKGEÇİT* — 2024-03-11

In this study, extrusion mold design and manufacturing were examined using Inconel 718 superalloy material to address critical issues in the production process. The aim was to prevent production disruptions caused by thermal fatigue, hot tearing, thermal shock, abrasion, and other mechanical deformations. The use of a material with advanced mechanical properties was targeted for this purpose. Inconel 718 and hot work tool steel were compared, evaluating chemical composition, surface roughness, and conductivity. It was concluded that Inconel 718, with its higher Cr content, superior mechanical properties, and similar conductivity values, provides advantages in the production process.

A Brief Overview for Fundamental Electrical Characterization Techniques for Thin Films and Nanostructures

Erdal KARAKUŞ — 2024-03-11

Thin films and nano materials are crucial for the advancement of technology and industrial applications. Electrical characterization of such materials is crucial for understanding the internal characteristics of the materials and to produced advanced and innovative materials. Thin films are special materials which were applied as a layer on a certain surface. Such films were often applied in nanoscale and therefore, they were associated with nanotechnology and nanomaterials. Thin films were used in electronical devices, solar cells, sensors, solar harvesting devices, detector technologies, etc. Electrical characterization of thin films and nanostructures enables researchers to investigate different properties such as impedance, resistance, capacitance under various conditions such as temperature, frequency, voltage, etc. Materials in desired electrical properties could be developed. Similarly, nanomaterials also exhibit unique characteristics where electrical characterization techniques has important role for understanding the intrinsic properties the materials. Nanomaterials such as carbon nanotubes, graphene, and metal nanoparticles exhibit outstanding electrical and electronical characteristics. Electrical characterization of such materials may find applications in energy storage applications, biomedical applications etc. In this report, we briefly discussed electrical characterization methods used for thin films and nanomaterials such as Hall Effect, Four Point Probe Technique, Van der Pauw Technique, Capacitance – Voltage (C-V) Measurements, Electrical Impedance Spectroscopy.

The Effect of Different Approach Methods on the Mechanical Properties of CuNi12Zn24 Material Production

Rabia KIRKGEÇİT* — 2024-03-11

Bu araştırma çalışması, iki farklı proses kullanılarak üretilen CuNi12Zn24 malzemesinin mekanik özelliklerinin incelenmesini amaçlamıştır. Her iki prosesin de malzemenin sertlik, çekme mukavemeti, akma mukavemeti ve elektrik iletkenliği gibi temel mekanik özellikleri üzerindeki etkisi değerlendirildi. İlk işlem, döküm çıktı numunelerinin 9 mm'den 2 mm kalınlığa kadar soğuk haddelemeye tabi tutulmasını içeriyordu. Haddeleme işleminden sonra yapılan mekanik testler, malzemenin 227 HV sertliğe, 625,10 MPa çekme mukavemetine ve 618,69 MPa akma mukavemetine sahip olduğunu gösterdi. Ek olarak malzeme %7,9 IACS değeriyle iyi iletkenlik sergiledi. İkinci işlem, numunelerin 750°C'de 2 saat süreyle tavlanmasını, ardından su verme ve ardından 2 mm kalınlığa kadar soğuk haddelemeyi içeriyordu. Bu işlemden elde edilen numunelerin sertlik değeri 226 HV, çekme mukavemeti 527,50 MPa, akma mukavemeti ise 526,18 MPa olmuştur. İletkenlik değeri %8,8 IACS olarak belirlendi.

Karşılaştırmalı analiz, tavlamaya tabi tutulan numunelerin mekanik test değerlerinin daha olumlu olduğunu ortaya çıkardı. İki proses arasındaki mekanik özelliklerdeki küçük fark, CuNi12Zn24 malzemesinin üretiminde her iki metodun da uygulanabilir olduğunu göstermektedir.