Zakir, O.; Guler, O.; Idouhli, R.; Aklalouch, M.; Dikici, B.; Khadiri, M.E.; Abouelfida, A.; Selen, V.; Şimşek, T.

In this study, the photocatalytic performance of NbTiZrW-based high-entropy alloys (HEAs) with Hf, Mo, and Ta additions was investigated. The alloys were synthesized by mechanical alloying for 120 h under a high-purity Ar atmosphere to prevent oxidation. The photocatalytic activity of the samples was evaluated based on the degradation of methylene blue (MB) under UV irradiation. Structural and chemical characterizations were performed using energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The results showed that MB removal by adsorption reached 22.96 % for NbTiZrWHf, 21.90 % for NbTiZrWTa, and 47.01 % for NbTiZrWMo. The incorporation of Mo into the NbTiZrW alloy was found to enhance electrostatic interactions between MB molecules and the alloy surface. Upon UV irradiation, the degradation efficiency increased significantly, reaching 32.84 % for NbTiZrWHf, 82.02 % for NbTiZrWTa, and 46.13 % for NbTiZrWMo within 3 h. The improved performance of the NbTiZrWHf alloy was attributed to its low particle size, which provided a larger number of active sites for photocatalytic activity, as confirmed by SEM analysis.

AtıfScopus1·OpenAlex1

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Sakar, E.; Guler, O.; Alim, B.; Guler, S.H.; Dikici, B.; Lampke, T.

This study presents the production and comprehensive assessment of a Refractory High Entropy Alloy (RHEA) with a ZrNbTaMoW composition for possible usage nuclear reactor applications. The alloy was synthesized using the mechanical alloying (MA) method, and its radiation properties were examined. Elemental powders of Zr, Nb, Ta, Mo, and W were utilized in equimolar quantities during the 120-hour MA process, conducted under a high-purity Ar atmosphere to prevent oxidation. The obtained HEA was then subjected to a mechano-thermal process to transform it into Refractory High-Entropy Oxide (RHEO) for comparing their radiation-shielding performance under oxide conditions. The characterization of the produced alloys through X-ray diffraction (XRD), scanning electron microscopy (SEM), and electron dispersive spectroscopy (EDS). The photon shielding parameters of the alloys were experimentally obtained for various energies emitted from a 133Ba radioactive source, employing a Canberra UltraLEGe semiconductor detector. Furthermore, theoretical calculations were performed to validate the experimental data and to evaluate the alloys' photon shielding capabilities comprehensively. For this purpose, Phy-X/PSD software was employed to determine mass attenuation coefficients, half-value layer, effective atomic number, and effective electron density. Fast neutron absorption capabilities were determined through the calculation of average absorption cross-sections in the 2–12 MeV energy range. The results showed that the oxidation process significantly diminished the photon absorption capacity of RHEA.

AtıfScopus34·OpenAlex37

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Zakir, O.; Guler, O.; Idouhli, R.; Nayad, A.; Khadiri, M.E.; Guler, S.H.; Abouelfida, A.; Dikici, B.

The photocatalytic performance of high entropy alloy (HEA) and its oxide form (high entropy oxide, HEO) have been evaluated in this study. The HEA, composed of Nb, Ta, Zr, Mo, and W powders, was synthesized through a mechanical alloying process for 120 h. This process was carried out under a high-purity Ar atmosphere to prevent oxidation. Subsequently, the HEA was converted into HEO via a mechano-thermal oxidation method 900 °C for 12 h. The photocatalytic activity of both oxidized and non-oxidized samples was systematically evaluated by degradation of methyl blue (MB) under UV irradiation. Electron dispersive spectroscopy (EDS), X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) were used to investigate the structural and chemical features of the alloys. Furthermore, BET surface area analysis and Zeta potential measurements were conducted to understand the alloys’ surface properties and stability in aqueous solutions. The results showed that the HEA has a remarkable photodegradation performance of around 58.77% which is two times higher than that observed with the HEO. Graphical abstract: (Figure presented.)

AtıfScopus31·WoS30·OpenAlex28

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