Publications Internationales

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    A comparative study of Fm-3m TiO2, ZrO2, HfO2, and CeO2 via atomistic modeling
    (Institute of Materials and Machine Mechanics, Slovak Academy of Sciences, 2025) Mebtouche, Farouk; Abaidia, Saddik Elhak; Messaid, Bachireddine; Lamri, Younes; Nehaoua, Nadia
    Metal oxides (XO2) have been extensively studied experimentally and theoretically. However, atomistic insights into systems like ZrO2 and CeO2, critical in nanocatalysis, remain incomplete. Using ab initio density functional theory (DFT) with the FP-LAPW method in the Wien2k framework and the PBE exchange-correlation functional, we examined the physical and chemical properties of cubic Fm-3m oxides (XO2, X = Ti, Zr, Hf, Ce). Lattice parameters increase with atomic mass except for HfO2, which deviates due to stronger ionic bonding. ZrO2 is the stiffest, followed by HfO2, TiO2, and CeO2. Electronic analysis shows TiO2’s narrow band gap (1.15 eV), ZrO2 and HfO2’s wide gaps (3.16 and 3.77 eV), and CeO2’s moderate gap (2.17 eV) with redox activity. PDOS analysis highlights O 2p and metal d-/f-orbital interactions. These results emphasize distinct properties influencing their applications in photocatalysis, dielectrics, and catalysis, warranting further exploration
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    Excellent Thermoelectric Performance in KBaTh (Th = Sb, Bi) Based Half-Heusler Compounds and Design of Actuator for Efficient and Sustainable Energy Harvesting Applications
    (MDPI, 2023) Debidatta, Behera; Boumaza, Akila; Amraoui, Rabie; Kadri, Salim; Mukherjee, Sanat Kumar; M. Salah, Mostafa; Saeed, Ahmed
    To examine the structural, optoelectronic, thermodynamic, and thermoelectric properties of KBaTh (Th = Sb, Bi) half-Heuslers, we used the full potential, linearized augmented plane wave (FP_LAPW) approach as in the Wien2K simulator. Generalized gradient approximation (GGA), technique, was used for the structural optimization. Mechanical stability and ductility were inherent characteristics of the studied KBaTh (Th = Sb, Bi). Having band gaps of 1.31 eV and 1.20 eV for the KBaTh (Th = Sb, Bi) compounds, they have a semiconducting character. The KBaTh (Th = Sb, Bi) compounds are suggested for use in optoelectronic devices based on studies of their optical characteristics. Thermoelectric properties were investigated using the Boltzmann transport provided by the BoltzTraP software. Since the acquired figures of merit (ZT) values for the KBaTh (Th = Sb, Bi) compounds are all almost equal to one at room temperature, this demonstrates that these substances can be used in thermoelectric devices. Additionally, we used the Slack method to determine the lattice thermal conductivity of KBaTh (Th = Sb, Bi). Our research shows that the half-Heusler compounds under investigation increase actuator response time and hence can be considered as good materials for actuators.
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    Radiation damage induced by reactor neutrons in nano-anatase TiO2 thin film
    (Elsevier, 2020) Hazem, Rafik; Izerrouken, Mahmoud
    Reactor neutrons damage induced in nanocrystalline anatase TiO2 thin film, deposited by sol-gel on silicon substrate, was investigated by grazing angle X-ray diffraction (GAXRD), Raman spectroscopy, four-point probe and UV–visible spectrophotometry. After irradiation, the crystallinity of TiO2 films improves and the electrical resistivity increases, due to an annealing effect associated with the reduction in oxygen vacancies in material. The observed change in the response of irradiated material at higher fluence, demonstrated by a slight reduction in the degree of crystallinity and electrical resistivity, testifies to the simultaneous presence of an annealing effect and a damaging effect during neutron irradiation. Moreover, the difference in the response of anatase and rutile phases of TiO2 under neutron irradiation is explained by the difference in their crystalline structures and kinetic properties of defects. The optical band gap remains unchanged after irradiation meaning that no energy level has been produced within the forbidden region