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Article Citation - WoS: 16Citation - Scopus: 16Effects of Fluorination and Thermal Shock on the Photocatalytic Activity of Bi2o3< Nanopowders(Elsevier, 2021) Bouziani, Asmae; Park, Jongee; Ozturk, AbdullahFluorinated Bi2O3 (F-Bi2O3) nanopowder was prepared via fluorination followed by thermal shock of alpha-Bi2O3 nanopowder. The XRD, FTIR, SEM, and DRS characterization techniques were employed to investigate the effects of fluorine (F) insertion into the alpha-Bi2O3 host and the thermal shock from different temperatures. The crystal structure, optical and photocatalytic properties of the F-Bi2O3 nanopowders prepared were researched. The XRD results confirmed the substitution of O2- with F-. The FTIR results revealed that the coordination of Bi atoms changed upon F- substitution. The incorporation of F into the alpha-Bi2O3 host and thermal shock did not influence the morphology but modified the band structure of alpha-Bi2O3, leading to a red-shift in the optical absorption edge. Also, the bandgap narrowed from 2.8 eV to 2.6 eV. The density functional theory calculation proved that the F 2p orbitals were positioned in the valence band (VB), resulting in broader and more spread bands for F-Bi2O3. The results suggested that the photoexcited charge carrier mobility in the valence band (VB) and conduction band (CB) are enhanced upon F insertion into alpha-Bi2O3. The photocatalytic efficiency of the synthesized nanopowders was assessed by the degradation of Bromocresol Green (BG) under visible light illumination. Photocatalytic activity improved upon fluorination. The F-Bi2O3 nanopowders thermally shocked from higher temperatures showed negligible photocatalytic performance. The best photocatalytic performance of 70% BG degradation was realized after 180 min visible irradiation for the F-Bi2O3 nanopowder thermal shocked from 500 degrees C.Article Citation - WoS: 5Citation - Scopus: 6Microporous vanadosilicate films with tailorable V4+/V5+ratio to achieve enhanced visible-light photocatalysis(Elsevier, 2021) Kuzyaka, Duygu; Uzun, Ceren; Yildiz, Ilker; Kaya, Murat; Akata, BurcuThis study investigates the changes induced into the photocatalytic activity under solar light irradiation upon changing the structural film properties and tailor the concentration of defects in microporous vanadosilicate AM6 films. For this purpose, the preparation of AM-6 films with different V4+/V5+ ratios and their utilization as photocatalysts for the decomposition of MB were carried out. Two approaches were used for obtaining AM-6 films with different V4+/V5+ ratios: altering the seed layer coating technique and altering the molar water content of the secondary growth gel. It was seen that dip coating method resulted in an increase in the thickness of the films and it was presumed that the adsorption of MB by AM-6 films was the predominant factor in photocatalytic activity. The second approach of increasing the molar water content of the secondary growth gel provided an increase in the defect concentration resulting in an enhanced photocatalytic activity under the solar light. In the current study, the defect concentration of the prepared films was determined by using XPS and Raman spectroscopy techniques. Accordingly, it was determined that the samples with lower amount V4+/V5+ ratio showed better photocatalytic activity under the solar light irradiation indicating that V5+ cations are responsible for the photocatalytic activity under visible light irradiation. This work provides methods of production of microporous films showing photocatalytic activity under visible light without the requirement of any post-synthesis treatments.Article Citation - WoS: 9Citation - Scopus: 14Bifunctional Praseodymium-Doped Sns2 Thin Films for Photocatalytic and Antibacterial Applications(Elsevier, 2024) Ech-Chergui, Abdelkader Nebatti; Bennabi, Farid; Isik, Mehmet; Khane, Yasmina; Garcia, Francisco Jose Garcia; Kadari, Ali Sadek; Amrani, BouhalouaneThis paper introduces a novel application of bifunctional Pr-doped SnS2 thin films, demonstrating their efficacy in both photocatalytic degradation of dye and antibacterial activities. The thin films were fabricated using an eco-friendly spray-coated method, encompassing undoped and Pr-doped SnS2 variations. The study comprehensively examines the structural, morphological, chemical, photocatalytic, and antibacterial characteristics of these films. The crystal structure of both undoped and Pr-doped SnS2 thin films exhibited hexagonal patterns, prominently favouring the growth in (1 0 1) orientation. Notably, an increase in crystallite size was observed with higher levels of Pr-doping. Raman spectroscopy analysis highlighted a distinct peak at 315 cm -1, corresponding to the A1 g vibrational mode associated with Sn-S bonds along the c-axis of the structure. Employing X ray Photoelectron Spectroscopy (XPS), the presence of essential components - Sn, S, and Pr - within the fabricated thin films was confirmed, consistent with experimental values of undoped and Pr -doped SnS2-x compositions. Importantly, the XPS analysis confirmed the integration of the Pr3+ oxidation state within Pr -doped SnS2 films. The photocatalytic degradation and antibacterial activities of the films were investigated. Notably, the photocatalytic potential of the synthesized materials against Congo Red exhibited a direct correlation with the Pr3+ doping percentage, indicating enhanced pollutant degradation with increasing doping levels. Similarly, the antibacterial performance against Escherichia coli displayed improvement with increasing Pr -doping content, highlighting the promising antimicrobial capabilities of the films. This study presents an innovative avenue to address both organic pollutant degradation and microbial control. By harnessing the attributes of Pr -doped SnS2 thin films, this research introduces a promising strategy for sustainable material applications in environmental purification and improvement in public health.
