Water/oil nanoemulsion-based synthesis of BixSn6-2xSy (0.33 ≤ × ≤ 2.95) semiconductor QDs for efficient photocatalytic degradation of MB dye
Abstract
The development of efficient photocatalysts for the photodegradation of organic dyes in wastewater is highly worthwhile. Herein, the nanoemulsion tactic was utilized to synthesize BixSn6-2xSy (0.33 ≤ x ≤ 2.95) photocatalysts with morphological structures that changed from nanowhiskers to quantum dots (QDs). The optical properties of these materials were examined by UV-visible absorbance spectroscopy and photoluminescence, while Mott-Schottky analysis was utilized to study their electronic properties. BixSn6-2xSy materials exhibit appreciable absorption in the UV-visible light range with a direct band gap that increases from 1.23 to 1.46 eV. Both crystal structure and composition greatly affect the photocatalytic activity of BixSn6-2xSy semiconductors. Among the various synthesized photocatalysts, BiSn4S4.5 can efficiently photodegrade methylene blue dye (MB) in the shortest time under UV-visible light. The photocatalytic activity is positively affected by the change of crystal structure from orthorhombic to cubic symmetry. Based on the Mott-Schottky plots, the flat band potential (Efb) and the semiconductor behavior of the fabricated BixSn6-2xSy nanomaterials were determined. The obtained Efb values for SnS, Bi0.33Sn5.34S5.8, BiSn4S5.5, and Bi2.14Sn1.71S4.7 are -0.18 V, -0.42 V, -0.53 V, and -0.51 V (vs. Ag/AgCl), respectively. The Efb value is clearly shifted towards more negative potential values with increasing the Bi molar ratio (x). However, Bi2.95Sn0.1S4.5 semiconductor was found to be of n-type character, having a positive Efb value of +0.66 V (vs. Ag/AgCl). Photocurrent and EIS responses confirm the high stability and photocatalytic activity of BiSn4S5.5, which also achieves the lowest charge transfer resistance. The modified electronic properties of the BixSn6-2xSy semiconductors significantly improve their photocatalytic activity, rendering them to be promising absorbers for sunlight harvesting applications.
Citation
Negem , M , Miller , D , Irvine , J & Heakal , F E-T 2023 , ' Water/oil nanoemulsion-based synthesis of Bi x Sn 6-2x S y (0.33 ≤ × ≤ 2.95) semiconductor QDs for efficient photocatalytic degradation of MB dye ' , Environmental Science and Pollution Research , vol. 30 , pp. 58998-59012 . https://doi.org/10.1007/s11356-023-26596-z
Publication
Environmental Science and Pollution Research
Status
Peer reviewed
ISSN
0944-1344Type
Journal article
Description
Funding: Open-access funding is provided by the Science, Technology & Innovation Funding Authority (STDF) in cooperation with the Egyptian Knowledge Bank (EKB). The authors would like to thank the University of St Andrews and the Egyptian Government for funding this work.Collections
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