Probing size-dependent defects in zinc oxide using synchrotron techniques: impact on photocatalytic efficiency

doi:10.1039/D3CP02923A

淡江大學機構典藏 > 工學院 > 電機工程學系暨研究所 > 期刊論文 > Item 987654321/125577

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Title:	Probing size-dependent defects in zinc oxide using synchrotron techniques: impact on photocatalytic efficiency
Authors:	A. Kadian, V. Manikandan, K. Dev, V. Kumar, C. J. Yang, B. H. Lin, C. L. Chen, C. L. Dong, K. Asokan, S. Annapoorni
Date:	2023-09
Issue Date:	2024-07-30 12:05:45 (UTC+8)
Publisher:	Royal Society of Chemistry
Abstract:	In the present study, synchrotron-based X-ray diffraction (XRD), X-ray absorption spectroscopy (XAS) and X-ray excited optical luminescence (XEOL) have been used to investigate the induced defect states in metal oxide nanomaterials. Specifically, two synthesis approaches have been followed to develop unique nano-sized peanut-shaped (N-ZnO) nanostructures and micron-sized hexagonal rods (M-ZnO). XANES analysis at the Zn K-edge revealed the presence of defect states with a divalent oxidation state of zinc (Zn2+) in a tetrahedral structure. Furthermore, XAS measurements performed at the Zn L3,2-edge and O K-edge confirm higher oxygen-related defects in M-ZnO, while N-ZnO appeared to have a higher concentration of surface defects due to size confinement. Moreover, the in-line XEOL and time dependent-XEOL measurements exposed the radiative excitonic recombination phenomena occurring in the band-tailing region as a function of absorption length, X-ray energy excitation, and time. Based on the chronology developed in the defect state improvement, a possible energy band diagram is proposed to accurately locate the defect states in the two systems. Furthermore, the increased absorption intensity at the Zn L3,2-edge and the O K-edge under the UV lamp suggests delayed recombination of electrons and holes, highlighting their potential use as photo catalysts. The photocatalytic activity degrading the rhodamine B dye established M-ZnO as a superior catalyst with a rapid degradation rate and significant mineralization. Overall, this work provides valuable insights into ZnO defect states and provides a foundation for efficient advanced materials for environmental or other optoelectronic applications.
Relation:	Physical Chemistry Chemical Physics 25, p.25639-25653
DOI:	10.1039/D3CP02923A
Appears in Collections:	[Graduate Institute & Department of Electrical Engineering] Journal Article

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