Effect of metal-support couplings on the photocatalytic performance of Au-decorated ZnO nanorods
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Effect of metal‑support couplings on the photocatalytic performance of Au‑decorated ZnO nanorods Trung Hieu Nguyen1,2 · T. Anh Thu Do3 · Hong Thai Giang3 · Truong Giang Ho3 · Quang Ngan Pham3 · Minh Tan Man1,2 Received: 13 May 2020 / Accepted: 21 July 2020 © Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract We reported the effectiveness of photocatalysts based on ZnO nanorods in the pollutant degradation. UV–Vis adsorption and photoluminescence (PL) were used to verify the incorporation of the plasmonic Au NPs on the ZnO nanorods. The strong electronic interaction between Au NPs and the defect sites of ZnO can be caused by the resonant coupling near the surface of ZnO, which in turn suppresses the defect-related emission band. We significantly enhanced photocatalytic performance by the coupling ZnO nanorods to the plasmonic gold nanoparticles. Due to the surface plasmon resonance and the localized Au–ZnO Schottky barrier, the Au–ZnO nanorods demonstrated better photocatalytic efficiency (96% in 60 min) than pure ZnO nanorods (only 42% in 60 min) under visible light irradiation of the halogen lamp. The correlation between metalsupport couplings and photocatalytic performance is discussed.
1 Introduction ZnO-based photocatalysts have exhibited excellent photocatalytic water remediation applications, hydrogen gas sensing properties, as well as the conversion of solar energy [1–5]. Understanding electron transfer mechanisms during the photocatalytic activity is a key to improve opportunities for their utilization in the photocatalytics. Semiconductorsensitive strategies to improve the visible light activity of ZnO used as photocatalysts have been reported [6–9]. In general, the photocatalytic activity on the ZnO surfaces occurs three steps: (1) the separation of photogenerated charge carriers resulting from photon absorption allows an electron in the highest energy valence band (VB) state to transition to the lowest state in the conduction band (CB) of * T. Anh Thu Do [email protected] * Minh Tan Man [email protected] 1
Institute of Theoretical and Applied Research, Duy Tan University, Hanoi 100000, Viet Nam
2
Faculty of Natural Sciences, Duy Tan University, Da Nang 550000, Viet Nam
3
Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Hanoi, Viet Nam
ZnO; (2) the photogenerated charge carriers move toward the ZnO surface; and (3) the photoexcited electrons will be absorbed by the oxygen molecule in the solution to produce reactive oxygen species (e.g., ⋅O2−, ⋅OOH, and ⋅OH) at the ZnO surface [10–12]. The active oxygen species oxidize a wide range of organic pollutants rapidly leading to complete degradation of organic dyes. However, the large bandgap of ZnO only absorbs UV radiation that limits commercial photocatalytic applications. Disadvantages of ZnO-based photocatalytic reactions were also caused by other factors including the nature of ion species and active oxygen radicals [10, 11]. To overcome these limitation
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