Photoelectrocatalytic degradation of methylene blue using ZnO nanorods fabricated on silicon substrates
da Rosa, Ana Paula Pereira, Cavalcante, Rodrigo Pereira, da Silva, Thalita Ferreira, Gozzi, FábioORCID: 0000-0002-4993-7166, Byrne, Conor, McGlynn, EndaORCID: 0000-0002-3412-9035, Casagrande, Gleison AntônioORCID: 0000-0002-1667-913X, de Oliveira, Silvio César and Machulek Jr, AmilcarORCID: 0000-0002-4632-4647
(2020)
Photoelectrocatalytic degradation of methylene blue using ZnO nanorods fabricated on silicon substrates.
Journal of Nanoscience and Nanotechnology, 20
(2).
pp. 1177-1188.
ISSN 1533-4880
ZnO nanorods were grown on silicon (Si) substrates by two techniques: (i) Chemical Bath Deposition (CBD) and (ii) a CBD seed layer combined with Carbothermal Reduction Vapor Phase Transport (CTR-VPT). The structured ZnO nanorods were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and contact angle measurments. The photoelectrochemical property of ZnO nanorods were analyzed by linear voltammetry under UV-ABC light excitation. Using the ZnO nanorod samples as photoanodes, the removal of methylene blue (MB) as a representative organic compound was studied by the photoelectrocatalytic (PEC) technique applying a potential (E) of 0.6 V. For comparison purposes, experiments were performed under the same conditions using photocatalysis (PC), direct photolysis and using samples of pure Si (support material) as working electrodes in PEC. XRD analyses of ZnO prepared by both methods showed the expected ZnO wurtzite phase and a preferred c-axial orientation in the growth of the nanorods. The presence of ZnO was further confirmed by XPS and contact angle measurements showed that ZnO grown by CBD (ZnO/CBD) had a slightly hydrophobic behavior while ZnO grown by CTR-VPT (ZnO/CTR-VPT) is hydrophilic. Both ZnO sample types were shown to be photoactive, with ZnO/CBD showing higher resultant photocurrent compared to ZnO/CTR-VPT. For the degradation of MB 53% of the compound was removed using ZnO/CBD as a working electrode, while using the ZnO/CTR-VPT electrode led to a removal of 43% of MB. However, direct photolysis alone removed 39% of the MB. The lower removal of MB using ZnO/CTR-VPT samples was related to surface dissociation during the degradation process. The results show that ZnO nanorods prepared by the CBD techique are a promising photoelectrode for PEC applications. Our data also indicate that CTR-VPT-grown nanorods produce uniform nanorod arrays, but this uniform nanostructure deposit does not lead to any increase in PEC activity.
Metadata
Item Type:
Article (Published)
Refereed:
Yes
Uncontrolled Keywords:
Chemical Bath Deposition; Methylene Blue; Photoelectrocatalysis; Si/ZnO Heterojunction;
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Funders:
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (Capes, Finance Code 001), Fundação de Apoio ao Desenvolvimento do Ensino, Ciência e Tecnologia do Estado de Mato Grosso do Sul, Science Foundation Ireland under the SFI PI award 13/IA/1955
ID Code:
23635
Deposited On:
28 Aug 2019 10:55 by
Enda Mcglynn
. Last Modified 28 Aug 2019 10:55