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Photoelectrochemical activity of graphene quantum dots/hierarchical porous TiO2 photoanode

Azimirad, R ; Sharif University of Technology | 2017

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  1. Type of Document: Article
  2. DOI: 10.1016/j.jallcom.2017.05.301
  3. Publisher: Elsevier Ltd , 2017
  4. Abstract:
  5. In this study, initially graphene quantum dots (GQDs) were synthesized by an electrochemical technique and hierarchical porous TiO2 were made by a sol – gel method. Subsequently, GQDs/hierarchical porous TiO2 nanocomposites were prepared by two different methods for the purpose of comparison: spin coating (SC) and electrophoretic (EP) deposition. The GQDs/hierarchical porous TiO2 nanocomposites were characterized by various analytical methods including field emission scanning electron microscopy, atomic force microscopy, transmission electron microscopy, high resolution transmission electron microscopy, Fourier transform infra-red spectroscopy, photoluminescence spectroscopy and ultraviolet–visible spectroscopy. Under visible light irradiation, photoanodes made of the hierarchical porous TiO2, EP- GQDs/hierarchical porous TiO2 and SC- GQDs/hierarchical porous TiO2 nanocomposite produced the photocurrent densities of about 1.86, 3.29 and 6.35 A/m2, respectively. The results showed that the nanocomposites prepared by the SC technique exhibit a higher photoelectrochemical (PEC) activity as compared to both the EP deposited composite and the pure hierarchical porous TiO2. Finally, the photoenhancement was described based on a charge transfer mechanism. © 2017 Elsevier B.V
  6. Keywords:
  7. Graphene quantum dots ; Photocatalyst ; TiO2 ; Atomic force microscopy ; Charge transfer ; Electrochemistry ; Electron microscopy ; Field emission microscopes ; Graphene ; Nanocomposites ; Nanocrystals ; Photocatalysts ; Photoelectrochemical cells ; Photoluminescence spectroscopy ; Scanning electron microscopy ; Semiconductor quantum dots ; Semiconductor quantum wells ; Sols ; Titanium dioxide ; Charge transfer mechanisms ; Electrochemical techniques ; Field emission scanning electron microscopy ; Fourier transform infra reds ; Hierarchical porous ; Photocurrent density ; Photoelectrochemicals ; Visible-light irradiation ; High resolution transmission electron microscopy
  8. Source: Journal of Alloys and Compounds ; Volume 721 , 2017 , Pages 36-44 ; 09258388 (ISSN)
  9. URL: https://www.sciencedirect.com/science/article/abs/pii/S0925838817319187