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      Morphological control of mesoporosity and nanoparticles within Co3O4-CuO electrospun nanofibers: quantum confinement and visible light photocatalysis performance

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      Author(s)
      Pradhan, A. C.
      Uyar, Tamer
      Date
      2017-09
      Source Title
      ACS Applied Materials and Interfaces
      Print ISSN
      1944-8244
      Publisher
      American Chemical Society
      Volume
      9
      Issue
      41
      Pages
      35757 - 35774
      Language
      English
      Type
      Article
      Item Usage Stats
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      Abstract
      The one-dimensional (1D) mesoporous and interconnected nanoparticles (NPs) enriched composite Co3O4-CuO nanofibers (NFs) in the ratio Co:Cu = 1/4 (Co3O4-CuO NFs) composite have been synthesized by electrospinning and calcination of mixed polymeric template. Not merely the mesoporous composite Co3O4-CuO NFs but also single mesoporous Co3O4 NFs and CuO NFs have been produced for comparison. The choice of mixed polymer templates such as polyvinylpyrrolidone (PVP) and polyethylene glycol (PEG) for electrospinning is responsible for the formation of 1D mesoporous NFs. The HR-TEM result showed evolution of interconnected nanoparticles (NPs) and creation of mesoporosity in all electrospun NFs. The quantum confinement is due to NPs within NFs and has been proved by the surface-enhanced Raman scattering (SERS) study and the UV-vis-NRI diffuse reflectance spectra (DRS). The high intense photoluminescence (PL) spectra showing blue shift of all NFs also confirmed the quantum confinement phenomena. The lowering of PL spectrum after mixing of CuO in Co3O4 nanofibers framework (Co3O4-CuO NFs) proved CuO as an efficient visible light response low cost cocatalyst/charge separator. The red shifting of the band gap in composite Co3O4-CuO NFs is due to the internal charge transfer between Co2+ to Co3+ and Cu2+, proved by UV-vis absorption spectroscopy. Creation of oxygen vacancies by mixing of CuO and Co3O4 also prevents the electron-hole recombination and enhances the photocatalytic activity in composite Co3O4-CuO NFs. The photocurrent density, Mott-Schottky (MS), and electrochemical impedance spectroscopy (EIS) studies of all NFs favor the high photocatalytic performance. The mesoporous composite Co3O4-CuO NFs exhibits high photocatalytic activity toward phenolic compounds degradation as compared to the other two NFs (Co3O4 NFs and CuO NFs). The kinetic study of phenolic compounds followed first order rate equation. The high photocatalytic activity of composite Co3O4-CuO NFs is attributed to the formation of mesoporosity and interconnected NPs within NFs framework, quantum confinement, extended light absorption property, internal charge transfer, and effective photogenerated charge separations.
      Keywords
      Electrospinning
      Mesoporous
      Nanofibers
      Phenolic compounds
      Quantum confinement
      Visible light
      Absorption spectroscopy
      Charge transfer
      Complexation
      Electrochemical impedance spectroscopy
      Electromagnetic wave absorption
      Electrospinning
      Energy gap
      Light
      Light absorption
      Mesoporous materials
      Mixing
      Nanofibers
      Nanoparticles
      Oxygen vacancies
      Phenols
      Photocatalysis
      Polymers
      Quantum confinement
      Raman scattering
      Semiconductor quantum wells
      Spinning (fibers)
      Surface scattering
      Synthesis (chemical)
      Ultraviolet spectroscopy
      Diffuse reflectance spectrum
      High photocatalytic activities
      Mesoporous
      Phenolic compounds
      Surface enhanced Raman Scattering (SERS)
      UV-Vis absorption spectroscopy
      Visible light
      Visible-light photocatalysis
      Copper oxides
      Permalink
      http://hdl.handle.net/11693/37284
      Published Version (Please cite this version)
      https://doi.org/10.1021/acsami.7b09026
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      • Institute of Materials Science and Nanotechnology (UNAM) 2260
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