Band gap engineering of CeO2 nanostructure using an electrochemically active biofilm for visible light applications

Title
Band gap engineering of CeO2 nanostructure using an electrochemically active biofilm for visible light applications
Author(s)
조무환이진태칸모하마드만숩모드안사리사지드안자리Shafeer Kalathil[Shafeer Kalathil]
Keywords
CERIUM OXIDE NANOPARTICLES; OXYGEN VACANCIES; PHOTOELECTROCHEMICAL PERFORMANCE; ELECTRICAL-CONDUCTIVITY; TIO2 NANOPARTICLES; OPTICAL-PROPERTIES; BIO-HYDROGEN; NANORODS; DEFECT; PHOTOCATALYSIS
Issue Date
201404
Publisher
ROYAL SOC CHEMISTRY
Citation
RSC ADVANCES, v.4, no.32, pp.16782 - 16791
Abstract
Narrowing the optical band gap of ceriumoxide (CeO2) nanostructures is essential for visible light applications. This paper reports a green approach to enhance the visible light photocatalytic activity of pure CeO2 nanostructures (p-CeO2) through defect-induced band gap narrowing using an electrochemically active biofilm (EAB). X-ray diffraction, UV-visible diffuse reflectance/absorption spectroscopy, X-ray photoelectron spectroscopy, electron paramagnetic resonance spectroscopy, Raman spectroscopy, photoluminescence spectroscopy and high resolution transmission electron microscopy confirmed the defect-induced band gap narrowing of the CeO2 nanostructure (m-CeO2). The structural, optical, photocatalytic and photoelectrochemical properties also revealed the presence of structural defects caused by the reduction of Ce4+ to Ce3+ as well as an increase in the number of oxygen vacancies. The as-modified CeO2 (mCeO(2)) nanostructure exhibited substantially enhanced, visible light-driven photoactivity for the degradation of 4-nitrophenol (4-NP) and methylene blue (MB) compared to the p-CeO2 nanostructure. The enhancement in visible light performance was attributed to defects (Ce3+ and oxygen vacancy), resulting in band gap narrowing and a high separation efficiency of photogenerated electron-hole pairs. Photoelectrochemical investigations also showed a significantly-enhanced separation efficiency of the photogenerated electron-hole charge carriers in the m-CeO2 nanostructure under visible light irradiation. The DC electrical conductivity of m-CeO2 showed higher electrical conductivity than p-CeO2 under ambient conditions. This study provides a new biogenic method for developing narrow band gap semiconductor nanostructures for efficient visible light driven photocatalysis and photoelectrode applications.
URI
http://hdl.handle.net/YU.REPOSITORY/32616http://dx.doi.org/10.1039/c4ra00861h
ISSN
2046-2069
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공과대학 > 화학공학부 > Articles
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