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Preparation of Bifunctional CuWO 4 ‐Based Heterostructure Nanocomposites for Noble‐Metal‐Free Photocatalysts
Author(s) -
Kannan Selvaraj,
Mohanraj Kannusamy,
Sivakumar Ganesan
Publication year - 2017
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201700877
Subject(s) - nanocomposite , photocurrent , materials science , high resolution transmission electron microscopy , photocatalysis , noble metal , bifunctional , heterojunction , chemical engineering , x ray photoelectron spectroscopy , band gap , nanotechnology , catalysis , metal , transmission electron microscopy , chemistry , optoelectronics , metallurgy , biochemistry , engineering
This article describes the preparation of copper tungstate ( C u W O 4 )‐based heterostructured nanocomposites by facile two‐step polyol assisted hydrothermal‐annealed process. A series of characterization techniques (FESEM, EDS, HRTEM, XPS, XRD and FTIR etc.) were confirmed the formation of type‐I( C u W O 4 / W O 3· 0 . 33 H 2 O ,C u W O 4 / W O 3 ) and type‐II ( C u W O 4 / C u 2 O , C u W O 4 / C u 2 O / C u O , C u W O 4 / C u O )heterojunction as function of pH and annealing temperatures. AlsoW O 3· 0 . 33 H 2 O ,W O 3 ,C u 2 O ,C u 2 O / C u Oand CuO were found as secondary phases withC u W O 4 . These nanocomposites exhibited the enhanced visible light absorption and the band gap ( ca . 1.7 eV) ofC u W O 4 is smaller than the early reported value (2.1‐2.3 eV). In photocatalytic degradation, theC u W O 4 /C u 2 O / C u OandC u W O 4 / W O 3· 0 . 33 H 2 O were showed 1.66 fold times higher and nearly equal apparent rate constant respectively than that ofC u W O 4 . In photoelectrochemical (PEC) studies, theC u W O 4 / C u 2 O ,C u W O 4 /C u 2 O / C u O ,C u W O 4 / W O 3andC u W O 4 / C u Onanocomposites showed more photocurrent density of 3.5, 2.2, 0.71 and 0.41 mA/cm 2 at 1.23 V RHE respectively than CuWO 4 . The existence of dual co‐catalysts (Cu 2 O and CuO) with CuWO 4 , strongly promote the electron‐hole pair separation and migration. Among the nanocomposite, theC u W O 4 / C u Owas showed the similar static photocurrent as that ofC u W O 4 under 1 Sun illumination. The advantage of present work is noble‐metal‐free photocatalysts prepared with binder free, less time, low energy consumption and cost, and environmental benign.