Malaysian
Journal of Analytical Sciences Vol 20 No 4 (2016): 923 - 930
DOI:
http://dx.doi.org/10.17576/mjas-2016-2004-28
FABRICATION AND CHARACTERIZATION OF Fe-DOPED
TUNGSTEN TRIOXIDE PHOTOELECTRODES IN AQUEOUS MEDIUM USING TUNGSTIC ACID AND
FERROCENE AS STARTING MATERIALS
(Pembuatan dan Pencirian Fotoelektrod Tungsten Trioksida Terdop Fe
Dalam Medium Akueus Dengan Asid Tungstik dan Ferosin Sebagai Bahan Permulaan)
Ng
Kim Hang 1, Nurul Akmal Jaafar1, Lorna Jeffery Minggu
1*, Mohammad bin Kassim1,2
1Fuel Cell
Institute
2School of Chemical Sciences and
Food Technology, Faculty of Science and Technology
Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia
*Corresponding author: lorna_jm@ukm.edu.my
Received: 5
February 2016; Accepted: 22 April 2016
Abstract
Different
compositions of Fe-doped tungsten trioxide thin films were synthesized on
fluorine-doped tin oxide (FTO) glass substrate by sol-gel method, with
ferrocene and tungstic acid as starting materials. The synthesized thin films
was characterized with X-ray diffraction (XRD), scanning electron microscope
(SEM), UV/Vis spectrophotometer and photoelectrochemical (PEC) analysis. The
results show that the surface morphology of the thin films became rough and the
grain size increased along with the concentration of Fe. Monoclinic structure
of tungsten trioxide was obtained for all doped and undoped WO3 and
red-shift can be observed from UV-vis spectrum. Band gap reduced from 2.74 eV
of undoped WO3 thin films to 2.60 eV of 20 % Fe-doped WO3
thin films. Photoactivities of all Fe-doped WO3 are higher than
undoped thin films. The highest photoactivities contributed by 5 % Fe-doped WO3
films with photocurrent densities measured was 0.148 mA/cm2, which is 3
times higher compared to undoped WO3.
Keywords: Fe-doped WO3,
direct water splitting, photoelectrochemical cell, photoanode
Abstrak
Filem nipis tungsten trioksida terdop Fe berbagai
komposisi telah disediakan di atas kaca substrat FTO (fluorine-doped tin oxide)
dengan kaedah sol-gel, dengan menggunakan ferosin dan asid tingstik sebagai
bahan pemula. Filem nipis yang terhasil kemudiannya dicirikan dengan pembelauan
sinar X (XRD), mikroskopi elektron pengimbasan (SEM), UV/Vis spektrofotometer
dan analisis fotoelektrokimia. Keputusan menunjukkan bahawa morfologi permukaan
filem nipis menjadi kasar dan saiz butiran bertambah dengan penambahan
kepekatan Fe. Tungsten trioksida yang berstruktur monoklinik telah dihasilkan
dan anjakan merah telah diperhatikan di dalam spectrum UV-vis. Jurang tenaga
telah berkurang dari 2.74 eV (WO3 tulen) kepada 2.60 eV (20 % Fe-dop
WO3). Fotoaktiviti WO3 terdop Fe adalah lebih tinggi
berbanding WO3 tulen. Fotoaktiviti yang tertinggi dicatatkan oleh
filem 5 % WO3 terdop Fe dengan ketumpatan fotoarus 0.148 mA/cm2.
Ia adalah 3 kali ganda lebih tinggi berbanding WO3 tulen.
Kata
kunci:
Fe-dop WO3, pembelahan air secara langsung, sel fotoelektrokimia,
fotoanod
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