Sains
Malaysiana 41(7)(2012): 893–899
Fotoelektrod Tungsten Trioksida Terdop
Nikel untuk Tindak Balas Pembelahan
Air Fotoelektrokimia
(Nickel-doped Tungsten Trioxide
Photoelectrodes for Photoelectrochemical
Water Splitting Reaction)
Ng Kim Hang &
Mohammad Bin Kassim
Pusat Pengajian Sains
Kimia dan Teknologi Makanan, Fakulti Sains dan Teknologi,
Universiti Kebangsaan
Malaysia, 43600 UKM Bangi,
Selangor, Malaysia
Lorna Jeffery Minggu*
Institut Sel Fuel, Universiti Kebangsaan Malaysia, 43600
UKM Bangi, Selangor, Malaysia
Mohammad Hafizuddin
Haji Jumali
Pusat Pengajian Fizik
Gunaan, Fakulti Sains dan Teknologi, Universiti
Kebangsaan Malaysia
43600 UKM Bangi,
Selangor, Malaysia
Diserahkan: 19
Oktober 2011 / Diterima: 30 Januari 2012
ABSTRAK
Tungsten trioksida (WO3)
merupakan salah satu fotomangkin yang berpotensi dalam aplikasi penjanaan gas
hidrogen daripada tindak balas pembelahan air. Dalam kajian ini, pelbagai komposisi
filem nipis WO3 terdop nikel dihasilkan pada kaca stanum(IV) oksida terdop fluorin (FTO) dengan menggunakan asid tungstik dan nikel(II) asetat
sebagai bahan pemula. Selepas disepuhlindap pada 500°C selama 30 min, sampel
filem nipis ini dicirikan dengan menggunakan SEM, XRD, spektrofotometer UV-Vis serta analisis fotoelektrokimia (PEC). WO3 terdop
nikel mempunyai saiz zarah yang lebih besar berbanding sampel WO3 tulen
dan mempunyai struktur hablur monoklinik. Jurang
tenaga WO3 terdop nikel yang dianggarkan daripada spektrum UV-Vis
dengan menggunakan formula Tauc adalah lebih kecil berbanding jurang tenaga
bagi WO3 tulen. Ujian aplikasi PEC di
bawah sinaran lampu xenon menunjukkan kecekapan penghasilan gas hidrogen oleh
filem WO3 terdop nikel yang digunakan sebagai fotoanod telah
dipertingkatkan.
Kata
kunci: Fotoanod; pembelahan air secara langsung; penjanaan hidrogen; sel
fotoelektrokimia; tungsten trioksida terdop nikel
ABSTRACT
Tungsten
trioxide (WO3) is one of the photocatalysts with a
high potential for application in water splitting reaction to produce hydrogen
gas. In this paper, different compositions of nickel-doped WO3 thin films on fluorine-doped tin oxide (FTO) glass were produced from tungstic acid and nickel(II) acetate. After annealing at 500°C for 30 min, the
thin films were characterized using SEM, XRD, UV-Vis spectrophotometer and photoelectrochemical (PEC) test. Ni-doped WO3 exhibited
an increased grain size compared to undoped WO3 and
adopted a monoclinic structure. Optical band gaps calculated with Tauc formula
from UV-Vis absorption data showed a reduction in band gap for Ni-doped WO3. Under the irradiation of xenon lamp, the efficiency of
hydrogen production by nickel-doped WO3 thin
films were improved.
Keywords:
Direct water splitting; hydrogen production; nickel-doped tungsten trioxide;
photoanode; photoelectrochemical cell
RUJUKAN
Chawla,
A.K., Singhal, S., Gupta, H.O & Chandra, R. 2009. Influence of nitrogen
doping on the sputter-deposited WO3 films. Thin Solid Films 518:
1430-1439.
Cheng,
X.F., Leng, W.H., Liu, D.P., Zhang, J.Q. & Cao C.N. 2007. Enhanced
photoelectrocatalytic performance of Zn-doped WO3 photocatalysts for nitrite
ions degradation under visible light. Chemosphere 68: 1976-1984.
Dholam, R., Patel, N., Adami, M. & Niotekko, A. 2009. Hydrogen production by photocatalytic water-splitting using Cr- or Fe-doped TiO2 composite thin films photocatalyst. International
Journal of Hydrogen Energy 34: 5337-5346.
Enesca, A., Duta, A. & Schoonman, J. 2007. Study of photoactivity of tungsten trioxide (WO3) for water
splitting. Thin Solid Films 515: 6371-6374.
Esfandarani,
M.T., Minggu, L.J., Daud, W.R.W. & Kassim, M.B. 2010. Synthesis and charaterization of Fe2O3/SiO2/TiO2 composite thin
film on different substrates for water splitting. Journal of New
Materials for Electrochemical Systems 13: 333-335.
Fardindoost, S., Iraji zad, A., Rahimi, F. & Ghasempour,
R. 2010. Pd doped WO3 films prepared by sol–gel
process for hydrogen sensing. International Journal of Hydrogen Energy 35:
854-860.
Gavrilyuk,
A.I. 2009. Application of WO3 thin films for enhancement of photolysis in AgCl. Solar Energy Materials & Solar Cells 93: 1885-1895.
Hameed, A., Gondal, M.A. & Yamani, Z.H. 2004. Effects of transition metal doping on photocatalytic activity of WO3 for water
splitting under laser illumination: role of 3d-orbitals. Catalysis
Communications 5: 715-719.
Hong,
S.J., Jun, H., Borse, P.H. & Lee, J.S. 2009. Size effect
of WO3 nanocrystals for photooxidation of water in particulate
suspension and photoelectrochemical film systems. International
Journal of Hydrogen Energy 34: 3234-3242.
Hutchins, M.G., Abu-Alkhair, O., El-Nahass, M.M. & Abd
El-Hady, K. 2006. Structural and
optical characterisation of thermally evaporated tungsten trioxide (WO3)
thin films. Materials Chemistry and Physics 98: 401-405.
Karuppasamy,
K.M. & Subrahmanyam, A. 2008. The electrochromic and photocatalytic
properties of electron beam evaporated vanadium-doped tungsten oxide thin
films. Solar Energy Materials & Solar Cells 92: 1322-1326.
Li, W., Li, J., Wang, X., Ma, J. & Chen, Q. 2010. Photoelectrochemical and physical properties of WO3 films obtained by the polymeric precursor method. International
Journal of Hydrogen Energy 35: 13137-13145.
Liu, H., Peng, T., Ke, D., Peng, Z. & Yan, C. 2007. Preparation and photocatalytic activity of dysprosium doped tungsten trioxide
nanoparticles. Materials Chemistry and Physics 104: 377-383.
Minggu,
L.J., Wan, R.W.D. & Mohammad B. K. 2010. An overview of
photocells and photoreactors for photoelectrochemical water splitting. International
Journal of Hydrogen Energy 35: 5233-5244.
Memar,
A., Wan, R.W.D., Hosseini, S., Eftekhari, E. & Minggu, L.J. 2010. Study on
photocurrent of bilayers photoanodes using different combination of WO3 and Fe2O3. Solar Energy 84: 1538- 44.
Ni, M., Leung, M.K.H., Leung, D.Y.C. & Sumathy, K. 2007. A review and recent developments in photocatalytic water-splitting
using TiO2 for hydrogen production. Renewable and
Sustainable Energy Reviews 11: 401-425.
Nowotny, J., Sorrell, C.C., Sheppard, L.R. & Bak, T.
2005. Solar-hydrogen: Environmentally safe fuel for the future. International
Journal of Hydrogen Energy 30: 521-544
Patil,
P. S., Mujawar, S. H., Inamdar, A.I. Shinde, P.S., Deshmukh, H.P. & Sadale,
S.B. 2005. Structural, electrical and optical properties of TiO2 doped WO3 thin films. Applied Surface Science 252: 1643-1650.
Redecka, M., Rekas, M., Trenczek-Zajac, A. & Zakrzewska,
K. 2008. Importance of the band gap energy and
flat band potential for application of modified TiO2 photoanodes in
water photolysis. Journal of Power Sources 181: 46-55.
Redecka, M., Sobas, P., Wierzbicka, M. & Rekas, M. 2005. Photoelectrochemical properties of
undoped and Ti-doped WO3. Physica B 364: 85-92.
Scarminio,
J., Urbano, A. & Gardes, B. 1999. The Beer-Lambert law for electrochromic
tungsten oxide thin films. Materials Chemistry and Physics 61: 143-146.
Sivakumar, R., Jayachandran, M. & Sanjeeviraja, C. 2004. Studies on the effect of substrate temperature on (VI-VI) textured tungsten
oxide (WO3) thin films on glass, SnO2:F substrates by PVD:EBE technique for electrochromic devices. Materials
Chemistry and Physics 87: 439-445.
Solarska, R., Alexander, B.D., Braun, A., Jurczakowski, R.,
Fortunato, G., Stiefel, M., Graule, T. & Augustynski, J. 2010. Tailoring the morphology of WO3 films with substitutional cation
doping: Effect on the photoelectrochemical properties. Electrochimica Acta 55:
7780-7787.
Song, S., Wang, C., Hong, F., He, Z., Cai, Q. & Chen, J.
2011. Gallium- and iodine-co-doped titanium dioxide for
photocatalytic degradation of 2-chlorophenol in aqueous solution: Role of
gallium. Applied Surface Science 257: 3427-3432.
Su, L., Dai, Q. & Lu, Z. 1999. Spectroelectrochemical and photoelectrochemical studies of
electrodeposited tungsten trioxide films. Spectrochimica Acta Part A55:
2179-2185.
Su,
L., Wang, H. & Lu, Z. 1998. All-solid-state electrochromic window of
prussian blue and electrodeposited WO3 film with poly(ethylene
oxide) gel electrolyte. Material Chemistry and Physics 56: 226-270.
Sun, Y., Murphy, C.J., Reyes-Gil, K.R., Reyes-Garcia, E.A.,
Thornton, J.M., Morris, N.A. & Raftery, D. 2009. Photoelectrochemical and structural characterization of carbon-doped WO3 films prepared via spray pyrolysis. International Journal of Hydrogen Energy 34: 8476-8484.
Tong, M. Dai, G. & Gao, D. 2001. WO3 thin film sensor prepared by sol-gel technique and its low-temperature
sensing properties to trimethylamine. Materials Chemistry and Physics 69:
176-179.
Yagi, M., Maruyama, S., Sone, K.,
Nagai, K. & Norimatsu, T. 2008. Preparation and
photoelectrocatalytic activity of a nano-structured WO3 platelet film. Journal
of Solid State Chemistry 181: 175-182.
*Pengarang untuk surat-menyurat; email: lorna_jm@ukm.my
|