Sains Malaysiana 40(3)(2011): 227–230

Formation of High Aspect Ratio TiO₂ Nanotube Arrays by Anodization of Ti Foil in Organic Solution

(Penghasilan Susunan Nanotiub TiO₂ Bernisbah Aspek Tinggi melalui Proses Penganodan Kerajang Ti dalam Larutan Organik)

Srimala Sreekantan*, Roshasnorlyza Hazan, Khairul Arifah Saharudin & Lai Chin Wei

School of Materials and Mineral Resources Engineering, Engineering Campus

Universiti Sains Malaysia, 14300 Nibong Tebal, Seberang Prai Selatan, Pulau Pinang, Malaysia

Ishak Mat

Advanced Medical and Dental Institute, Kompleks EUREKA

Universiti Sains Malaysia, 11800 Pulau Pinang, Malaysia

Diserahakan: 7 Julai 2010 / Diterima: 3 September 2010

ABSTRACT

Titanium oxide (TiO₂) nanotubes were successfully formed by anodization of pure titanium foil in a standard two-electrode bath consisting of ethylene glycol solution containing 5 wt% NH4F. The pH of the solution was ∼ 7 and the anodization voltage was 60 V. It was observed that such anodization condition results in ordered arrays of TiO₂ nanotubes with smooth surface and a very high aspect ratio. It was observed that a minimum of 1 wt % water addition was required to form well ordered TiO₂ nanotubes with length of approximately 18.5 μm. As-anodized sample, the self-organized TiO₂ nanotubes have amorphous structure and annealing at 500^oC of the nanotubes promote formation of anatase and rutile phase. Photocatalytic activity of well ordered TiO₂ nanotubes with two different lengths was evaluated by measuring the degradation of methyl orange (MO). The elaboration of this observation is described in detail in this paper.

Keywords: Anodization; ethylene glycol; phase transformation; TiO₂ nanotubes

ABSTRAK

Nanotiub titanium dioksida (TiO₂) berjaya dihasilkan melalui penganodan kerajang titanium tulen dalam takungan 2-elektrod piawai dengan elekrolit larutan etilena glikol yang mengandungi 5% berat NH4F. pH larutan ialah ~ 7 dan voltan penganodan ialah 60 V. Didapati bahawa keadaan penganodan mempengaruhi susunan nanotiub TiO₂, permukaan dinding lebih licin dengan nisbah aspek yang lebih tinggi. Didapati tambahan minimum 1% berat air diperlukan untuk menghasilkan nanotiub TiO₂ yang tersusun dengan teratur dan panjang kira-kira 18.5 μm. Sampel yang dianod menghasilkan nanotiub TiO₂ tersusun sendiri yang mengandungi struktur amorfus dan penyepuhlindapan nanotiub pada 500^oC menggalakkan pembentukan fasa anatas dan rutil. Aktiviti foto-pemangkin bagi nanotiub TiO₂ yang tersusun dengan panjang yang berbeza ditentukan dengan mengukur degradasi metil oren (MO). Penerangan lanjut mengenai pemerhatian ini diterangkan secara terperinci di dalam kertas ini.

Kata kunci: Etilena glikol; penganodan; nanotiub TiO₂; transformasi fasa

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*Pengarang untuk surat-menyurat; email: srimala@eng.usm.my