Sains Malaysiana 40(12)(2011): 1421–1427

Electrochemical Behaviour of Ni and Ni-PVC Electrodes for the Electroxidation of Ethanol

(Tingkah Laku Elektrokimia Pengoksidaan Etanol Menggunakan Elektrod Ni dan Ni-PVC)

Mohd Syafiq Hamdan¹, Norazzizi Nordin¹, Siti Fathrita Mohd Amir¹, Riyanto² & Mohamed Rozali Othman^1. *

¹School of Chemical Sciences and Food Technology, Faculty of Science and Technology

Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor D.E. Malaysia

²Universitas Islam Indonesia, Yogyakarta, Indonesia

Received: 2 December 2010 / Accepted: 16 May 2011

ABSTRACT

In this study, two nickel based electrodes were prepared; nickel foil and nickel-polyvinylchloride (Ni-PVC), in order to study their electrochemical behavior using cyclic voltammetry, CV and chronocoulometry, CC. Ni electrode was prepared from Ni metal foil while Ni-PVC electrode was prepared by mixing a weighed portion of Ni powder and PVC in THF solvent, swirled until the suspension was homogeneous and drying the suspension in an oven at 50oC for 3 h. The dry sample was then placed in a 1 cm diameter stainless steel mould and pressed at 10 ton/cm2. From CV data, Ni-PVC electrode showed a better electrochemical behavior compared to Ni metal foil electrode. The use of Ni-PVC electrode at higher concentration of supporting electrolyte (1.0 M KOH) was better than at lower concentration of the same supporting electrolyte in electroxidation of ethanol. In addition to acetic acid, the oxidation of ethanol also produced ethyl acetate and acetaldehyde.

Keywords: Acetic acid yield; chronocoulometry; cyclic voltammetry

ABSTRAK

Elektrod kepingan nikel dan nikel-polivinilklorid (Ni-PVC) telah diguna dalam kajian ini untuk mengkaji sifat elektrokimianya menggunakan kaedah Voltametri Berkitar (CV) dan Kronokoulometri (CC). Kepingan logam Ni telah dipotong mengikut saiz 1 × 1 cm2 untuk dijadikan elektrod Ni. Manakala elektrod Ni-PVC telah dibuat dengan menambahkan serbuk Ni dan PVC mengikut berat tertentu ke dalam tetrahidrofuran (THF), dikacau sehingga homogen kemudian dikeringkan di dalam oven pada suhu 50oC selama 3 jam. Seterusnya, serbuk dimasukkan ke dalam acuan dan dikenakan tekanan 10 ton/cm2 untuk membentuk pelet. Data CV yang diperoleh menunjukkan elektrod Ni-PVC mempunyai sifat elektrokimia lebih baik berbanding elektrod kepingan Ni. Semasa proses pengoksidaan elektrokimia etanol, penggunaan elektrod Ni-PVC dengan elektolit sokongan berkepekatan tinggi (1.0 M KOH) adalah lebih baik jika dibanding penggunaannya pada elektrolit sokongan berkepekatan rendah (0.1 M KOH). Selain asid asetik, etil asetat dan asetaldehid juga terhasil daripada pengoksidaan etanol.

Kata kunci: Hasil asid asetik; kronokoulometri; voltametri berkitar

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*Corresponding author; email: rozali@ukm.my