Sains Malaysiana 49(12)(2020): 3197-3208

http://dx.doi.org/10.17576/jsm-2020-4912-31

Pengaruh Agen Kimia Berbeza terhadap Penguraian Terma dan Pembentukan Fasa Bahan La_0.6SR_0.4CoO_{3- δ} yang Disediakanmelalui Kaedah Sol-Gel

(Influence of Different Chemical Agents on the Thermal Decomposition and Phase Formation of La_0.6Sr_0.4CoO_3-δ Material Prepared through Sol-Gel Method)

ABDULLAH ABDUL SAMAT^1,2, MAHENDRA RAO SOMALU³*, ANDANASTUTI MUCHTAR^3,4, HAMIMAH ABD. RAHMAN⁵ & NAFISAH OSMAN⁶

¹Fakulti Teknologi Kejuruteraan, Universiti Malaysia Perlis (UniMAP), Kampus UniCITI ALAM, Sungai Chuchuh, Padang Besar 02100, Perlis, Malaysia

²Pusat Kecemerlangan Sistem Tanpa Pemandu (Unmanned Aerial Systems), Universiti Malaysia Perlis (UniMAP), 01000 Kangar, Perlis, Malaysia

³Institut Sel Fuel, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor Darul Ehsan, Malaysia

⁴Jabatan Kejuruteraan Mekanikal dan Pembuatan, Fakulti Kejuruteraan dan Alam Bina, 43600 UKM Bangi, Selangor Darul Ehsan, Malaysia

⁵Fakulti Kejuruteraan Mekanikal & Pembuatan, Universiti Tun Hussein Onn Malaysia, 84600 Parit Raja, Batu Pahat, Johor Darul Takzim, Malaysia

⁶Fakulti Sains Gunaan, Universiti Teknologi MARA, 02600 Arau, Perlis, Malaysia

Received: 6 August 2020/Accepted: 11 September 2020

ABSTRAK

Sifat penguraian terma dan pembentukan fasa bahan lantanum strontium kobalt oksida, La_0.6Sr_0.4CoO_3-δ (LSC) yang disediakan melalui kaedah sol-gel berbantu agen kimia berbeza, iaitu agen serakan, agen pempolimeran dan agen permukaan aktif atau surfaktan telah dicirikan secara sistematik masing-masing melalui analisis termogravimetrik (TG) dan pembelauan sinar-X (XRD). Penguraian terma bahan organik dan bahan bukan organik yang tidak diperlukan dalam serbuk pelopor bahan LSC telah lengkap pada suhu kurang daripada 1000 °C bagi serbuk pelopor yang disediakan dengan menggunakan agen serakan dan agen pempolimeran, dan suhu melebihi 1000 °C bagi serbuk pelopor yang disediakan dengan menggunakan surfaktan. Sifat penguraian terma ini dipengaruhi oleh suhu pengeringan serbuk pelopor tersebut dan berat molekul agen kimia. Pembentukan fasa tunggal perovskit LSC telah disahkan dalam serbuk pelopor yang disediakan dengan menggunakan agen serakan, iaitu karbon teraktif dan agen pempolimeran, iaitu etilena glikol selepas serbuk pelopor tersebut dikalsin pada suhu 900 °C. Sebaliknya, fasa tunggal perovskit LSC tidak terbentuk secara lengkap dalam serbuk pelopor yang disediakan dengan menggunakan surfaktan (polietilena glikol, Triton-X-100, Brij-97 dan Tween-80) walaupun selepas serbuk pelopor tersebut telah dikalsin pada suhu yang lebih tinggi iaitu 1100 °C. Kepekatan surfaktan, nisbah molar surfaktan kepada logam kation dan nilai pH larutan bahan pelopor yang tidak sesuai telah menyumbang kepada keputusan tersebut.

Kata kunci: Agen kimia; pembentukan fasa; penguraian terma; sel fuel oksida pepejal; sol-gel

ABSTRACT

The thermal decomposition and phase formation behaviors of lanthanum strontium cobalt oxide, La_0.6Sr_0.4CoO_3-δ (LSC) material prepared by sol-gel method assisted with different chemical agent namely dispersing agent, polymerizing agent and surface-active agent or surfactant were systematically characterized through thermogravimetric (TG) and X-ray diffraction (XRD) analysis. Thermal decomposition of unwanted organic and inorganic compounds in the precursor powder of LSC material completed at temperature below than 1000 °C for the precursor powder prepared using dispersing and polymerizing agents, and at temperature above than 1000 °C for the precursor powder prepared using surfactant. The thermal decomposition behavior was influenced by the drying temperature of the prepared precursor powder and molecular weight of the chemical agent. Formation of single LSC perovskite phase was confirmed in the precursor powder prepared using dispersant, namely activated carbon and polymerizing agent, namely ethylene glycol after the precursor powder was calcined at 900 °C. Conversely, single LSC perovskite phase did not completely form in the precursor powder prepared using surfactant (polyethylene glycol, Triton-X-100, Brij-97 dan Tween-80) even after it was calcined at a higher temperature which is 1100 °C. Unsuitable surfactant concentration, molar ratio of surfactant to metal cation and precursor material solution pH value might contribute to the results.

Keywords: Chemical agent; phase formation; solid oxide fuel cell; sol-gel; thermal decomposition

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*Corresponding author; email: mahen@ukm.edu.my