Laporan ini membincangkan pembangunan pelet bermangkin tin dioksida tulen, tin dioksida yang didopkan lantanum dan serium terhadap pengoksidaan etanol bermangkin. Serbuk tin dioksida tulen dan dop lanthanum dan serium disediakan melalui kaedah gel-sol dan dihancurkan menjadi manik berbutir. Pengkalsinan dikenakan terhadap pelet-pelet bermangkin pada suhu 400oC selama 4 jam. Pencirian struktur telah dijalankan dengan menggunakan penganalisa XRD, penganalisa luas permukaan BET dan pengimbasan electron mikroskop. Ciri-ciri pemangkin telah diuji dalam reaktor dasar padatan, jenis dopan dan suhu pengendalian dijadikan sebagai fungsi.Mekanisma pengoksidaan etanol dan hubungan antara sensor gas dan bahan pemangkin juga dikaji. Hasil analisa struktur menunjukkan bahawa dopan telah berjaya dimasukkan ke dalam kekisi hablur SnO2. Analisis physiochemical serbuk menunjukkan bahawa purata saiz kristal dikurangkan manakala luas permukaan bertambah dengan penambahan dopan, terutamanya dopan serium. Prestasi pengoksidaan bermangkin menunjukkan bahawa penukaran etanol dipertingkatkan dengan penambahan pendopan. Ce- SnO2 mempamerkan penukaran etanol yang tinggi walaupun pada 200oC di mana sampel pemangkin lain mempunyai penukaran yang sangat rendah pada suhu tertentu . La- SnO2 menunjukkan reaksi lambat pada suhu yang rendah dan aktiviti pemangkin tinggi bermula dari 300oC . Serium didopkan SnO2 adalah bahan pemangkin yang paling menjanjikan untuk aplikasi sensor gas kerana hablur yang kecil , luas permukaan BET tinggi dan penukaran etanol bermangkin yang tinggi.
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This report describes the development of pure, lanthanum and cerium doped tin dioxide catalytic pellet in catalytic ethanol oxidation. Pure, lanthanum and cerium doped tin dioxide powders were prepared by sol-gel method and crushed into granular beads. Calcination at 400oC was carried out for 4 hours to the catalytic pellet. Structural characterization was performed using X-ray Diffraction (XRD), BET Surface Analysis and Scanning Electron Microscope (SEM). Catalytic properties were tested in packed bed reactor, as a function of type of additive and operating temperature. The ethanol oxidation mechanism and relationship between gas sensor and catalytic material were also studied. The structural analysis showed that the dopant have been successfully incorporated into the tin dioxide crystal lattice. The physiochemical analysis indicated that the average crystallite size was reduced while BET surface area was increased by the addition of dopant particularly Cerium. The catalytic oxidation performance revealed that the conversion of ethanol is enhanced by the addition of dopant. Ce-SnO2 exhibited high ethanol conversion even at 200oC where other catalyst samples have extremely low conversion at this particular temperature. La-SnO2 exhibited a delayed reaction at the low temperature and high catalytic activity starting from 300oC. Cerium doped SnO2 is the most promising catalytic material for gas sensor application due to its low crystallite size, high BET surface area and high catalytic conversion of ethanol.
Synthesis, characterization and catalytic performance of mesoporous SnO2 for gas sensor application / Teh Derbin