Spectroscopic Study of Absorbed CO at Polycrystallne Copper in Aqueous Phosphate Buffered Solution

Jumat Salimon, (2006) Spectroscopic Study of Absorbed CO at Polycrystallne Copper in Aqueous Phosphate Buffered Solution. Malaysian Journal of Analytical Sciences, 10 (1). pp. 27-34. ISSN 13942506

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Affiliations

Universiti Kebangsaan Malaysia, Faculty of Chemical Sciences & Food Technology

Abstract

Abstract - The behavior of adsorbed CO at polycrystalline copper surface was investigated by infrared spectroscopy. It was found that the linear adsorbed CO, Cu-COL was a dominant species on copper surface at low CO concentration. Cu-COL was electrochemically converted to bridge bonded CO, Cu-COB at high CO concentration. Increasing the CO surface coverage, θCO will increase the formation of adsorbed bridge bonded CO. N2 purging treatment was used to examine the stability of the adsorbed CO through the evacuation process. The Cu-COB remained intact while Cu-COL was completely removed from the copper surface. It suggests that Cu-COL may involve in a weak bonding to a copper surface such as in a physisorbed interaction, while Cu-COB consists much stronger bonding such as a chemisorbed interaction. The N2 purging treatment also gave an additional proof that Cu-COB was partly converted to copper(I)-carbonyl, Cu(I)-CO at anodic potential regions.

CO terjerap di atas permukaan tembaga polikristal telah dikaji dengan spektroskopi inframerah. Hasil kajian menunjukkan pada kepekatan CO yang rendah CO terjerap secara linear, Cu-COL merupakan species yang dominan. Cu-COL bertukar secara elektrokimia ke bentuk CO terjerap secara jambatan, Cu-COB pada kepekatan CO yang tinggi. Penambahan penurapan permukaan CO, θCO akan menambahkan kadar pembentukan CO terjerap secara jambatan. Kestabilan CO terjerap telah diuji secara pengolahan penyahjerapan melalui proses alih tukar gas N2. Cu-COB didapati masih kekal sementara Cu-COL telah tersingkir keseluruhannya dari permukaan tembaga. Ini mencadangkan bahawa pembentukan Cu-COL melibatkan ikatan secara lemah ke atas permukaan tembaga seperti jerapan fizik, manakala Cu-COB terlibat dengan ikatan yang kuat seperti jerapan kimia. Pengolahan alih tukar gas N2 telah memberikan bukti tambahan Cu-COB telah tertukar ke bentuk tembaga(I) karbonil, Cu(I)-CO pada julat keupayaan anodik.

Item Type:

Journal

Additional Information:

The author would like to thank UKM-Malaysia for financial support Dr. M. Kalaji (U. Wales, Bangor, UK) and Dr. R.J. Nichol (U. Liverpool, UK) for useful discussions.

Keywords:

Adsorbed carbon monoxide, polycrystalline copper, FTIR

Subjects:

Q Science

ID Code:

1067