Sains Malaysiana 36(1): 27-32 (2007)

 

 

Adsorbed CO at Polycrystalline Copper in Phosphate Buffered Solution

(CO Terjerap dipermukaan Kuprum Polihablur dalam Larutan Tampan Fosfat)

 

 

Jumat Salimon

Pusat Pengajian Sains Kimia dan Teknologi Makanan

Fakulti Sains dan Teknologi, Universiti Kebangsaan Malaysia

43600 UKM Bangi Selangor D.E. Malaysia

  

AbstraCT

The adsorption of CO at polycrystalline copper surface was investigated spectroscopically.   It  was  found  that  CO adsorbed  as  a linear adsorbed CO, Cu-COL and was a dominant species on copper surface at low CO concentration.   A Cu-COL was electrochemically converted to a bridge bonded CO, Cu-COB at a high CO concentration condition.  Increasing the CO surface coverage, qCO will increase the formation of adsorbed bridge bonded CO.  A nitrogen gas purging treatment was used to examine the stability of an adsorbed CO through the evacuation process.  The result showed that 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 prove that Cu-COB was partly converted to Cu(I)-CO at anodic potential regions.

 

Keywords: Adsorbed carbon monoxide; copper surface

 

AbsTRAK

 

Penjerapan CO di atas permukaan polihablur kuprum telah dikaji melalui sifat spektroskopiknya.  Didapati CO yang terjerap wujud dalam bentuk CO terjerap linear, Cu-COL dan merupakan bentuk CO terjerap yang dominan pada kepekatan CO yang rendah.  Cu-COL bertukar secara elektro-kimia ke bentuk CO terjerap secara jambatan, Cu-COB pada kepekatan CO yang tinggi.   Penambahan penurapan permukaan CO, qCO akan menambahkan kadar pembentukan CO terjerap secara jambatan.  Kestabilan CO terjerap telah diuji secara pengolahan penyahjerapan melalui proses alih tukar gas nitrogen.  Hasil kajian menunjukkan bahawa Cu-COB didapati masih kekal manakala Cu-COL telah terkeluar keseluruhannya dari permukaan kuprum.   Ini mencadangkan bahawa pembentukan Cu-COL melibatkan ikatan secara lemah ke atas permukaan kuprum seperti jerapan fizik, sementara Cu-COB terlibat dengan ikatan yang kuat seperti jerapan kimia.   Pengolahan alih tukar gas nitrogen juga memberi bukti tambahan bahawa sebahagian Cu-COB telah bertukar kebentuk kuprum(I) karbonil, Cu(I)-CO pada julat keupayaan anodik.

 

Kata kunci: Karbon monoksida terjerap; permukaan kuprum

 

 

RUJUKAN/REFERENCES

 

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