Surface complexes on carbon—I a preliminary investigation of surface oxygen complex on a non-graphitic carbon

✍ Scribed by J. Dollimore; C.M. Freedman; B.H. Harrison; D.F. Quinn

• Publisher: Elsevier Science
• Year: 1970
• Tongue: English
• Weight: 799 KB
• Volume: 8
• Category: Article
• ISSN: 0008-6223
• DOI: 10.1016/0008-6223(70)90052-7

✦ Synopsis

A preliminary investigation has been made into the behaviour of the surface oxygen complex during its formation and thermal desorption from the cleaned surface of a non-graphitic carbon (a rapidly pyrolised 720°C polyvinylidene chloride carbon). Using a direct sampling mass spectrometric technique a reasonable agreement was obtained between the amount of oxygen chemisorbed as surface oxide (by material balance of oxygen) and that obtained from analysis of the thermal desorption products CO and COZ. The extent of the surface oxygen complex coverage was shown to be of the order of 3 per cent of the total surface. The thermal desorption products CO and CO, were found to obey separately the Elovich equation for desorption in the temperature range 400"-900°C. As a consequence of the mechanism by which thermal desorption occurred, a linear plot of increasing activation energy of desorption of CO vs. decreasing coverage 13 of the active sites was obtained. A comparison is made between the observed behaviour of surface oxide on a non-graphitic carbon and that obtained by other workers on graphitic carbons.