Oxygen chemisorption on well cleaned carbon surfaces

doi:10.1016/0008-6223(67)90052-8

Carbon

Volume 5, Issue 4, September 1967, Pages 363-371

https://doi.org/10.1016/0008-6223(67)90052-8 Get rights and content

Abstract

Graphon, a highly graphitized carbon black, was first oxidized to 14.4% weight loss in O₂ at 625°C to introduce significant active surface area. Following the cleaning of the activated Graphon surface by heating at 975°C in a vacuum of 10⁻⁸ torr, chemisorption of oxygen between 25–400°C was studied. The saturation amounts of oxygen adsorbed sharply increase at temperatures above 250°C, suggesting the presence of at least two types of active sites. The maximum amount of oxygen adsorbed is estimated to occupy 2.8 m²/g or 2.6% of the total surface. The rate of oxygen adsorption on the more active sites is given by k_oCn∞(1−θ)², where k₀ = 7.14 × 10⁹ exp (−7,400/RT) cc/sec mole O₂. Following a large number of adsorption-desorption cycles, the Graphon surface is additionally activated to yield (in part) a fraction of very active sites that are not produced at comparable burn-offs by higher temperature activation between 500–625°C.

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^∗: Present address: Dow Chemical Company, Midland, Michigan.

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Oxygen chemisorption on well cleaned carbon surfaces

Abstract

J. phys. Chem.

Quart, Rev. (London)

Rev. pure appl. Chem.

J. Chim. phys.

J. Chim. phys.

Chemisorption

Carbon

Carbon