Electron-microscopic investigation of the reaction of water vapor with single crystals of graphite—II. Inhibition by hydrogen

✍ Scribed by G.L Montet; G.E Myers

• Publisher: Elsevier Science
• Year: 1971
• Tongue: English
• Weight: 541 KB
• Volume: 9
• Category: Article
• ISSN: 0008-6223
• DOI: 10.1016/0008-6223(71)90090-x

✦ Synopsis

The earlier study of the graphite-water vapor reaction has been extended to the inhibition of the reaction by hydrogen. The apparatus and technique were essentially those used in the earlier study. It was found that very low concentrations of hydrogen, less than 1 vpm, inhibit the reaction to an appreciable extent. The order of the reaction with respect to hydrogen was found to be near -3, indicating that the effect is produced by a dissociative adsorption. The apparent activation energy for the reaction increases with increasing hydrogen concentration, as does the pre-exponential factor in the Arrhenius equation; thus, the inhibition exhibits the "compensation" effect. The effective concentration of the hydrogen produced in the reaction when no hydrogen is added deliberately can be calculated from the data and is found to be equivalent to about 0.1 vpm of hydrogen.