Sorption behavior of hydrogen gas and tritiated hydrogen gas on potassium-carbon intercalation compounds

Abstract

The sorption behaviors of hydrogen gas at 77 K on several different potassium-carbon intercalation compounds (KC x ) have been studied. Samples of KC x were prepared from petroleum-coke carbons heat-treated at 800, 1000, 1500 and 2300°C by the modified two-bulb method. The isotherms of hydrogen absorption and the isotropic H 2-HT partition coefficients between the absorbed phase and the gas phase determined on them were found to be considerably influenced by the composition of KC x as well as the heat-treatment temperature (HTT) of the starting carbon materials. In order to account for such behavior, which is not only different from those of ordinary compounds prepared from graphite but inconsistent with the so-called KC 8-KC 24 mixture model, a possibility is suggested that there may exist an absorptive intermediate phase between KC 8 and KC 24 in the case of KC x compounds prepared from low-HTT-carbons.