The sorption of hydrogen and other gases by evaporated iron films

Abstract

The sorption of hydrogen, carbon monoxide and nitrogen on evaporated iron films has been investigated. Sorption equilibrium was attained with hydrogen above 140°K and with nitrogen between 78 and 90° K, and heats of sorption have been evaluated. With carbon monoxide, true equilibrium values were not experimentally obtainable. All the results are consistent with the conclusion that the sorption of these gases is substantially confined to the surface and that absorption, or solution, contributes to a very small extent to the total uptake of gas. The effect of presintering at higher temperatures, in addition to reducing the surface area, is to narrow, in a symmetrical manner, the linear distribution of sites of different adsorption potential. The evaluation of the surface areas from chemisorption data is critically discussed.