The detailed kinetics of the adsorption of hydrogen on polycrystalline copper studied by reactive frontal chromatography

The coverage-dependent sticking probabilities of molecular hydrogen on poly crystalline copper supported on alumina have been determined in the tempera ture range 213-273 K by analysis of the hydrogen frontal adsorption line sh ape. In this temperature range the initial sticking probabilities increase from 8x 10(-13) (213 K) to 1.3x 10(-10) (273 K). The overall activation ene rgy to adsorption has been found to be 42 kJ mol(-1). The application of re active frontal chromatography for the measurement of hydrogen sticking prob abilities on copper is a novel variant of the N2O reactive frontal chromato graphic method, developed for the measurement of copper surface areas. Its use here shows that reactive frontal chromatography may be applied generall y to any adsorbate/adsorbent system involving activated adsorption and low sticking probabilities.