The Temperature-Programmed Desorption of H2 from Cu/ZrO2

The desorption kinetics of hydrogen from a polycrystalline Cu/ZrO2 catalyst was investigated under atmospheric pressure using temperature-programmed desorption (TPD) experiments in a microreactor set-up. Different heating rates were applied under equal conditions with a carefully reduced catalyst. The hydrogen TPD peaks were symmetric and centered slightly above 300 K indicating associative desorption of H-2 from metallic Cu. Using heating rate variation, the kinetic parameters and were determined to be 1.24 x 10(9) s(-1) and 68 kJ mol(-1), respectively. As the modeling with constant values of and yielded signals which were too narrow, dependence of on coverage was introduced applying . By application of the "full-analysis" method an optimal fit to the experimental data was found. Setting n = 1 resulted in the best fit and a value of 61 kJ mol(-1) - (6.25 kJ mol(-1) x ) for was determined.