THE INTERACTION OF H-2 AND N2 WITH IRON CATALYSTS USED FOR NH3 SYNTHESIS - A TEMPERATURE-PROGRAMMED DESORPTION AND REACTION STUDY

Iron catalysts with and without potassium promoter were investigated in a flow reactor system connected to a mass spectrometer. Temperature-programmed surface reaction (TPSR) of preadsorbed dissociated nitrogen with hydrogen has been studied under various experimental conditions. The results suggest that the total amount of ammonia produced gives a good estimate of the active area of the catalyst. The shape of the TPSR spectrum depends on the promoter content, the initial coverage and the partial pressure of H2 and indicates that the surface is nonuniform. The exact interpretation of the H2 TPD spectra is influenced by several complications. The evaluation of the results is aided by computer simulations. © 1993 Academic Press, Inc.