Iron-Based Alumina-Supported Catalysts for Clean Hydrogen Production from Ammonia

This work presents the potential of various iron-based catalysts, with an iron content between 10 and 30 wt%, supported on alumina that were explored for pure hydrogen production from ammonia decomposition reaction. The X-ray diffraction (XRD) results indicated that major diffraction peaks associated with the alumina support and iron oxide were found along with fractions of iron aluminate. The reduction profiles from temperature-programmed reduction (TPR) showed that the extent of reduction, number of reducible species, and iron oxide interaction with alumina varied with an increase in iron oxide content, from 10 to 30 wt%, such that an increase in iron oxide loading promoted easier reduction, enhanced reducibility, and improved number of reducible species. Temperature-programmed desorption profiles using hydrogen and nitrogen showed that an increase in iron content increased the amount of hydrogen desorbed; however, nitrogen desorption exhibited a decreasing trend. These factors influenced catalytic activity results and an increase in iron content increased the ammonia conversion. Kinetic data also showed that a higher iron content (30 wt%) demonstrated the lowest apparent activation energy of 48.2 kJ/mol.