Red Mud as an Efficient, Stable, and Cost-Free Catalyst for COx-Free Hydrogen Production from Ammonia

Red mud, one of the mostly produced industrial wastes, was converted into a catalyst with exceptionally high and stable performance for hydrogen production from ammonia. Results showed that iron species produced after reduction of the HCl digested red mud were converted into ε-Fe2N during the induction period of ammonia decomposition reaction at 700 °C. The catalytic performance measurements indicated that the modified red mud catalyst provides a record high hydrogen production rate for a non-noble metal catalyst at this temperature. For instance, stable hydrogen production rates were measured as 72 and 196 mmol H2 min(-1) gcat(-1) for the corresponding space velocities of 72 000 and 240 000 cm(3) NH3 h(-1) gcat(-1), respectively, at 700 °C. These results offer opportunities to utilize one of the key hazardous industrial wastes as an eco-friendly, efficient, stable, and almost cost-free catalyst for COx-free hydrogen production from ammonia decomposition.