The high mineral containing solid waste materials (SMR) generated during aluminum production currently lacks any practical application. In this work, the potential of SMR with/without additional nickel loading was investigated as an active catalyst for low temperature ammonia decomposition to produce high purity hydrogen. The XRD analysis of the samples reveals that iron oxide is the primary component of SMR with the ability to catalyze the ammonia decomposition reaction. The reducibility, metal support interaction and catalytic activity of the Ni-SMR catalysts were correlated by the reduction kinetics of the catalysts H2-TPR data and nucleation/nuclei growth models. Based on the statistical indicators, it is concluded that the random nucleation model describes catalyst reduction adequately. The estimated activation energy for the reduction of the SMR is significantly higher (108.5 kJ/mol) than that of 10Ni-SMR catalysts (86.6 kJ/mol). The increase in nickel loading also slightly decreases the activation energy of catalyst reduction, indicating an improvement in the reducibility of the nickel-containing catalysts. These reduction behaviors also reflected in the ammonia decomposition reaction in a flow reactor. The addition of nickel onto the SMR resulted in the creation of additional active nickel sites. Consequently, the nickel loaded SMR catalysts exhibited significant improvements in ammonia decomposition activity. Among the three Ni-SMR catalysts, 15Ni-SMR displayed highest activity which was consistent in extended period of reactions, indicating the catalyst stability which was further confirmed by comparing the XRD patterns of the fresh and spent catalyst.
