Utilizing red mud modified by simple treatments as a support to disperse ruthenium provides a high and stable performance for COx-free hydrogen production from ammonia

Abstract

Red mud (RM), the by-product of aluminum industry produced in vast amounts, is a hazardous waste rich in Fe2O3, an active component for various reactions. Here, we used RM modified by simple acid treatments as a support for dispersing Ru to obtain a highly efficient catalyst for ammonia decomposition. Catalytic performance measurements showed that the catalyst prepared by 5 wt.% Ru loading on modified red mud (MRM) provides 99.6% conversion at a significantly high space velocity of 240 000 cm(3) NH3 h(-1) g(cat)(-1) at 700 degrees C. XRD spectrum of the used catalyst illustrates high dispersion of Ru confirmed by the absence of Ru diffraction peaks and the formation of Fe3Ny moieties contributing to the catalytic activity. Time-on-stream measurements show that the catalyst is superior in terms of stability as it provides a stable performance for up to seven days. Data illustrated that MRM both acts as an iron nitride-based catalyst itself and as a robust support for Ru crystallites which synergistically results in a high and stable performance. Findings presented here enable the remediation of an industrial waste by utilizing RM as an almost cost-free, robust, and efficient support for Ru.