Hazardous solid waste e.g., barium slag (BS) can be transformed into highly efficient molecular sieve catalysts. However, catalyst deactivation caused by SO2 poisoning remains a critical scientific challenge that requires urgent attention. Herein, V/Fe/BS-ZSM-5 molecular sieves have been devised for the NH3-SCR for NO removal reaction, showing improved SO2 resistance. This protection includes a two-step protection process: first, Ba2+ acts as a sacrificial agent by reacting with SO2, and subsequently, the resulting BaSO4 layer serves as a physical barrier. A range of advanced characterization methods (e.g., H2-TPR, NH3-TPD, TG, and in situ DRIFTS spectroscopy) were employed to gain a more comprehensive understanding of the catalyst's resistance to sulfur poisoning and its underlying reduction mechanism. The results demonstrate that the VFBZx catalysts possess remarkable resistance to SO2 and maintain stable catalytic performance, which can be ascribed to a dual-protection mechanism. The incorporation of Ba2+ significantly inhibits how SO2 moves through the catalyst, thus restricting sulfation to the catalyst layers. Subsequently, the BaSO4 coating acts as an additional protective barrier on the catalyst surface, suppressing SO2 adsorption and preventing the active metal sites (V5+-Ov-Fe3+ interfacial sites) from being poisoned. This material is expected to effectively convert BS into high-value zeolite materials through a simple synthesis method, showing promising commercial potential.
Wu et al. (2026) studied this question.