Promotion of Ilmenite Blending on the Antisulfur Performance of the Lithium-Silicon-Powder-Derived Low-Temperature NH3-SCR Catalyst

Lithium-silicon-powder waste, combined with ferromanganese ore (MnFe/Z), shows great promise as a cost-effective low-temperature NH3-SCR catalyst for NOx emission control. However, the MnFe/Z catalyst's low sulfur tolerance limits its applications. A natural ilmenite (NI)-doped catalyst (NIx-MnFe/Z) was carefully studied and optimized to address this deficiency. The results revealed that natural ilmenite doping enhanced MnFe/Z's antisulfur performance without negatively affecting catalytic activity in the low-temperature range (125-200 degrees C). The optimized NI3-MnFe/Z had the best catalytic activity, maintaining 96.5% NO conversion after 6 h under 50 ppm of SO2 at 175 degrees C. The introduced NI suppressed the electron transfer from Mn4+ and Fe3+ to SO2 and reduced sulfate formation, effectively protecting the active sites from SO2 poisoning. NI addition protected the redox properties of Mn and Fe and the acidity of the catalyst; the NI3-MnFe/Z catalyst broke the SO2 poisoning obstacles in low-temperature NH3-SCR toward future application for efficient NO elimination from industrial flue gas.