Manganese and manganese–molybdenum catalysts supported on SBA-15: Effect of synthesis method on structure, redox properties, and CO oxidation performance under harsh conditions

Manganese-based catalysts have emerged as cost-effective alternatives to noble-metal systems for carbon monoxide oxidation; however, their practical application is often limited by deactivation in the presence of interfering gases such as SO₂ and H₂O. In this study, SBA-15-supported Mn and Mn–Mo catalysts were prepared using incipient wetness impregnation (IM), microwave-assisted deposition–precipitation (DP), and sol–gel one-pot (OP) synthesis routes. The materials were comprehensively characterized by XRD, Raman spectroscopy, UV–Vis DRS, EPR, XPS, H₂-TPR, and TEM. Catalytic performance for CO oxidation at 730 °C was evaluated using feeds containing SO₂, H₂O, or both. Among the investigated systems, the one-pot-prepared Mn–Mo/SBA-15 catalyst exhibits a more homogeneous active-phase distribution, enhanced redox properties, and superior resistance to SO₂- and H₂O-induced deactivation compared to Mo-promoted catalysts prepared by conventional methods. These results demonstrate that integrated one-pot synthesis is a promising strategy for designing structurally robust Mn–Mo catalysts for high-temperature CO oxidation under harsh, sulfur- and steam-containing environments. • One-pot synthesis yields highly dispersed Mn–Mo species strongly interacting with SBA-15 • Mn–Mo/SBA-15 (one-pot) shows superior redox behavior and enhanced oxygen mobility • Mo promotion markedly improves catalyst resistance to SO₂, H₂O, and combined poisoning • One-pot Mn–Mo catalyst achieves the highest CO oxidation stability under harsh FCC-like feeds.