Enhanced metal - support interaction through activated carbon structure optimization: New insights into enhanced NH3-SCR performance of Fe-Mn/ AC catalysts

Although activated carbon (AC) shows promise as a support material for low-temperature selective catalytic reduction (SCR) catalysts, understanding and optimizing the metal - support interaction (MSI) through structural control remains crucial for enhancing catalytic performance. This contribution demonstrates that controlled optimization of AC support structure through activation time regulation significantly enhances SCR performance via synergistic effects of micropore development, carbon defect formation, and strengthened MSI. The optimized Fe-Mn/AC-40 catalyst achieves an NO conversion of 83.0 % at 120 degrees C, representing a 139.2 % improvement over Fe-Mn/AC-0 (34.7 %). This enhancement stems from the synergistic effects of optimal microporous structure (S-mic = 275 m(2)/g), increased NO adsorption capacity (0.276 mmol/g), and enhanced metal oxide dispersion promoted by carbon defects. The carbon defects (similar to 3.0 %) serve as effective anchoring sites for metal oxides, leading to strengthened MSI as evidenced by the positive shift in reduction temperature and increased H-2 consumption. XPS analysis reveals that enhanced MSI promotes the redistribution of manganese oxidation states, with Mn3+ (24.3 %) and Mn4+ (33.1 %) surface concentrations being significantly increased. These findings provide new insights into the rational design of high-performance SCR catalysts through MSI engineering and offer a practical approach for developing cost-effective catalysts for low-temperature NOx removal applications.