Enhanced denitrification performance of Mo/Mn co-doped 5 %Fe/TiO2 catalysts via citric acid-assisted impregnation

Abstract

This study investigates the denitrification performance of Fe5Mn3Mo3/TiO2 catalysts prepared using citric acid-assisted impregnation (CA) and conventional impregnation (IM) methods in the context of NH3-selective catalytic reduction (SCR) reaction. Specifically, the influence of citric acid quantity on the catalytic activity is studied, with a special emphasis on Fe5Mn3Mo3/TiO2-0.5CA variant. Our results demonstrate that Fe5Mn3Mo3/TiO2-0.5CA exhibits superior low-temperature activity and prolonged stability compared to the conventional impregnation method. Remarkably, operating temperature window based on 80 % denitrification activity is T80 = 190–405 °C. Furthermore, the Fe5Mn3Mo3/TiO2-0.5CA maintains a noteworthy 98 % NO conversion at 300 °C for a duration of 100 hours. The excellent performance is attributed to the highly dispersed nature of the active species, the large specific surface area, the low apparent activation energy, and a robust interaction between the active components and the substrate. XPS analysis reveals a significantly higher Oα/(Oα+Oβ) ratio for Fe5Mn3Mo3/TiO2-0.5CA, underscoring the effectiveness of citric acid modification in promoting the formation of Fe2+ species. This research provides valuable insights into the design and optimization of catalysts for efficient denitrification processes.