Enhancing effect of Cu and Sn doping on low-temperature catalytic activity and operating temperature window of γ-Fe 2 O 3 in NH 3 -SCR of NOx

• Published in: New journal of chemistry 2024-08, Vol.48 (31), p.13957-13966
• Main Authors: Wang, Xiaobo, Zhang, Xiaoxue, Guo, Ning, Cao, Xiaojie, Liu, Jingliang, Gui, Keting
• Format: Article
• Language: English
• ISSN: 1144-0546; 1369-9261
• DOI: 10.1039/D4NJ02320J

γ-Fe 2 O 3 and Cu/Sn doped γ-Fe 2 O 3 catalysts were prepared and applied for the NH 3 -SCR of NOx. It is discovered that doping γ-Fe 2 O 3 with Cu or Sn can promote its low-temperature catalytic performance and H 2 O + SO 2 resistance. In a broad temperature range of 150–330 °C, over 80% denitration efficiency can be obtained with Cu/γ-Fe, which has the best low-temperature catalytic performance. These catalysts were characterized by many characterization techniques including BET, SEM, XRD, Raman, NH 3 -TPD, H 2 -TPR, XPS, and in situ DRIFT. The results indicate that the doping of Cu and Sn can enlarge the specific surface area while not changing the crystal structure of the catalysts. Among these catalysts, Cu/γ-Fe exhibits the strongest surface acidity and low-temperature redox capacity. Furthermore, Cu/γ-Fe possesses the highest concentration of Fe 3+ and surface chemisorbed oxygen, which enhances the NO oxidation to NO 2 . All of the mentioned above factors will facilitate its superior low-temperature catalytic activity. Finally, the E–R reaction route is mostly followed by γ-Fe 2 O 3 , while both the E–R and L–H reaction routes are obeyed by Cu/γ-Fe and Sn/γ-Fe.