Iron oxide-based catalysts for low-temperature selective catalytic reduction of NOxwith NH3

Abstract Selective catalytic reduction (SCR) is now an established NO x removal technology for industrial flue gas as well as for diesel engine exhaust gas. However, it is still a big challenge to develop a novel low-temperature catalyst for NH 3 -SCR of NO x , especially at a temperature below 200°C. In the past few years, many studies have demonstrated the potential of iron (Fe)-based catalysts as low-temperature catalysts for NH 3 -SCR of NO x . Herein, we summarize the recent progress and performance of Fe-based catalysts for low-temperature NH 3 -SCR of NO x . Catalysts are divided into three categories: single Fe x O y , Fe-based multimetal oxide, and Fe-based multimetal oxide with support catalysts. The catalytic activity and selectivity of Fe-based catalysts are systematically analyzed and summarized in light of some key factors such as activation energy, specific surface area, morphology, crystallinity, preparation method and precursor, acid sites, calcination temperature, other metal dopant/substitute, and redox property of catalysts. In addition, H 2 O/SO 2 tolerance and the NH 3 -SCR reaction mechanism over Fe-based catalysts, including Eley-Rideal and Langmuir-Hinshelwood mechanism, are emphasized. Lastly, the perspectives and future research directions of low-temperature NH 3 -SCR of NO x are also proposed.