Low-temperature Fe–MnO2 nanotube catalysts for the selective catalytic reduction of NOx with NH3. Issue 19 (7th September 2021)

• Record Type: Journal Article
• Authors: Fan, Hao; Fan, Jie; Chang, Tian; Wang, Xiuru; Wang, Xin; Huang, Yu; Zhang, Yang; Shen, Zhenxing
• Is Part Of: Catalysis science & technology. Volume 11:Issue 19(2021)
• Page Start: 6553
• Page End: 6563
• Publication Date: 2021-09-07
• Subjects: Catalysis -- Periodicals; 541.395
• DOI: 10.1039/d1cy01181b
• Languages: English
• ISSNs: 2044-4753

Abstract

Abstract : Fe improved the reducibility of Mn sites and reduced the oxidizing properties of bridging oxygen. Abstract : Exhaust gas from the sintering process in the iron and steel industry contains NO x and SO2 at low temperature. Therefore, the corresponding denitration catalyst should have favorable low-temperature activity and SO2 resistance. In this study, an Fe-doped MnO2 nanotube catalyst with the (211) crystal face synthesized using a one-step hydrothermal synthesis method demonstrated favorable pore structure and many weak acidic sites, which improved its low-temperature activity (>90% at 125–225 °C), N2 selectivity (>90%), and SO2 resistance. The NO conversion rate reached 94% when the Fe0.5% MnO2 catalyst was used in the presence of SO2 . Moreover, the Fe in the Fe0.5% MnO2 catalyst improved the reducibility of the surface Mn sites and reduced the oxidizing properties of bridging oxygen, resulting in easier conversion of Mn 4+ to Mn 3+ and affecting the regeneration of oxygen vacancies in the selective catalytic reduction of NO x with NH3 process. In situ diffuse reflectance infrared spectroscopy showed that the reduction of NO x in the MnO2 nanotubes and Fe0.5% MnO2 sample involved the Eley–Rideal mechanism, whereas the NH3 -SCR process of the Fe5% MnO2 sample involved both Langmuir–Hinshelwood and Eley–Rideal mechanisms.