Mechanistic insight into the influence of O2 on N2O formation in the selective catalytic reduction of NO with NH3 over Pd/CeO2 catalyst. Issue 5 (23rd February 2021)

• Record Type: Journal Article
• Authors: Sheng, Liping; Li, Songda; Ma, Zhaoxia; Wang, Fei; He, Hu; Gao, Yi; Zhu, Beien; Wang, Yong; Yang, Hangsheng
• Is Part Of: Catalysis science & technology. Volume 11:Issue 5(2021)
• Page Start: 1709
• Page End: 1716
• Publication Date: 2021-02-23
• Subjects: Catalysis -- Periodicals; 541.395
• DOI: 10.1039/d0cy02325f
• Languages: English
• ISSNs: 2044-4753

Abstract

Abstract : O2 greatly affected the pathway for NO reduction over the Pd/CeO2 catalyst and resulted in a temperature-dependent NH3 -SCR performance and formation of N2 O. Abstract : Noble metal nanoparticles supported on metal oxides have been extensively investigated as potential selective catalytic reduction (SCR) catalysts to control NO X emissions, but suffer from the formation of N2 O. Herein, the N2 O formation mechanism during the NH3 -SCR process over the Pd/CeO2 catalyst was investigated by both experimental methods and density functional theory calculations. Our results revealed that O2 greatly affected the pathway for NO reduction, which resulted in a temperature-dependent SCR performance and N2 O formation. At a temperature below 175 °C, fast-SCR was the main reaction route for NO removal, which was attributed to the spontaneous oxidation of NO to NO2 . In the temperature range of 175–250 °C, the activation of NH3 facilitated the reduction of NO through standard-SCR, which promoted the removal of NO but also induced the formation of N2 O. At a temperature above 250 °C, NH3 was severely deep oxidized, which induced the formation of excess N2 O in the presence of even a low amount of O2 of 1 vol%.