In situ DRIFTS studies on MnO x nanowires supported by activated semi-coke for low temperature selective catalytic reduction of NO x with NH 3

Abstract

To mitigate the threat of NO x on the environment, MnO x nanowires were fabricated on activated semi-coke (MnO x NW/ASC) for the first time. The prepared MnO x NW/ASC was used for the low temperature selective catalytic reduction (SCR) of NO x with NH 3 , which achieved an efficiency of over 90% with a low loading content of 1.64 wt% at 150-210 °C. This high performance could be ascribed to synergistic effect between MnO x and ASC. Specifically, the large specific surface area and reducible property of ASC facilitated the dispersion of MnO x and the formation of Mn 3+ , respectively. Meanwhile, MnO x nanowires provided more redox sites and lattice oxygen species due to the coexistence of Mn 3+ and Mn 4+ , which accelerated the catalytic cycle. The in situ DRIFTS studies revealed that ASC was conducive to the adsorption of NO and NH 3 . Most importantly, the existence of Mn 3+ favored the formation of amide species and the subsequent reduction reaction. Furthermore, the Langmuir-Hinshelwood (L-H) route between coordinated NH 3 and bidentate nitrate was predominating in the SCR process and responsible for the high catalytic activity at low temperature.