N2O Catalytic Decomposition and NH3-SCR Coupling Reactions over Fe-SSZ-13 Catalyst: Mechanisms and Interactions Unraveling via Experiments and DFT Calculations

Abstract

Simultaneous catalytic elimination of NO and N2O from exhausts is an ideal solution for nitric or adipic acid plants. Herein, Fe-based zeolite catalysts were applied for the NH3–NOx–N2O system. 1% Fe-SSZ-13 performed excellent catalytic activity with 100% conversions for both NOx and N2O at 400–600 °C. Experimental and computational research studies unraveled that NO could significantly improve N2O decomposition by reacting with αO* to generate easily desorbed NO2; furthermore, NO−αO* also can decrease charge density of Fe−αO*, facilitating αO* desorbed from the Fe sites. Besides, NH3 inhibits low-temperature deN2O activity due to strong competitive adsorption with N2O; however, NH3 accelerates N2O decomposition by consuming αO* and simultaneously reduces N2O as a reductant at high temperature. Interestingly, the αO* generated from N2O decomposition would enhance NO oxidation to NO2, which is beneficial to NH3-selective catalytic reduction. This work elaborates fundamental insights for simultaneous abatement of NOx and N2O and provides candidate catalyst for application.