Fe-based zeolites are known for desired high-temperature activity in the selective catalytic reduction of NO_x by NH₃, and species-performance relationships over Fe-ZSM-5 were systematically investigated in this study. Via activity tests, characterization and TOF calculation, it was found that both the relative amount and the real content of active Fe species played vital roles in the catalytic activity. The weakened high-temperature acid sites and stronger NH₃ oxidation caused by oligomeric Fe and Fe_xO_y species could account for the decreased high-temperature activity over Fe-ZSM-5 with a high Fe loading. N₂O formation via nitrate decomposition was barely found over Fe-ZSM-5 with Fe content of 1.0 wt%, the “L-H” and “E-R” pathway could coexist in the SCR reaction as suggested by DRIFT studies. DFT calculation showed that [Fe-NO₂]-1 was the most easily generated and the formation of [Fe-NO₂]-1/[FeO-NO] was the rate limiting step in the calculated reaction pathways of NO₂ and NH₃.

已知Fe基沸石在NH ₃选择性催化还原NO _x方面具有所需的高温活性，并且在这项研究中系统地研究了与Fe-ZSM-5的物种-性能关系。通过活性测试，表征和TOF计算，发现活性铁物种的相对含量和实际含量在催化活性中都起着至关重要的作用。低聚的Fe和Fe _x O _y物种引起的高温酸性位弱和NH ₃氧化更强，可以解释高Fe负载下Fe-ZSM-5的高温活性降低。N ₂Fe-ZSM-5的Fe含量为1.0 wt％时几乎没有发现通过硝酸盐分解而形成O的现象，正如DRIFT研究表明的那样，“ LH”和“ ER”途径可以共存于SCR反应中。DFT计算表明，[Fe-NO ₂ ] -1是最容易生成的，[Fe-NO ₂ ] -1 / [FeO-NO]的形成是计算出的NO ₂和NH反应路径中的限速步骤。₃。