Fe-β催化分解N_2O的高温稳定性及其再生性能

High Temperature Stability and Regeneration of Fe-Modified β Molecular Sieve Catalyst for Decomposition of N_2O

考察了铁改性的β分子筛(Fe-β)催化剂用于N2O分解的高温稳定性及其再生性能,在固定床反应器上对高温处理前后的Fe-β催化剂进行了评价,并对其进行了XRD、N2吸附-脱附、FTIR、H2-TPR和XPS等表征。实验结果表明,高温处理使Fe-β催化剂的活性出现不同程度的降低,但分子筛的主要晶型结构没有明显变化,催化剂活性降低的主要原因是催化剂的活性中心三价铁物种转变为活性差的铁的氧化物;另外,部分铁的氧化物向载体表面迁移聚集,活性中心的分散度降低,活性铁物种的比表面积下降,也使催化剂的活性降低。通过H2还原再生,可使Fe-β催化剂的活性基本恢复。

Fe-modified β molecular sieve（Fe-β） catalysts treated at high temperature were characterized by means of XRD, N2 adsorption-desorption, FTIR, H2-TPR and XPS, and their catalytic performances in the decomposition of N2O were studied. The treated Fe-β catalysts still kept their original crystal structure. The catalytic activity of the treated Fe-β catalysts decreased due to the transition of the active sites（ferric ions）into inactive iron oxides. In addition, part of the iron oxides migrated to the molecular sieve surface and aggregated, which led to the decrease of the dispersion and surface area of the active sites. The regeneration of the catalysts indicates that the activity of the deactivated Fe-β catalysts can be recovered basically by reduction in H2 atmosphere.