cs9b05449_si_001.pdf (1.17 MB)
Exploring the Reaction Paths in the Consecutive Fe-Based FT Catalyst–Zeolite Process for Syngas Conversion
journal contribution
posted on 2020-03-09, 14:13 authored by Xiaoli Yang, Ruifeng Wang, Jia Yang, Weixin Qian, Yaru Zhang, Xuning Li, Yanqiang Huang, Tao Zhang, De ChenDirect conversion
of syngas into aromatics with tandem catalysts
containing Fe-based Fischer–Tropsch synthesis (FTS) catalysts
and zeolites has been attracting significant attention because of
the great cost-efficiency. However, the interaction role between two
active species and reaction paths are still unclear. We report here
that a high yield of aromatics was achieved by serial reactions directly
from syngas on a Na-Fe-ZrO2/ZSM-5 tandem catalyst. Results
point out significant impacts of zeolite in the catalytic system on
performance including activity and selectivity. The role of the zeolite
on reaction pathways about both CO conversion and aromatic formation
has been systematically investigated by steady-state isotopic transient
kinetic analysis and designed experiments. The presence of zeolite
in the catalytic system promotes the CO hydrogenation rate by means
of improving the iron carburization degree, possibly because of the
enhanced CO adsorption and the formation of surface intermediates.
It also enhances selectivity to aromatics by coupling CO to participate
in the olefin transformation on ZSM-5. In addition, the formation
rate of aromatics is proportional to the number of Lewis acidic sites,
suggesting the dehydroaromatization route as the main mechanism of
olefin aromatization. These findings provide some insights into the
effect of ZSM-5 on reaction paths over the FTS catalyst–zeolite
tandem catalyst system.