954
N. Jiang et al. / Catalysis Communications 12 (2011) 951–954
by secondary growth method. Seeding the millimeter-sized core
catalyst by a self-assembly method with an organic linker effectively
conduce to the formation of an integrated Silicalite-1 zeolite shell.
Light alkenes direct synthesis via FTS reaction was used to test the
catalytic performance of this zeolite capsule catalyst. In FTS reaction,
this capsule catalyst gave excellent ability for higher light alkenes
2
direct synthesis than that of the naked Fe/SiO catalyst. Benefiting
from the special confined structure and shape selectivity function, this
zeolite capsule catalyst can realize the controlled direct synthesis of
light alkenes with lower selectivity on heavy hydrocarbons. The
preparation and application of zeolite capsule catalyst in this report
also have widely potential applications, both in zeolite membrane
synthesis and multifunctional catalyst design for consecutive reaction.
Acknowledgments
Fig. 5. The selectivity of C 2= –4 in C
zeolite capsule catalyst Fe/SiO -S respectively as a function of reaction time.
2
(n≤4) hydrocarbons on the bare Fe/SiO catalyst and
The authors gratefully acknowledge the financial support of
Innovation Project of Institute of Process Engineering, Chinese
Academy of Sciences (082702), Knowledge Innovation Program of
the Chinese Academy of Science, China National 863 Program (Grant
No. 2007AA05Z137), Program for Liaoning Excellent Talents in
University (Grant no. LR201008) and Universities Science and
Research Project of Liaoning Province Education Department (Grant
no. 2009S019).
n
2
capsule catalyst, and the results showed that the CO conversion,
methane and CO selectivity were all stable without obvious
2
deactivation after entering the steady state.
All these results should be attributed to the special core-shell
structure of zeolite capsule catalyst. The Silicalite-1 zeolite shell of
2
zeolite capsule catalyst Fe/SiO -S plays multifunction in FTS reaction:
adjusting the CO concentration in core catalyst; sieving FTS products
with different size and shape; and prohibiting the re-adsorption of
light alkenes. In FTS reaction on this zeolite capsule catalyst, the
Silicalite-1 zeolite shell can reduce the diffusion rate of CO obviously
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2
A novel zeolite capsule catalyst with a specific Core (Fe/SiO )-Shell
(
Silicalite-1 zeolite membrane) structure was successfully prepared