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Magnetic Fe 3 O 4 @SiO 2 /Pd and Fe 3 O 4 @SiO 2 /Pd‐M (M=Ag, Cu and Zn) Catalysts for Selective Hydrogenation of Phenylacetylene
Author(s) -
Yang Lei,
Chen Xiangling,
Zhou Zhiming,
Zhang Rui,
Li Li,
Cheng Zhenmin,
Fang Xiangchen
Publication year - 2016
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201601422
Subject(s) - bimetallic strip , catalysis , phenylacetylene , selectivity , chemisorption , physisorption , materials science , sulfidation , particle size , inorganic chemistry , styrene , high resolution transmission electron microscopy , palladium , chemistry , nuclear chemistry , analytical chemistry (journal) , nanotechnology , transmission electron microscopy , biochemistry , polymer , chromatography , copolymer , composite material
Abstract Magnetic core‐shell monometallic Fe 3 O 4 @SiO 2 /Pd and bimetallic Fe 3 O 4 @SiO 2 /Pd−M (M=Ag, Cu and Zn) catalysts with low Pd loading were prepared using a modified Stöber method followed by an ion‐exchange technique, and applied to the selective hydrogenation of phenylacetylene. The structure and magnetism of the catalysts were investigated using N 2 physisorption, XRD, FT‐IR, ICP‐OES, H 2 ‐TPR, CO chemisorption, DRIFTS, HRTEM and vibrating sample magnetometer. The characterization results showed that the magnetic catalyst had smaller Pd particle size than the non‐magnetic catalyst; the thinner the silica shell of the magnetic catalyst, the stronger the magnetic intensity and hence the smaller the Pd particle size; the PdM alloy was formed for bimetallic catalysts and geometric and electronic effects occur. By comparing the activity and selectivity of different catalysts, it was found that the catalyst with smaller Pd particle size generally exhibited a higher apparent activity and selectivity to styrene but a lower specific activity, demonstrating the structure‐sensitive catalytic activity for selective hydrogenation of phenylacetylene on the magnetic Pd supported catalysts. In addition, all the bimetallic catalysts displayed higher selectivity but lower activity than the monometallic catalysts as a result of the presence of the PdM alloy. In particular, a Fe 3 O 4 @SiO 2 /Pd−Zn catalyst with the shell thickness of about 80 nm and the Pd and Zn loadings of 0.31 and 1.79 wt%, respectively, showed the best selectivity to styrene, being 86.1 % at above 99.5 % conversion of phenylacetylene. Furthermore, this catalyst maintained its activity and selectivity even after being reused ten times.