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A stepwise loading method to magnetically responsive Pt-Fe3O 4/MCNT catalysts for selective hydrogenation of 3-methylcrotonaldehyde.

Song S, Yu J, Xiao Q, Ye X, Zhong Y, Zhu W - Nanoscale Res Lett (2014)

Bottom Line: A very high selectivity to 3-methylcrotonalcohol of 98% at a conversion of about 80% was available on the magnetic Pt-Fe3O4/MCNT catalyst.The magnetic catalyst, with good superparamagnetism, can be easily recovered from the liquid phase system under the external magnetic field.Moreover, both the Pt/MCNT and magnetic Pt-Fe3O4/MCNT catalysts show a good recyclability, confirmed by five cycles of reusage.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Institute of Physical Chemistry, Zhejiang Normal University, Jinhua, 321004, People's Republic of China, 454283594@qq.com.

ABSTRACT
Pt-loaded multi-walled carbon nanotubes (Pt/MCNTs) and magnetically responsive Pt-Fe3O4/MCNT catalysts were prepared by a stepwise loading of preformed Pt and Fe3O4 nanoparticles onto multi-walled carbon nanotubes (MCNTs). The structure, composition, and magnetism of the catalysts were characterized by X-ray diffraction (XRD), TEM, H2-O2 titration, inductively coupling plasma-atomic emission spectroscopy (ICP-AES), and superconducting quantum interference device (SQUID) techniques. Ascribed to the well-controlled particle size in the preformed Pt colloids, Pt particles in the consequent Pt/MCNT and Pt-Fe3O4/MCNT catalysts are of high uniformity and dispersion. The prepared Pt catalysts show an excellent catalytic performance in the liquid phase hydrogenation of 3-methylcrotonaldehyde, one of typical α,β-unsaturated aldehydes. A very high selectivity to 3-methylcrotonalcohol of 98% at a conversion of about 80% was available on the magnetic Pt-Fe3O4/MCNT catalyst. The magnetic catalyst, with good superparamagnetism, can be easily recovered from the liquid phase system under the external magnetic field. Moreover, both the Pt/MCNT and magnetic Pt-Fe3O4/MCNT catalysts show a good recyclability, confirmed by five cycles of reusage.

No MeSH data available.


Magnetization curves of (a) 5Fe3O4/MCNT, (b) 3Pt-1Fe3O4/MCNT, (c) 3Pt-5Fe3O4/MCNT, (d) five-cycles-used 3Pt-5Fe3O4/MCNT, and (e) 3Pt-10Fe3O4/MCNT. Inset: the magnification of the square circle.
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Fig7: Magnetization curves of (a) 5Fe3O4/MCNT, (b) 3Pt-1Fe3O4/MCNT, (c) 3Pt-5Fe3O4/MCNT, (d) five-cycles-used 3Pt-5Fe3O4/MCNT, and (e) 3Pt-10Fe3O4/MCNT. Inset: the magnification of the square circle.

Mentions: The magnetic properties of Fe3O4/MCNT magnetic composite and Pt-Fe3O4/MCNT magnetic catalysts were investigated by a magnetic property measurement system (MPMS) at room temperature. As shown in Figure 7, all the hysteresis loops go through the origin. Almost no remanence exists when the external magnetic field is removed (Figure 7, inset), revealing the superparamagnetism of the samples. The superparamagnetism implies that the magnetic responsive catalysts can be well redispersed in the absence of a magnetic field. The saturated magnetization value of 5Fe3O4/MCNT is about 3.6 emu·g-1. While, for 3Pt-5Fe3O4/MCNT, the value drops to 3.3 emu·g-1. Such a drop may be attributed to the decrease of the relative amount of Fe3O4 after loading with Pt. The saturated magnetization values of 3Pt-1Fe3O4/MCNT, 3Pt-5Fe3O4/MCNT, and 3Pt-10Fe3O4/MCNT are 0.8, 3.3, and 4.7 emu·g-1, respectively. The magnetization of these magnetic samples enhances with the increase of the Fe3O4 loading. The saturated magnetizations of Fe3O4 nanoparticles calculated from either Fe3O4/MCNT or Pt-Fe3O4/MCNT are 77 to 81 emu·g-1, in accordance with the values reported by Sun et al. [33]. Moreover, the magnetization curves coincide very well for the fresh- and five-cycles-used 3Pt-5Fe3O4/MCNT, indicating the good stability in magnetism.Figure 7


A stepwise loading method to magnetically responsive Pt-Fe3O 4/MCNT catalysts for selective hydrogenation of 3-methylcrotonaldehyde.

Song S, Yu J, Xiao Q, Ye X, Zhong Y, Zhu W - Nanoscale Res Lett (2014)

Magnetization curves of (a) 5Fe3O4/MCNT, (b) 3Pt-1Fe3O4/MCNT, (c) 3Pt-5Fe3O4/MCNT, (d) five-cycles-used 3Pt-5Fe3O4/MCNT, and (e) 3Pt-10Fe3O4/MCNT. Inset: the magnification of the square circle.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4493847&req=5

Fig7: Magnetization curves of (a) 5Fe3O4/MCNT, (b) 3Pt-1Fe3O4/MCNT, (c) 3Pt-5Fe3O4/MCNT, (d) five-cycles-used 3Pt-5Fe3O4/MCNT, and (e) 3Pt-10Fe3O4/MCNT. Inset: the magnification of the square circle.
Mentions: The magnetic properties of Fe3O4/MCNT magnetic composite and Pt-Fe3O4/MCNT magnetic catalysts were investigated by a magnetic property measurement system (MPMS) at room temperature. As shown in Figure 7, all the hysteresis loops go through the origin. Almost no remanence exists when the external magnetic field is removed (Figure 7, inset), revealing the superparamagnetism of the samples. The superparamagnetism implies that the magnetic responsive catalysts can be well redispersed in the absence of a magnetic field. The saturated magnetization value of 5Fe3O4/MCNT is about 3.6 emu·g-1. While, for 3Pt-5Fe3O4/MCNT, the value drops to 3.3 emu·g-1. Such a drop may be attributed to the decrease of the relative amount of Fe3O4 after loading with Pt. The saturated magnetization values of 3Pt-1Fe3O4/MCNT, 3Pt-5Fe3O4/MCNT, and 3Pt-10Fe3O4/MCNT are 0.8, 3.3, and 4.7 emu·g-1, respectively. The magnetization of these magnetic samples enhances with the increase of the Fe3O4 loading. The saturated magnetizations of Fe3O4 nanoparticles calculated from either Fe3O4/MCNT or Pt-Fe3O4/MCNT are 77 to 81 emu·g-1, in accordance with the values reported by Sun et al. [33]. Moreover, the magnetization curves coincide very well for the fresh- and five-cycles-used 3Pt-5Fe3O4/MCNT, indicating the good stability in magnetism.Figure 7

Bottom Line: A very high selectivity to 3-methylcrotonalcohol of 98% at a conversion of about 80% was available on the magnetic Pt-Fe3O4/MCNT catalyst.The magnetic catalyst, with good superparamagnetism, can be easily recovered from the liquid phase system under the external magnetic field.Moreover, both the Pt/MCNT and magnetic Pt-Fe3O4/MCNT catalysts show a good recyclability, confirmed by five cycles of reusage.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, Institute of Physical Chemistry, Zhejiang Normal University, Jinhua, 321004, People's Republic of China, 454283594@qq.com.

ABSTRACT
Pt-loaded multi-walled carbon nanotubes (Pt/MCNTs) and magnetically responsive Pt-Fe3O4/MCNT catalysts were prepared by a stepwise loading of preformed Pt and Fe3O4 nanoparticles onto multi-walled carbon nanotubes (MCNTs). The structure, composition, and magnetism of the catalysts were characterized by X-ray diffraction (XRD), TEM, H2-O2 titration, inductively coupling plasma-atomic emission spectroscopy (ICP-AES), and superconducting quantum interference device (SQUID) techniques. Ascribed to the well-controlled particle size in the preformed Pt colloids, Pt particles in the consequent Pt/MCNT and Pt-Fe3O4/MCNT catalysts are of high uniformity and dispersion. The prepared Pt catalysts show an excellent catalytic performance in the liquid phase hydrogenation of 3-methylcrotonaldehyde, one of typical α,β-unsaturated aldehydes. A very high selectivity to 3-methylcrotonalcohol of 98% at a conversion of about 80% was available on the magnetic Pt-Fe3O4/MCNT catalyst. The magnetic catalyst, with good superparamagnetism, can be easily recovered from the liquid phase system under the external magnetic field. Moreover, both the Pt/MCNT and magnetic Pt-Fe3O4/MCNT catalysts show a good recyclability, confirmed by five cycles of reusage.

No MeSH data available.