A stepwise loading method to magnetically responsive Pt-Fe(3)O(4)/MCNT catalysts for selective hydrogenation of 3-methylcrotonaldehyde

Pt-loaded multi-walled carbon nanotubes (Pt/MCNTs) and magnetically responsive Pt-Fe(3)O(4)/MCNT catalysts were prepared by a stepwise loading of preformed Pt and Fe(3)O(4) nanoparticles onto multi-walled carbon nanotubes (MCNTs). The structure, composition, and magnetism of the catalysts were characterized by X-ray diffraction (XRD), TEM, H(2)-O(2) 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-Fe(3)O(4)/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-Fe(3)O(4)/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-Fe(3)O(4)/MCNT catalysts show a good recyclability, confirmed by five cycles of reusage. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/1556-276X-9-677) contains supplementary material, which is available to authorized users.