Gold nanoparticles decorated on Bingel-thiol functionalized multiwall carbon nanotubes as an efficient and robust catalyst

Multiwall carbon nanotubes (MWCNT) functionalized with bidentate thiol groups have been prepared through Bingel reaction followed by amidation of the malonyl ester groups with cysteamine. This material acted as a convenient support for the in situ deposition of gold nanoparticles. Chemical and structural characterization of the materials was performed by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy, confirming the retention of the intrinsic carbon nanotube structural properties and the deposition of spherical gold nanoparticles (AuNPs) with diameters of 4 +/- 1 nm. This nanohybrid showed to be a highly active and robust catalyst on the total reduction of 4-nitrophenol in the presence of NaBH4, showing a rate constant of k = 0,436 min(-1), with no loss of catalytic activity after six reutilization cycles. Control materials prepared by direct immobilization of Au nanoparticles onto pristine carbon nanotubes and on Bingel functionalized MWCNT material led to lower Au loading or afforded less stable catalysts, resulting in significantly poorer catalytic activity. (C) 2014 Elsevier B.V. All rights reserved.