Preparation of Pt- and Pd-decorated CNTs by DCC-activated amidation and investigation of their electrocatalytic activities

Abstract

Pt- and Pd-decorated carbon nanotubes (CNTs) have been prepared by diimide-activated amidation, an approach that avoids the harmful products of conventional SOCl2 treatment. In this study, N,N'-dicyclohexylcarbodiimide (DCC) was used as a coupling agent for the formation of an amide linkage. According to ICP measurements, the resulting materials consist of 7.1 wt.% loaded Pt and 8.6 wt.% loaded Pd. The TEM images show that size-similar and quasi-spherical nanoparticles are highly dispersed along the entire CNT walls. The prepared Pt-CNT exhibited an especially high oxidation current toward methanol, formic acid, and formaldehyde compared with that of the pristine CNT and a Pt/CNT mixture (10 wt.% Pt). Furthermore, the Pd-CNT displayed higher activity toward H2O2 reduction than that of the reference systems. The better catalytic activities can be explained by the high electrochemically active surface area that resulted from the smaller size and excellent dispersion of metal nanoparticles on CNT. These results demonstrate the DCC-activated amidation to be a very effective and useful way to tune size and disperse metal species in metal-decorated CNTs, markedly improving their catalytic activity. (C) 2011 Elsevier Ltd. All rights reserved.