Fast growth of Au-Pt bimetallic nanoparticles on SWCNTs: Composition dependent electrocatalytic activity towards glucose and hydrogen peroxide

摘要

Growth of gold-platinum bimetallic nanoparticles (Au-PtNPs) on SWCNTs and their electrocatalytic activity towards the oxidation of glucose and the reduction of hydrogen peroxide (HP) were described. Initially, SWCNTs were synthesized on gold wire and characterized by field emission SEM (FE-SEM) and X-ray photoelectron spectroscopy (XPS). FE-SEM images showed that the SWCNTs have jungle-gym structure with 3 nm in diameter. Electroless deposition method was employed to grow Au-PtNPs on SWCNTs, in which Au/SWCNTs electrode was immersed in 0.3 mM HAuCl4 for 45 min followed by 0.3 mM H2PtCl6 for 15 min. Since SWCNTs are thermodynamically capable of reducing Au-3 (+) ions, they auto-catalyzed the reduction without the aid of any reducing agent and hence, the Au-PtNPs growth was achieved with in 15 min on SWCNTs. XPS confirmed the zero valent nature of Au and Pt deposited on SWCNTs. Further, the Au/SWCNTs/Au-PtNPs electrode exhibited composition dependent electrocatalytic activity towards glucose oxidation and HP reduction. A thin layer of Au-PtNPs (20:20 nm Au:Pt) on SWCNTs electrode effectively catalyzed glucose oxidation whereas thick layer (20:30 nm Au:Pt) catalyzed the HP reduction.