Electrodeposition of platinum-iridium nanoparticles on carbon nanotubes and their electrocatalytic oxidation of glucose

Abstract

Platinum-iridium (PtIr) nanoparticles (NPs) have been anchored on the surface of carbon nanotubes by potentiostatic electrodeposition in 0.5 M H₂SO₄+0.5 M glycerol aqueous solution. The surface and composition of the PtIr NPs/CNTs nanohybrids have been characterized by transmission electron microscopy and energy dispersive spectroscopy, respectively. The electrocatalytic properties of the PtIr NPs/CNTs catalysts for glucose oxidation have been investigated by cyclic voltammetry and chronoamperometry. The size of the PtIr NPs can be controlled from 3.0–7.0 nm by controlling the amount of Ir. In particular, the PtIr NPs has been optimized at 1:1 Pt/Ir atomic ratio. The as-prepared PtIr (1:1) NPs/CNTs catalysts possess unique properties including small size of PtIr NPs, excellent dispersion, high electrochemical active surface area and exhibit high activity towards glucose oxidation. For comparison, Pt NPs/CNTs catalysts have also been prepared under the same controlled procedure. In the absence of Ir, Pt NPs are also uniformly dispersed on the CNTs, and their average diameter is 4.0±0.5 nm, close to that of PtIr NPs. Further, addition of Ir makes PtIr (1:1) NPs/CNTs catalysts superior to
Pt NPs/CNTs catalysts in term of better long-term stability and higher catalytic efficiency of glucose oxidation. The
PtIr (1:1) NPs/CNTs catalysts are proved to be promising anode catalysts for direct glucose fuel cells.