Preparation of high performance Pt/CNT catalysts stabilized by ethylenediaminetetraacetic acid disodium salt

A novel method with ethylenediaminetetraacetic acid disodium salt (EDTA-2Na) as a stabilizing agent was developed to prepare highly dispersed Pt nanoparticles on carbon nanotubes (CNTs) to use as proton exchange membrane (PEM) fuel cell catalysts. These nanocatalysts were obtained by altering the molar ratio of ethylenediaminetetraacetic acid disodium salt to chloroplatinic acid (EDTA-2Na/Pt) from 1:2, 1:1, 2:1 to 3:1. The well-dispersed Pt nanoparticles of around 1.5 nm in size on CNTs were obtained when the EDTA-2Na/Pt ratio was maintained at 1:1. And the Pt/CNT catalyst exhibited large electrochemical active surface areas, very high electrocatalytic activity and excellent stability in the oxidation of methanol at room temperature. The Pt/XC-72R catalyst with narrow size distribution was also prepared by this method for comparison purposes. Comparison of the catalytic properties of these catalysts revealed that the activity of the Pt/CNT catalyst was a factor of similar to 3 times higher than that of the Johnson Matthey catalyst and similar to 2 times higher than that of our Pt/XC-72R catalyst, which can be assigned to the high level of dispersion of Pt nanoparticles and the particular properties of the CNT supports.