Aniline as a dispersant and stabilizer for the preparation of Pt nanoparticles deposited on carbon nanotubes

A novel method has been developed to debundle carbon nanotubes (CNTs) and load Pt nanoparticles on them without damaging their graphene structures. In this article, the aniline acts as a very efficient dispersing agent to debundle CNTs from 200 to 50 nm at a very low concentration of 0.5% in an IPA/water solution. The aniline-stabilized CNTs have a larger pore volume and larger amount of mesopores than pristine CNTs, and the debundling of CNTs by aniline appears to be a physical rather than a chemical process. Meanwhile, under the presence of aniline, the Pt nanoparticles are anchored on CNTs with a uniform dispersion and small particle size distribution (1.9 ± 0.4, 2.1 ± 0.3, and 2.4 ± 0.4 nm for 14.9%, 29.1%, and 49.0% Pt/CNT, respectively). It is clear that aniline functions as a dispersant and a stabilizer in this paper. These nanocomposites are applied as electrocatalysts for the cathode of a direct methanol fuel cell. The electrochemical active surface areas of Pt/CNT catalysts are higher than that of E-TEK. Compared to the E-TEK cathode catalyst, the mass activity of Pt in 14.9% Pt/CNT is 45.9 W g^-1 Pt, which is about 50% higher than that of E-TEK (31.4 W g^-1 Pt). The result indicates that aniline is an efficient dispersant and stabilizer for the preparation of Pt nanoparticles deposited on CNTs. Additionally, the whole process, which could be easily scaled up for industrial production, is simple, efficient, and inexpensive.