Polypyrrole-modified hydrophobic carbon nanotubes as promising electrocatalyst supports in polymer electrolyte membrane fuel cells

As an alternative to oxidative acid treatment, a hydrophobic graphitized carbon nanotube (CNT) was functionalized with 1–4 nm thick polypyrrole (PPy) prior to application as catalyst supports in polymer electrolyte membrane (PEM) fuel cells. Unlike oxidative acid treatment, the PPy coating method converts the hydrophobic surface of a CNT to a hydrophilic one without creating defects on the surface of the CNT. As a result, Pt nanoparticles deposited on the PPy-coated CNTs showed an improved distribution, which significantly enhanced the fuel cell performance while preserving the intrinsic properties of the CNTs, i.e., resistance to electrochemical carbon corrosion. An additional advantage of PPy coating is that it prevents Pt nanoparticles from agglomerating on the CNT surface. These results indicated that PPy-coated CNTs are a promising catalyst support to improve both the performance and durability of PEM fuel cells.

► CNTs were functionalized with a thin layer of polypyrrole (PPy).
► It converts the hydrophobic surface of a CNT to a hydrophilic one without defects.
► The PPy coating improved distribution of catalysts and fuel cell performance.
► The PPy-coated CNTs preserved their resistance to electrochemical carbon corrosion.
► The PPy coating prevents agglomeration of Pt nanoparticles on the CNT surface.