Electrodeposition of three-dimensional Pd nanoflowers on a PPy@MWCNTs with superior electrocatalytic activity for methanol electrooxidation

In this paper, polypyrrole@multi-walled carbon nanotubes (PPy@MWCNTs) nanocomposite as a catalyst support material is fabricated. Pd nanoflowers (NFs) were deposited on a PPy@MWCNTs modified glassy carbon electrode (GCE) by a facile electrochemical approach. The morphology and composition of the Pd NFs/PPy@MWCNTs are characterized by SEM (scanning electron microscopy) and EDS (energy dispersive spectroscopy), respectively. The catalytic performance of Pd NFs/PPY@MWCNTs catalyst is examined by cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy toward methanol oxidation reaction (MOR) in alkaline media. The mass activity of Pd NFs/PPY@MWCNTs (725 mA mg−1) is 8.09 times higher than that of the Pd NFs catalyst (89.6 mA mg−1). Meanwhile, the ratio of forward current (jf) to reverse current (jb) for the polymer supported catalyst is almost 2.6 times higher than that of the Pd NFs. Furthermore, PPY@MWCNTs produces a high activity to electrocatalyst, which might be due to higher electrochemically surface area and electronic conductivity. This strategy provides a promising platform for direct methanol fuel cells.