Abstract:

Polyaniline was synthesized on the surface of flexible graphene paper by pulse voltage method. The composite material was used as free-standing and binder-free electrode and catalyst support in methanol fuel cells with deposited Pd nanoparticles via cyclic voltammetry. The surface morphology and chemical composition of the material were analyzed by scanning electron microscopy, X-ray photoelectron spectroscopy, and infrared spectroscopy, and the electrocatalytic performance of the electrode was investigated. The results show that graphene paper is flexible, that this fabrication procedure is efficient, and that polyaniline on the surface of the graphene paper is homogeneous. The existence of polyaniline can improve catalytic efficiency since the methanol oxidation peak current density increased from 3 mA·mg^-1 to 67 mA·mg^-1 with the addition of polyaniline. The lifespan of the catalyst is also prolonged according to I_f/I_b value (the oxidation peak current density ratio of forward scan and reverse scan) reaching 5.7.

Key words: Flexible graphene paper, Polyaniline, Pd nanoparticles, Catalytic anode, Direct methanol fuel cells