Effect of graphene aerogel as a catalyst layer additive on performance of direct methanol fuel cell

Abstract

Efficient methanol oxidation reaction is the first requirement of the electrocatalyst of a Direct methanol fuel cell (DMFC), which is determined by its catalyst material and preparation method. In this work, a novel electrocatalyst used in anode is prepared by using graphene aerogel (GA) as a supporting material with platinum and Nafion binder by spray coating. The physical and chemical properties of the electrocatalyst are examined with scanning electron microscope (SEM), Electrochemical impedance spectroscopy (EIS), and polarization curves. The SEM results show that graphene aerogel based electrocatalysts possess a three-dimensional structure with uniform dispersion of nanostructure, which enlarges the activation area of the electrocatalyst and produces more protons and electrons. Moreover, the well-developed porous structure provides a less resistance and smooth pathway for protons to reach the cathode. The results show that with 10 % GA and 50 % Nafion as binder, the current density reaches at the value of 42.62 mW·cm−2 respectively, which is 13.5 % higher than the maximum power density of 37.56 mW·cm−2 of traditional carbon-catalyst layer (C-CL) electrode. Moreover, when temperature increases from 50 to 70 ℃, the novel catalytic layer electrode (GA-CL) doped with GA as an additive delivers 95.8 % increment in power density.