Electrocatalysts based on graphene oxide and its buckypaper for enhanced Zn-air battery performance

Graphene oxide (GO) has been electrochemically synthesized by chronoamperometry and using a three-electrode system. Iron, manganese and cobalt phthalocyanines (FePc, MnPc and CoPc, respectively) have been incorporated to GO. These materials were characterized both physicochemically (X-ray Photoelectron Spectroscopy (XPS), UV–Vis, elemental analysis and Raman spectroscopy), morphologically (Transmission Electron Microscopy, TEM) and electrochemically (cyclic voltammetry). Electrochemical studies included the oxygen reduction reaction (ORR) and Zn-air battery performance using the synthesized electrocatalysts. In addition, graphene oxide buckypapers (GOBs) have been fabricated and evaluated as self-supporting electrodes for the Zn-air battery. Both GO/FePc and FePc supported on GOB (GOB/FePc), with a Fe content lower than 0.5 wt%, were subjected to Zn-air battery discharging tests. Both GO/FePc and GOB/FePc show comparable performance to the commercial Pt-based electrocatalyst using a much lower amount of metal.