Graphene-Based Electrocatalysts for Oxygen Reduction Reaction in High Temperature Proton Exchange Membrane Fuel Cells

Abstract

Proton exchange membrane fuel cells play an essential role in a sustainable energy supply. However, a great challenge is the catalyst degradation regarding Pt instability and carbon corrosion. Nanocomposites combine the carbon support with corrosion-resistant metal oxides. In this study, tin-doped indium (III) oxide (ITO) and fluorine-doped tin (IV) oxide (FTO) are precipitated on reduced graphene oxide (rGO) and compared to multi-walled carbon nanotubes (MWCNTs), carbon black, carbon from hydrothermal carbonization (HTC-C) and rGO. Stress testing (0.05–1.47 VRHE) is used to assess their electrochemical durability. MWCNTs with the lowest specific surface area of 111 m2 g-1 and HTC-C with highest amorphousness and specific surface area of 546 m2 g-1 are most opposite, whereas HTC-C shows the strongest degradation. In case of the composites, degradation of FTO–rGO is insignificant, but ITO–rGO suffers from ITO degradation and carbon corrosion. In conclusion, FTO is not only more stable but persistently protects rGO from corrosion, so that the choice of metal oxide is crucial for catalyst’s durability.