Hybrid 1D titanium oxide nanowire – Reduced graphene oxide nanocomposites as efficient catalyst support for PEMFC

Abstract

With hydrogen being projected as the fuel of the future, proton exchange membrane fuel cells (PEMFC) have regained prominence as a zero-emission power source. Researchers are focusing on replacing the conventional carbon support used for the platinum catalysts with alternative materials to improve the durability of the electrocatalysts. Despite being a potential candidate, graphene-based materials have been limited by their lower limiting current density, possibly due to restacking of the graphene sheets. On this note, we introduced varying quantities of metal-oxide based 1D TiO2 nanowires to reduced graphene oxide (rGO) support and analysed their impact on the performance of the electrocatalyst. The optimized support with an initial content of 60 wt.% GO and 40 wt.% TiO2 exhibited higher mass transfer limiting current density, after Pt incorporation (Pt/TiO2-rGO), in comparison to the other composites. The catalyst showed higher retention in electrochemical surface area (1.42 times) and mass activity (1.48 times) compared to the commercial Pt/C after an accelerated durability test. Polarization studies carried out in a 25 cm2 fuel cell fixture exhibited a peak power density close to 720 mW cm−2 and almost two times higher current density (at 0.6 V) than the catalyst without TiO2. These results reaffirm the role of TiO2 in overcoming the limitations of graphene-based support.