Here we present a novel approach to electrocatalysts layer design for PEMFC. Pt conformally electrodeposited around surface of carbon nanotubes growth on a self-standing nanofibrous electrode (NFE). We found that by combining two cost-effective and up-scalable techniques, electrospinning and electrodeposition it is possible to produce a layered electrode with tuneable lacunarity and engineer the surface area distribution along the electrode thickness and in turn the Pt content distribution.

It is possible to obtain an electrocatalyst with outstanding Pt exploitation and high durability while minimizing fabrication complexity^[1]. We produced hierarchical 3D electrocatalyst layers with tuneable morphology that can be used directly in a membrane electrode assembly, allowing the complete exploitation of their highly porous structure, in a similar fashion to NSTF^[2] or other 3D macroscopic assembly techniques. These structured electrocatalyst layers have high electrical conductivity for fast charge transport, and engineered density for efficient reactant mass transportation. This method allowed us to obtain self-standing nanofibrous electrodes with ultra-low Pt loading (0.05 mg/cm 2), that show very high activity towards the oxygen reduction reaction and electrochemical surface areas as high as 150 m²/g. A detailed microscopic, structural and electrochemical characterisation of the complete electrodes, including their application as the cathode in a proton exchange membrane fuel cell is presented.

[1] G. Ercolano, F. Farina, S. Cavaliere, D.J. Jones, J. Rozière, J. Mater. Chem. A 5 (2017) 3974-3980.

[2] M.K. Debe, A.K. Schmoeckel, G.D. Vernstrom, R. Atanasoski, J. Power Sources 161 (2006) 1002–1011.

Acknowledgement: This project has received funding from the Fuel Cells and Hydrogen 2 Joint Undertaking under grant agreement No 700127 INSPIRE. This Joint Undertaking receives support from the European Union’s Horizon 2020 research and innovation programme.