Platinum-nickel nanowires and nanotubes arrays as carbon-free cathodes for the PEM fuel cell

Othman Lagrichi (1, 2, 3) , Laure Guetaz (1) , Olivier Sicardy (1) , Denis Buttard (2, 3) , Arnaud Morin (1)

1 DEHT - Département de l'électricité et de l'hydrogène pour les transports
2 PHELIQS - PHotonique, ELectronique et Ingénierie QuantiqueS
3 SiNaps - Silicon Nanoelectronics Photonics and Structures

The cathode is the most crucial component of the PEMFC because the most limiting in terms of performance, durability and cost. Regarding the performance, the main losses are due to the cathode because of the negative coupling between a sluggish ORR and H+ and O2 transport losses issues. Therefore, a lot of efforts were conducted on the one hand to increase the kinetic of the ORR by developing catalyst with improved activity and stability. On the other hand, attempts have been conducted to reduce mass transport losses in the cathode by tuning its nanostructure. This paper describes a novel multi-step process to nano-structuring the electrocatalyst to simultaneously benefit from enhanced activity towards ORR and reduced O2 transport limitations. Thus, a new carbon-free architecture of electrodes made of organized and well-ordered and oriented PtNi nanowires and nanotubes directly embedded onto a Nafion® membrane was developed. Here, the nanotubes were templated from Ni nanowires grown on an anodic aluminium oxide (AAO) template. The fabrication process was optimized to improve the quality of the nanotubes and their integration into the membrane: the process includes a thermal treatment in H2/Ar environment and an acid leaching step as key steps to obtain the desired structure. After integrating the electrodes in a complete Membrane-Electrode Assembly (MEA), we tested the performance and durability of these nanostructures under real operating condition. We compared the results to a Pt/C conventional electrode at low Pt loading (~35µgPt/cm²) exhibiting an ECSA close to that of PtNiNWs and PtNiNTs electrodes. Results have shown a great improvement in mass activity and stability of PtNiNTs electrodes to AST. Also, they have shown a significant sensitivity towards RH variation.

Mots clés: Electrocatalyst; PEMFC; PtNi alloy; Oxygen Reduction Reaction (ORR); Electrode; Anodic Alumina Oxide; Ni Nanowires; Carbon-free electrode

Domaines: Chimie-Physique [physics.chem-ph]

Othman Lagrichi, Laure Guetaz, Olivier Sicardy, Denis Buttard, Arnaud Morin. Platinum-nickel nanowires and nanotubes arrays as carbon-free cathodes for the PEM fuel cell. ACS Applied Energy Materials, 2023, 2 (5), pp.11997-12012. ⟨10.1021/acsaem.2c01231⟩. ⟨cea-03813207⟩