Nanofibrous Electrodes with Tunable Electrodeposited Pt Morphologies with High ORR Activity and Durability

Abstract

A new approach for the preparation of PEMFC cathode electrocatalysts based on thin layers of platinum deposited on a support instead of conventional Pt nanoparticles supported on carbon black could be achieved adopting various Pt deposition techniques including atomic layer deposition, electrochemical atomic layer epitaxy, self-terminated Pt electrodeposition, thermal dealloying, and galvanostatic displacement of Ni and Cu ions with Pt1,2. This morphology allows for a more effective utilisation of the highly priced noble metal, while increases the durability of the electrodes over time. The morphology and nature of the support material also plays a crucial role. Nanostructured 1D materials have attracted significant research attention due to the influence of their nanostructure and porosity on performance and durability of the PEMFC3. In this regard, electrospinning is a reliable and scalable technique for the preparation of nanofibers with controlled and uniform diameters and structures. Its versatility allows the production of organic, hybrid and inorganic nanofibres, as well as the possibility of creating different geometries, assemblies and architectures4. We developed novel nanofibrous electrodes (NFE) based on 3D nanostructured networks of carbon nanofibers covered by Pt nanoislands, merging the advantage of Pt thin layers catalyst and a highly porous robust support. This was achieved by combining electrospinning and high overpotential pulsed Pt electrodeposition. These catalysts are based on self-standing electrospun carbon nanofibers covered by platinum thin platinum nanoislands. NFEs are highly durable when compared to commercial standards and have a higher degree of platinum exploitation. Electrochemical active specific surface areas as high as 140 m2g-1 Pt with retention in the order of 70 % after accelerated stress testing are measured, making them a suitable alternative to currently available commercial catalyst. 1. S. M. Alia, Y. Yan, and B. Pivovar, Catal. Sci. Technol., 4, 3589–3600 (2014) 2. G. Ercolano, S. Cavaliere, D. Jones, and J. Rozière, ECS Trans., 69, 1237–1242 (2015). 3. S. Cavaliere et al., ChemElectroChem, 2, 1966–1973 (2015). 4. S. Subianto et al., in Electrospinning for Advanced Energy and Environmental Applications, vol. 1, p. 29–60 (2015).