Active and stable platinum-transition metal catalysts for oxygen reduction at high-temperature polymer electrolyte membrane fuel cells (PEMFCs)
Original Language Title: Stabilisierte aktive Platin-Übergangsmetallkatalysatoren für die Sauerstoffreduktion in Hochtemperatur-PEM-Brennstoffzellen
Fuel cell technology represents a clean and efficient energy conversion with high energy density and range. So far, however, this pioneering technology could not penetrate the market and compete with conventional internal combustion engines in the drive technology. The reasons are mainly found in the currently high costs of the systems.
The aim of the project DuraPEM was to integrate an economical synthesis of platinum-transition metal catalysts into production of high-temperature PEMFC membrane electrode assemblies (MEAs). The main objective of the work was the establishment of an active and stable catalyst system which could reduce the noble metal loading, thus the associated costs of a state-of-the-art membrane electrode assembly.
HT-PEM cathodes were prepared by impregnating gas diffusion electrodes with precursor solutions containing dissolved Pt and Co salts. The salts were reduced into the corresponding metallic nanoparticles by applying a heat treatment. In order to improve the catalytic properties of the Pt-Co/C catalysts post-preparation treatments, i.e. acid-leaching and annealing, were identified and introduced into the manufacturing process. This processes led to an increased electrochemical surface area, improved catalytic activity towards ORR and a higher stability against the corrosive environment of the HT-PEM fuel cell. The leached and heat-treated Pt-Co/C catalysts showed a very high stability in HT-PEM fuel cell operation under constant load and during start-stop cycling. In comparison to a commercial HT-PEM MEA the manufactured Pt-Co based HT-PEM MEA performed equally, even though having approx. 20% lower Pt-loading at the cathode.
Graz University of Technology - Institute of Chemical Engineering and Environmental Technology