Metallocorroles: Molecular Electrocatalysts for Oxygen Reduction Reaction for Fuel Cells

Lior Elbaz, Chemistry Department, Bar-Ilan University, Ramat-Gan, Israel

The increasing need to reduce our ecological footprint and our dependence on fossil fuels has given rise to the search for cleaner, cheaper and more efficient technology to power our houses, plants, cars and electronic devices. The most promising alternative energy technology today for automotive, main- and backup-power is polymer electrolyte fuel cells (PEMFCs).

The greatest challenges for this technology has been the reduction of its cost and its durability. Recent cost analysis has shown that most of the fuel cell cost is spent on the fuel cell stack¹ where the catalyst, in most cases - platinum, is the most expensive constituent (more than 49% of the total cost) and thus serves the biggest impediment to the introduction of this technology to the market. Hence non-precious metal catalysts (NPMC) need to be developed in order to replace the current Pt-based catalysts, mainly at the fuel cell cathode, where oxygen reduction reaction (ORR) takes place.

Recently, Metallocorroles, a relatively new family of NPMC was reported by us to have very good potential as non-precious metal catalysts for ORR. The effect of the different metal centers, the substituents on the meso- and beta-positions, interactions with the support and with neighboring catalytic centers may have a significant impact on the way we design and utilize non-precious metal catalysts as a whole, and metallocorroles in particular. In this talk, all of the above parameters will be discussed. In particular, we will show how different substituents on the meso-positions affect the ORR activity and mechanism, and answer the question: Is it important to have electron-withdrawing functionalities near the catalytic center? and if so, what is their effect? We will show how covalently attached centers work synergistically towards ORR electrocatalysis, and try to shed some light on the importance of the surface functionalities in carbonaceous supports.