Novel catalysts and applications for polymer electrolyte membrane cells

Abstract

Polymer electrolyte membrane (PEM) water electrolysis represents a promising technology for the sustainable, emission-free hydrogen production from renewable energy, as it is able to quickly respond to fluctuations in the renewable energy supply. Nevertheless, natural scarcity of iridium, which is used as catalyst for the anodic water oxidation reaction, hinders wide-scale implementation of these cells. In this thesis we investigated how the performance of iridium catalysts can be improved by the addition of Sn and SnO2. Furthermore, despite their high efficiency, PEM cells are currently only employed for hydrogen production. We investigated whether it is possible to run other electrochemical transformations in PEM cells. Particularly, we focused on nitrate and nitric oxide reduction. These are pollutant molecules in ground water and in air, respectively. We investigated potential catalysts for the efficient transformation of these species to ammonia, which is a very important molecule for the fertilizer industry. Our approach can open new pathways for ammonia synthesis, replacing the energy-intensive, state-of-the-art Haber-Bosch process.ChemE/Catalysis Engineerin