Electrocatalysis of oxygen reduction in alkaline media and a study of perfluorinated ionomer membrane degradation

Abstract

Oxygen Reduction Reaction (ORR) is an overarching technological and fundamental challenge in the context of electrochemical energy conversion. Recent developments in alkaline ionomer membranes that transport hydroxide anions have spurred research interests in the Alkaline Membrane Fuel Cell (AMFC) technology. Among several challenges such as improving hydroxide anion conductivity and anodic alcohol oxidation, a key source of overpotential loss is the cathodic ORR process. In this scenario, the fundamental understanding and design of novel electrocatalysts for ORR assume a crucial role. While Pt-based materials have been the mainstay in acidic medium, the dispensability of the so called "acid-stability" criterion permits the use of several non-noble metal based electrocatalysts for ORR in alkaline medium. In this dissertation a combination of catalyst synthesis, electrochemical studies and X-ray absorption spectroscopy (XAS) investigations have been carried to understand ORR in alkaline medium. Such a study is expected to provide a detailed understanding of the oxygen reduction mechanisms, pathways and ultimately methods to design novel electrocatalysts.