Electrocatalysts for Acid Proton Exchange Membrane (PEM) Fuel Cells – an Overview

This chapter provides an overview about the acid PEM fuel cell, its design and operation, and the underlying thermodynamic principles. The cathode reaction, namely, electrocatalytic oxygen reduction (ORR, oxygen reduction reaction) is discussed in some detail with respect to electrode kinetics and catalysis. As will become clear, the ORR is a major challenge in current fuel cell research both from the fundamental as well as from the applications point of view. The state of the art in Pt-based acid PEM fuel cell catalysts is presented and the future potential of these catalysts is critically discussed. An overview about alternative catalyst systems, which in the future might replace Pt-based materials, is given. This chapter is intended to provide the background for more specialized chapters that follow.