Design Strategies for Support and Electrocatalyst Materials in Polymer Electrolyte Fuel Cells

Abstract

The primary goals in catalysis are high activity, selectivity and stability in the target reaction while keeping the material and production costs low. In the last decades, the understanding of fundamental catalytic processes on an atomic level has led to substantial improvement in catalyst design. Among other factors, control of shape and surface composition of catalyst nanoparticles has demonstrated its importance for various industrially relevant reactions. In this conference contribution, we will elaborate on selected prerequisites for active and stable electrocatalysts for the oxygen reduction reaction and the important role of the carbon support. Specifically, we will focus on shape-controlled [1] and core-shell structures and the implication of core design and shell engineering for the overall performance.[2] We will demonstrate how to reduce the noble metal loading while maintaining a high stability through support passivation. This will be exemplarily demonstrated on a Titanium carbide / Platinum system.[3] By using potential-triggered passivation of titanium carbide, irregularities in the Pt film heal out via the formation of insoluble oxide species at the solid/liquid interface. The adaptation of the described catalyst design to the nanoscale and to high-surface area structures highlight the potential for stable, passivating catalyst systems for various electrocatalytic reactions.