Bifunctional Electrocatalyst Materials for Improved Cell Reversal Tolerance in PEM Fuel Cell

Abstract

For several decades, proton exchange membrane fuel cells (PEMFCs) have been a topic of zero-emission energy conversion technology research, spanning from material development to system control. Most of the PEMFC research is focused on the cost reduction of catalyst and membrane as well as the improvement of the long-term durability. Harsh and dynamic operating conditions such as rapid load changes, cold start temperatures, insufficient gas supply or flooding of the anode with water lead to a fatal damage of the very thin anode catalyst layer. [1-2] During the hydrogen starvation, the carbon corrosion occurs to supply further protons and electrons to the cathode, resulting in an increase of the anode potential. This event is well-known as cell reserval and results in a decrease of the overall PEMFC performance.In this study, we evaluated a new catalyst concept by combining both functionalities (hydrogen oxidation reaction (HOR) and oxygen evolution reaction (OER)) in single nanoparticles. The potential of this bifunctional catalyst concept will be compared with the mostly used catalyst system prepared by a physical mixture of Pt/C and IrOx as co-catalyst. Controlling the chemical composition and structure of the bifunctional nanoparticle catalyst system allows to improve the cell reversal tolerance.