Acetylene Contamination Mechanisms in the Cathode of Proton Exchange Membrane Fuel Cells

Abstract

The catalytic reactions of acetylene in contact with air, the electrochemical reactions of acetylene under different potentials, and the contamination reactions of acetylene in an operated proton exchange membrane fuel cell were investigated by using gas chromatography (GC), chronoamperometry, and cyclic voltammetry (CV) techniques. The GC results indicate that carbon dioxide is the catalytic reaction product of acetylene in the cathode and an electro‐oxidation product at high potentials, and it can desorb easily. Ethylene, ethane, and methane are the electrochemical reduction products of acetylene at low cathode potentials, and they can desorb easily. The CV analysis suggests the electroreduction intermediates are vinylidene and ethylidyne at low potentials and electro‐oxidation intermediates CO (or COH‐type species) at high potentials. In an operating fuel cell, acetylene reactions in the cathode include not only catalytic reactions, but also electrochemical redox reactions. According to these catalytic and electrochemical reactions, acetylene contamination mechanisms and possible effective contamination mitigation strategies are proposed.

Contamination Mechanisms of Proton Exchange Membrane Fuel Cells - Mass Transfer Overpotential Origin

“…5 The majority of the identified contaminants remain to be characterized preventing the development of contamination mechanisms that are important to devise effective mitigation strategies. Additionally, contamination mechanisms are generally species-specific due to, for example, the multitude of adsorbate configurations on the catalyst surface and chemical as well as electrochemical reactions 6 leaving many gaps in understanding including reactant mass transfer and water management.…”