Cathode durability enhancement under start-up/shut-down process using IrRuOx/C catalyst in polymer electrolyte membrane fuel cell

Abstract

The disruptive degradation of the electrode in the membrane electrode assembly (MEA) under the transient situation during the fuel cell electric vehicle operations such as fuel starvation, start-up and shut-down (SU/SD), etc. is to be addressed. To mitigate the carbon corrosion in the electrode, the catalyst for oxygen evolution reaction (OER) has been investigated recently. It evolves oxygen from water, thereby mitigating carbon corrosion at voltages over 1.5 V, which is typically induced during SU/SD cycles. In this study, carbon-supported IrRuOx catalysts towards OER are synthesized using a sub-substrate method, and their electrochemical and physicochemical properties are analyzed using several methods. Ir1Ru1Ox (Ir:Ru = 1:1 at. ratio in the oxide form) is observed to be the best catalyst in terms of activity and durability. The application of a 2.5 wt% OER catalyst to the cathode improves the carbon corrosion durability of the MEA by approximately 88 %. After 4000 SU/SD cycles, the electrochemical surface areas of the Pt in the OER-added MEA and reference MEA are reduced by 15 % and 57 %, respectively. When the OER catalyst is applied to the reference cathode electrode, it enhances the durability of the MEA without compromising the performance significantly.