Investigation of IrRu-based multi-functional Catalysts using sulfur doped-Ordered Mesoporous carbon Supports for Fuel Cell Reversal Tolerant Anode

Abstract

Fuel-Cell Electric Vehicles (FCEVs) have been considered as an attractive automobile due to high energy density, high-efficiency, and zero-emission features. Nevertheless, those have commercialization problems because of durability and cost issue. In particular, during FCEVs drive operation, the various transient condition cause H2 fuel starvation, leading to cell reversal voltage. This issue induces water electrolysis and carbon oxidation reaction at the fuel cell anode. As the Reversal Tolerant Anode (RTA) strategies, application of the Oxygen Evolution Reaction (OER) catalysts have been studied to promote the water oxidation rather than the carbon supports oxidation. Unfortunately, the addition of an OER catalyst into anode catalyst layer leads to degrading price competitiveness the of fuel cell. In previous study, IrRu-based alloy which has multi-functional catalytic activities for the hydrogen oxidation reaction (HOR) and OER was introduced. Herein, to maximize catalytic performance, sulfur doped order mesoporous carbons (S-OMC rod and platelet type) materials were used to as the OER catalyst supports with the purpose of increasing interaction between metal and supports. To validate sulfur doping effects, graphitized carbon and OMC were also used as the catalyst supports for the IrRu alloy. In the electrochemical measurement, IrRu4/S-OMC (platelet) was shown 6.51mA/cm2 of HOR kinetics current, which is higher than 4.54 mA/cm2 of the commercial Pt/C. In addition, OER activity at 10mA/cm2 showed at least an over-potential of 104 mV lower than the commercial IrO2. IrRu4/S-OMC was particularly observed the highest HOR-OER activity thanks to the strong interaction between Iridium and sulfur.