Suppressing methanol crossover with a deposited quaternary Pt-based catalyst on the Nafion surface

A Pt49-Ru35-Ir6-Os10 alloy layer is deposited on the Nafion membrane surface using the impregnation-reduction (IR) method to mitigate methanol crossover. The methanol crossover in a membrane electrode assembly (MEA) with a deposited Pt-Ru-Ir-Os layer is compared with a MEA without any layer on the proton exchange membrane (PEM). The deposited Pt49-Ru35-Ir6-Os10 layer functions like a catalytically active layer, a methanol barrier, and an electrode all at the same time. This layer yields up to a 30% suppression of methanol crossover and a 15% improvement in fuel cell voltage performance (@170 mA cm−2) at 80 °C. The porous metal alloy layer with a high surface area of the Pt-Ru layer suppresses methanol crossover by the catalytic activity of the deposited layer. The presence of the solid Pt49-Ru35-Ir6-Os10 layer on the Nafion membrane surface reduces the proton conductivity of the PEM (from 10.75 to 4.22 mS cm−1), and degrades the output of the cell voltage performance (from 0.350 to 0.335 V at 90 mA cm−2 of current density) at 60 °C, even though methanol crossover is reduced (from 6928 ppm to 4415 ppm (CO2 concentration at cathode exhaust is proportional to methanol crossover)).