Dynamic Simulation of Oxygen Transport Rates in Highly Ordered Electrodes for Proton Exchange Membrane Fuel Cells

Highly ordered Pt electrode has been recognized as an important technology for reducing Pt usage in fuel cells due to its improved oxygen transport capability. However, ordered Pt electrode can lead to the decrease in roughness of electrode, which in turn makes it unclear whether the improved oxygen transport can offset the decreased roughness of ordered electrode. Herein, we theoretically investigate the oxygen distribution, generated current, and minimum Pt loading of ordered Pt electrode based on kinetic model of oxygen transport. The results reveal that ordered Pt electrodes do not exhibit concentration polarization with the electrode thickness up to 100 μm. For ordered Pt electrode with diameter of nanorod of 60 nm, the limited current density reaches 110.2 A cm −2 that is much higher than that for conventional electrode without considering Ohmic loss and mass transport loss outside electrode. To generate a current of 1.5 A cm −2 at 0.67 V for fuel cell, the minimum Pt loading of cathode in PEMFC reaches 0.029 mg cm −2 assuming that the electrocatalyst nanorods contain 1 nm Pt layer at the outmost surface.