Experimental study on PEMFC durability of cathode catalyst layers with different carbon supports under accelerated aging conditions

Catalyst-layer aging limits the durability of proton exchange membrane fuel cells, yet its dependence on carbon support and operating conditions during accelerated stress tests remains insufficiently understood. Here, a mesoporous-carbon-supported catalyst (Pt/MC) was compared with conventional Pt/C in square-wave voltage-cycling tests under different operating conditions. Polarization curves, cyclic voltammetry, electrochemical impedance spectroscopy and transmission electron microscopy were used to track performance decay and structural evolution. Although Pt/MC exhibited a greater loss of electrochemical surface area after aging, it showed a lower voltage decay at 3.0 A·cm −2 than Pt/C because of its slower increase in mass-transport resistance. Apart from the loss of active sites, the stability of the transport structure played a crucial role in the degradation of the catalyst layer. At 95 °C, Pt/MC retained relatively good durability. At 30 % RH, the mesoporous carbon support better preserved transport pathways and mitigated Pt agglomeration. In contrast, an upper potential limit of 1.0 V accelerated catalyst-layer degradation.