Enhanced Triple-Phase Interface in PEMFC by Proton Conductor Absorption on the Pt Catalyst

Abstract

In a proton exchange membrane fuel cell (PEMFC), the membrane electrode assembly (MEA) is the core component and the region of the oxidation–reduction. In order to obtain a great performance, Pt with excellent catalyst efficiency is usually adopted in PEMFC as the catalyst. However, the high cost and poor durability remain the two major challenges in the application of PEMFC; thus, it is worth paying attention to enhance the utilization of the Pt catalyst and the stability of PEMFC. In this work, the Nafion array membrane with a larger specific surface and higher proton conductivity was applied to the cathode catalyst layer (CL) to prepare the ordered MEA. In order to improve the three-phase interface of the cathode CL, Nafion was adsorbed on the Pt particles as the proton conductor to expedite the proton transfer efficiency based on the principle that sulfonic acid is easily adsorbed on the Pt surface. In this case, the peak power density of PEMFC with Nafion absorption on the Pt surface is up to 843 mW cm–2 at the Pt loading of 61.4 μg cm–2, which is much higher than that of the fuel cell without a proton conductor on the Pt catalyst in the cathode CL (710 mW cm–2). Besides, the durability tests show that PEMFCs with Nafion absorption on the Pt catalyst surface can work continuously for 100 h without obvious voltage attenuation, which is more stable than that of the bare Pt for 70 h. In conclusion, Nafion as the proton conductor was adsorbed on the Pt catalyst surface of the cathode CL to enhance the triple-phase interface in PEMFC, which is expected to be a universal method to prepare PEMFCs with high stability and peak power density at a low preparation cost.