Abstract
Platinum is widely recognized for its high reactivity and is commonly used in the cathodes of polymer electrolyte fuel cells (PEFCs). However, due to its high cost and limited availability, there is a pressing need to reduce the amount of platinum used. Conventional low-platinum electrodes, comprised of Pt-supported carbon (Pt/C) and ionomer, face challenges such as catalyst dissolution and redeposition, carbon support corrosion, and platinum poisoning by the ionomer. This study focuses on Pt nanosheets (Pt(ns)) [1] as a novel catalyst with high activity and durability. These electrodes are considered to be a novel low-platinum electrode with high durability. In our previous research electrodes fabricated using Pt(ns) observed significant overvoltage in high-current density regions, attributed to hindered gas diffusion caused by catalyst stacking. Therefore, we aimed to reduce overvoltage by increasing the porosity of the electrode through the addition of a pore-forming agent. Inspired by reports on utilizing urea (Ur) to enhance electrode porosity [2], electrodes were prepared by incorporating Ur into the ink, followed by dissolution and removal to create voids. The resulting cathode catalyst layer was then hot-pressed to assemble the membrane-electrode assembly (MEA). I-V measurements demonstrated that the addition of Ur suppressed concentration overvoltage. Scanning electron microscopy (SEM) observations revealed increased electrode porosity compared to non-additive electrodes. Furthermore, despite a similar electrochemical surface area (ECSA) compared to non-additive electrodes, the mass activity (MA) in the low-current density region significantly improved.AcknowledgementPart of this paper is based on results obtained from a project, JPNP20003, subsidized by the New Energy and Industrial Technology Development Organization (NEDO).
Published Version
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