Enhanced Catalytic Activity of Pt Nanostructured Electrodes Deposited by Spark Ablation for Proton Exchange Membrane...

Catalyst layers play a crucial role in determining the performance of proton exchange membrane fuel cells (PEMFCs). However, the deposition of catalyst layers poses challenges in PEMFC stack production due to the complexity of the fabrication steps. Herein, we present a simplified approach to synthesize Pt nanostructures via spark ablation and simultaneously deposit them onto gas diffusion layers (GDL). The in situ deposited catalyst layers on GDL serve as electrodes for membrane electrode assembly (MEA) fabrication. Moreover, the carrier gas in the spark ablation process significantly influences the nucleation and growth of the Pt nanostructures. Pt nanostructures produced in forming gas (Pt_FG, 95% nitrogen, and 5% hydrogen) exhibit dendritic morphology distinct from those obtained in pure N₂ (Pt_N₂). Investigating the catalytic activity of Pt synthesized in different carrier gases reveals that the Pt_FG catalyst demonstrates enhanced half-wave potential, mass activity, and durability compared to those of Pt_N₂ and commercial Pt-black catalysts. Single-cell measurements evaluate the electrocatalytic activity of the ionomer-free, in situ deposited catalyst layers. The Pt_FG MEA (0.2 mg_Pt cm^-2) achieves a power density of 1285 mW cm^-2 at 70 °C, 200 kPa, approximately 1.8 and 2 times higher than Pt_N₂ and Pt-black MEAs, respectively. Further reduction of the catalyst loading to 0.1 mg_Pt cm^-2 results in the Pt_FG MEA delivering 961 mW cm^-2, indicating enhanced catalytic activity and Pt utilization efficiency. This study provides insights into fabricating catalytic layers using a facile strategy, circumventing the need for catalyst synthesis, ink formation, and electrode coating techniques.