Fabrication and Performance of Membrane Electrode Assembly Using a Hydrophilic Pt/[TaOPO4/VC] Electrocatalyst

Abstract

Oxide- and phosphate-supported catalysts have been shown to promote the oxygen reduction reaction (ORR) in acid and alkaline electrolyte. We previously reported a high mass- and area-specific ORR activity for an electrocatalyst with 18 wt% loading of 2.4 nm Pt nanoparticles supported on a 3 wt% tantalum oxyphosphate-treated VC (Pt/[TaOPO4/VC]). The electrocatalyst was heat treated at 660°C in a reducing atmosphere and characterized using thin-film rotating disc electrode (RDE) in an acidic electrolyte and alkaline electrolyte. In this study, we focused on Proton exchange membrane fuel cell (PEMFC) catalyst layers (CLs) fabricated by by direct deposition of the Pt/[TaOPO4/VC] electrocatalyst as the active cathode material onto the HP Nafion® membranes using an in-house built ultrasonic spray system. We focused our attention on the addition of a surfactant (i.e. Triton X100) to the catalyst ink formulation, as it has been shown that a surfactant can improve the wetting characteristics of the ink. Performance evaluation and cross-sectional visualization of the CCMs were performed. The performance of the CCMs prepared using the Triton ink formulation is superior to the performance of the CCMs prepared using the Standard ink formulation for both for the Pt/[TaOPO4/VC] and the Pt/C electrocatalyst, especially in the high current density region.