Evaluating Electrospun Polyacrylic Acid-Nafion Composite As Stable Catalyst Support for PEM Fuel Cell Electrodes

Abstract

Production of energy through renewable and sustainable processes are important goals for the future in the context of depleting fossil fuels and environmental pollution. In this regard fuel cell technology offers an attractive combination of highly efficient fuel utilization and environmentally friendly operation. For successful commercialization of low temperature proton exchange membrane (PEM) fuel cells, they should have a long life and a high performance. Recently, high performance fuel cell electrodes were obtained by electrospinning a solution containing proton conducting Nafion and commercial platinum catalyst powder along with PAA as electrospinning polymer. Electrospinning of the catalyst together with Nafion ionomer resulted in enhanced triple phase boundaries which resulted in high fuel cell performance. Moreover, it was also found that the stability of the electrodes is significantly higher than the electrodes prepared from the same catalyst by conventional methods. However, carbon corrosion still ensued. In this work, we demonstrate the stability of polyacrylic acid (PAA) - Nafion composite as a stable support due to which the Pt after the carbon corrosion does not come out of the system. On the contrary, it stays entrapped in the membrane electrode assembly giving significance performance even after the corrosion protocols/measurements. Here, we first produce Pt nanoparticles that are produced by a photochemical reaction of the precursor induced by UV light. To this, PAA and Nafion (1:2 by weight) were added and stirred overnight. The resulting solution was electrospun. (Small amount of carbon was added in some cases to get the desired conductivity) to get a Pt/PAA-Nafion catalyst as shown in transmission electron micrograph. The electrodes are first tested for electrochemical stability by potential cycling and then in the fuel cell test bench using the FCCJ recommended cell evaluation protocol. Figure 1