Fabrication of membrane electrode assembly based on nafion/sulfonated graphene oxide nanocomposite by electroless deposition for proton exchange membrane fuel cells

Abstract

This report describes a fabrication route for membrane electrode assembly (MEA) with low Pt loading based on Nafion/sulfonated graphene oxide (SGO) nanocomposite membrane. The Pt catalyst was directly electroless deposited on both sides of Nafion/SGO membranes and electrochemical performance of the fabricated MEAs toward hydrogen adsorption/desorption reactions were studied. The effects of Nafion SGO content, Pt salt concentration, and SGO sulfonation level on the physicochemical and electrochemical characteristics of MEAs were investigated. The physicochemical properties of MEAs were studied by field emission scanning electron microscopy, water uptake (WU) measurements, and x-ray diffraction technique. Cyclic voltammetry, linear sweep voltammetry and electrochemical impedance spectroscopy techniques were applied to compare the electrochemical behavior of the prepared MEAs. WU of the best Nafion/SGO MEA appeared to be significantly higher than that of pure Nafion MEA (~ 2.5 times) and Nafion/GO MEA (~1.7 times). The electrochemical evaluation revealed the best Nafion/SGO MEA possessed a high electrochemical surface area of 67.4 m2 g−1, which was about 24 times and 50 % higher than those obtained for MEAs based on Nafion and Nafion/GO membranes. The best MEA showed high durability and retained about 93% of initial ECSA after 1000 cycles in an acidic solution. A high proton conductivity of 39.9 mS cm−1 was achieved for this MEA in which it was about 2.5 times and 1.9 times higher compared to those of MEAs prepared based on Nafion (15.9 mS cm−1) and Nafion/GO (20.7 mS cm−1).