Effects of the Chemical Treatment on the Physical-Chemical and Electrochemical Properties of the Commercial Nafion™ NR212 Membrane

Abstract

Polymer Electrolyte Fuel Cells (PEFCs) are one of the most promising power generation systems. The main component of a PEFC is the proton exchange membrane (PEM), object of intense research to improve the efficiency of the cell. The most commonly and commercially successful used PEMs are Nafion™ perfluorosulfonic acid (PFSA) membranes, taken as a reference for the development of innovative and alternative membranes. Usually, these membranes undergo different pre-treatments to enhance their characteristics. With the aim of understanding the utility and the effects of such pre-treatments, in this study, a commercial Nafion™ NR212 membrane was subjected to two different chemical pre-treatments, before usage. HNO3 or H2O2 were selected as chemical agents because the most widely used ones in the procedure protocols in order to prepare the membrane in a well-defined reference state. The pre-treated membranes properties were compared to an untreated membrane, used as-received. The investigation has showed that the pre-treatments enhance the hydrophilicity and increase the water molecules coordinated to the sulphonic groups in the membrane structure, on the other hand the swelling of the membranes also increases. As a consequence, the untreated membrane shows a better mechanical resistance, a good electrochemical performance and durability in fuel cell operations, orienting toward the use of the NR212 membrane without any chemical pre-treatment.

Quantification of Organic Solvent Concentration Profiles in Ion Exchange Membranes Via Confocal Raman Microscopy

“…[62] Aboki et al, Bayer et al, and Hink et al recorded higher swellings in water of approximately 28%, 16%, and 17%. On the other hand, Passalacqua et al [63][64][65][66] recorded a low swelling of approximately 4% for water-saturated Nafion 212 membranes. The inconsistency in literature might result from different membrane pretreatments, measurement methods, and experimental conditions.…”

The Effect of Salty Environments on the Degradation Behavior and Mechanical Properties of Nafion Membranes

“…Then, the membranes were boiled successively in 3% hydrogen peroxide solution, distilled water, 1.0 M sulfuric acid solution, and distilled water for 1 h each as a swelling pretreatment. The purpose of the pretreatment is to enhance the connection between the hydrophilic channels and to provide protons as counterions to the sulfonate groups [15,16].…”

Anode Reaction Control for a Single‐Compartment Electrochemical CO2 Reduction Reactor with a Surface‐Activated Diamond Cathode

“…A modification of hot press conditions and a decrease in the thickness of Nafion® membrane (NR-211, 25 μm) did not improve the peeling-off of Nafion® membrane from IrO 2 electrode. Whereas numbers of Nafion® membranes coated electrodes have been reported, [52][53][54][55][56][57][58][59][60][61][62][63] the reports of OER at the Nafion® membrane coated electrode are limited. [44,63] These references did not discuss the durability of the hot pressed Nafion® film on the electrodes.…”