Preparation and characterization of graphene oxide based membranes as possible Gas Diffusion Layers for PEM fuel cells with enhanced surface homogeneity

Abstract

The aim of this work is to define and optimize a process to produce a membrane made of reduced graphene oxide, r-GO, aiming to use it as Gas Diffusion Layer, GDL, in a Polymer Electrolyte Membrane Fuel Cell, PEMFC. Some works have reported that r-GO could reach conductivity values of about 10 4 S/m; by using the "self-assembling" properties of GO, it would be possible to obtain a GDL with enhanced homogeneity, which maintains a good electronic conductivity. A reduction process of GO in aqueous solution was developed in order to get the desired conductivity value of the final product. The membrane was characterized through several techniques to assess key parameters and to understand its properties. In this work it was possible to obtain a membrane which has a maximum contact angle of 86° and a conductivity of about 421 S/m.

Reduced Graphene Oxide Membranes as Potential Self-Assembling Filter for Wastewater Treatment

“…[23]. The mixture was stirred at room temperature for 24, 48, or 72 h; these reduction times have already proved, in a previous work, to preserve both self-assembling properties and integrity of the membrane surface [23].…”

“…Upo increasing the reduction time, one can observe a clear and progressive decrease of th intensity of the characteristic GO reflection around 11° 2θ [28,29]. A corresponding inte layer distance of 7.98 Å was calculated, more than two-fold that of graphite (d = 3.4 Å The larger interlayer distance of GO has been reported to be due to the oxygen-containin functional groups of the basal plane and to water molecules intercalated between laye [23,28]. All rGO membranes exhibit an appreciable macroscopic roughness which increases with the reduction time.…”

“…A 4 mg/mL commercial GO dispersion (Graphenea, San Sebastian, Spain) was used, consisting of monolayer GO flakes (<10 µm) dispersed in water at pH 2.2-2.5. The rGO solution was prepared according to [23] by diluting the commercial aqueous dispersion at a final GO concentration of 0.4 wt.%, after dehydrated L-AA was added in the ratio GO/L-AA = 1/10 (wt./wt.) [23].…”

“…The rGO solution was prepared according to [23] by diluting the commercial aqueous dispersion at a final GO concentration of 0.4 wt.%, after dehydrated L-AA was added in the ratio GO/L-AA = 1/10 (wt./wt.) [23]. The mixture was stirred at room temperature for 24, 48, or 72 h; these reduction times have already proved, in a previous work, to preserve both self-assembling properties and integrity of the membrane surface [23].…”

“…In the literature it has been proposed that reduced graphene oxide (rGO) can show improved filtration properties [19]. rGO can be easily obtained by reducing GO; the reduction may partially affect the ability of forming stable filter membranes, which is considered to rely on a macroscopic mechanical behavior [19,23]. Membrane formation derives from the abovementioned self-assembling capability of GO, which may be kept if a moderate and controlled reduction of its oxygen functional groups is carried out.…”