Applicability of Graphene Oxide Interlayers in PEMs for Reducing Crossover in Electrochemical Acetone Hydrogenation Reactors

Reactant and product crossover is challenging for proton exchange membrane (PEM)-based electrochemical systems, as it leads to efficiency losses and safety issues. Blocking interlayers can reduce the permeability of PEMs. In this work, a reduction in organic crossover by up to 55% is reached by implementing graphene oxide (GO) flakes in a Nafion membrane for application in an acetone hydrogenation reactor. Additionally, the GO-membrane’s hydrogen crossover is reduced significantly. Those effects are accompanied by an up to 12% increased OCV and scale with the GO interlayer loading. The performance of the MEAs containing GO composite membranes is slightly reduced. This performance loss is traced back to an increased high-frequency resistance (HFR) of the GO composite membranes, the effect of an additional interface resistance resulting from the GO interlayer, and manufacturing-dependent variations in the electrochemically active surface area. Impedance analysis suggests a rearrangement of the GO flakes during operation, reflected by a decreasing HFR and interfacial resistance of the blocking interlayer after the net 15 h lasting electrochemical test protocol. This observation is supported by transmission electron microscopy, which shows structural variations in the GO interlayer at EoT. Nonetheless, the reduction in organic and hydrogen crossover is maintained at EoT.