In this thesis we explore proton transport through graphene membranes. We reveal that membranes with intrinsic defects in them show much larger proton conductivity than pristine-defect-free graphene along with lithium ion transport. We find that the energy barrier needed for protons and lithium ions to overcome and allow for penetration through graphene, reduces as the size of the defects in the graphene membranes increases. These graphene membranes show both good impermeability and ion transport properties and can be scaled up for industry. The ability for graphene to transport protons and block all other ions allows for the possibility of separating protons from other ions. By applying a potential to a graphene membrane we show that interfacial water can be dissociated into its constituent parts with the protons then transporting through graphene, physically separating the protons and hydroxide ions. Effectively we have used graphene as a proton permeable electrode. Moreover, water electrolysis was observed and occurred with perfect Faradaic efficiency, converting water into hydrogen and oxygen gas. Finally, we show that the proton conductivity through the suspended graphene devices is enhanced by shining white light onto the graphene membranes. The introduction will give the reader the background in order to understand the results presented here in published journal article format. The work shown here provides further insights into the proton and ion transport through graphene and describes a new way to look at interfacial reactions.
PROTON TRANSPORT THROUGH GRAPHENE: INTRINSIC DEFECTS AND ENHANCED WATER DISSOCIATION THROUGH 2D ELECTRODES
Griffin, E. (Author). 1 Aug 2023
Student thesis: Phd