skip to main content

Title: Measuring the proton selectivity of graphene membranes

By systematically studying the proton selectivity of free-standing graphene membranes in aqueous solutions, we demonstrate that protons are transported by passing through defects. We study the current-voltage characteristics of single-layer graphene grown by chemical vapour deposition (CVD) when a concentration gradient of HCl exists across it. Our measurements can unambiguously determine that H{sup +} ions are responsible for the selective part of the ionic current. By comparing the observed reversal potentials with positive and negative controls, we demonstrate that the as-grown graphene is only weakly selective for protons. We use atomic layer deposition to block most of the defects in our CVD graphene. Our results show that a reduction in defect size decreases the ionic current but increases proton selectivity.
Authors:
;  [1] ; ; ;  [2]
  1. Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE (United Kingdom)
  2. Department of Engineering, University of Cambridge, Cambridge CB3 0FA (United Kingdom)
Publication Date:
OSTI Identifier:
22486132
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 107; Journal Issue: 21; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ABUNDANCE; AQUEOUS SOLUTIONS; CHEMICAL VAPOR DEPOSITION; COMPARATIVE EVALUATIONS; CURRENTS; ELECTRIC POTENTIAL; GRAPHENE; HYDROCHLORIC ACID; HYDROGEN IONS 1 PLUS; MEMBRANES; PROTONS