Water splitting promoted by electronically conducting interlayer material in bipolar membranes
- 9 Downloads
Bipolar membranes are used in a variety of industrial applications to split water into hydronium and hydroxide ions. This research investigated the hypothesis that an electronically conducting material between the anion and cation exchange membranes can increase the rate of water splitting by increasing the electric field intensity in the mobile ion depleted region. Bipolar membranes were constructed with electronically conducting (graphene and carbon nanotubes) and electronically insulating (graphene oxide) interlayer materials of varying thickness. All three interlayer materials decreased the voltage required for water splitting compared to a bipolar membrane with no interlayer material. Quantum chemistry simulations were used to determine the catalytic effect of proton accepting and proton releasing sites on the three interlayer materials. Neither graphene nor carbon nanotubes had catalytic sites for water splitting. Thicker layers of graphene oxide resulted in decreased rates of water splitting at each applied potential. This effect can be attributed to a diminished electric field in the mobile ion depleted region with increasing catalyst layer thickness. In contrast, membrane performance with the electronically conducting graphene and carbon nanotube interlayers was independent of the interlayer thickness. An electrostatic model was used to show that interlayer electronic conductance can increase the electric field intensity in the mobile ion depleted region as compared to an electronically insulating material. Thus, including electronically conducting material in addition to a traditional catalyst may be a viable strategy for improving the performance of bipolar membranes.
KeywordsBipolar membrane Water splitting Electronically conducting interlayer Electric field Graphene Graphene oxide Carbon nanotubes
This research was supported by the National Science Foundation Chemical, Bioengineering, Environmental and Transport Systems (CBET) Division through Grant #1604857, and by a fellowship from Consejo Nacional de Ciencia y Tecnología (CONACYT), Mexico to Rodrigo J. Martínez through Grant #409178.
- 1.Kemperman AJ (2000) Handbook bipolar membrane technology. Twente University Press, EnschedeGoogle Scholar
- 8.Sheldeshov N, Zabolotskii V, Pis-menskaya N, Gnusin N (1986) Catalysis of water dissociation by the phosphoric-acid groups of an MB-3 bipolar membrane. Sov Electrochem (Engl Transl); (United States) 22:791Google Scholar
- 14.Fu R-Q, Xue Y-H, Xu T-W, Yang W-H (2005) Fundamental studies on the intermediate layer of a bipolar membrane. Part IV. Effect of polyvinyl alcohol (PVA) on water dissociation at the interface of a bipolar membrane. J Colloid Interface Sci 285:281–287. https://doi.org/10.1016/j.jcis.2004.11.050 CrossRefPubMedGoogle Scholar
- 21.Germandi A, Abdu S, Van de Ven E (2009) Critical review and assessment on the preparation of experimental as well as commercially available bipolar membranes. http://www.new-ed.eu/uploads/media/New_ED_Deliverable_D.1.1_01.pdf. Accessed 24 May 2019
- 22.Iravaninia M, Rowshanzamir S (2015) Polysulfone-based anion exchange membranes for potential application in solid alkaline fuel cells. J Renew Energy Environ 2:59Google Scholar