Balancing Water Dissociation and Current Densities to Enable Sustainable Hydrogen Production with Bipolar Membranes in Microbial Electrolysis Cells

Xu Wang, Ruggero Rossi, Zhifei Yan, Wulin Yang, Michael A. Hickner, Thomas E. Mallouk, Bruce E. Logan

Research output: Contribution to journalArticle

2 Scopus citations

Abstract

Hydrogen production using two-chamber microbial electrolysis cells (MECs) is usually adversely impacted by a rapid rise in catholyte pH because of proton consumption for the hydrogen evolution reaction. While using a bipolar membrane (BPM) will maintain a more constant electrolyte pH, the large voltage loss across this membrane reduces performance. To overcome these limitations, we used an acidic catholyte to compensate for the potential loss incurred by using a BPM. A hydrogen production rate of 1.2 ± 0.7 L-H2/L/d (jmax = 10 ± 0.4 A/m2) was obtained using a Pt cathode and BPM with a pH difference (ΔpH = 6.1) between the two chambers. This production rate was 2.8 times greater than that of a conventional MEC with an anion exchange membrane (AEM, 0.43 ± 0.1 L-H2/L/d, jmax = 6.5 ± 0.3 A/m2). The catholyte pH gradually increased to 11 ± 0.3 over 9 days using the BPM and Pt/C, which decreased current production (jmax = 2.5 ± 0.3 A/m2). However, this performance was much better than that obtained using an AEM as the catholyte pH increased to 10 ± 0.4 after just one day. The use of an activated carbon cathode with the BPM enabled stable performance over a longer period of 12 days, although it reduced the hydrogen production rate (0.45 ± 0.1 L-H2/L/d).

Original languageEnglish (US)
Pages (from-to)14761-14768
Number of pages8
JournalEnvironmental Science and Technology
Volume53
Issue number24
DOIs
StatePublished - Dec 17 2019

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Environmental Chemistry

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