Comparison of cathode catalyst binders for the hydrogen evolution reaction in microbial electrolysis cells

Type
Article

Authors
Ivanov, Ivan
Ahn, YongTae
Poirson, Thibault
Hickner, Michael A.
Logan, Bruce

KAUST Grant Number
KUS-I1-003-13

Online Publication Date
2017-06-02

Print Publication Date
2017-06

Date
2017-06-02

Abstract
Nafion is commonly used as a catalyst binder in many types of electrochemical cells, but less expensive binders are needed for the cathodes in microbial electrolysis cells (MECs) which are operated in neutral pH buffers, and reverse electrodialysis stacks (RED),which use thermolytic solutions such as ammonium bicarbonate. Six different binders were examined based on differences in ion exchange properties (anionic: Nafion, BPSH20, BPSH40, S-Radel; cationic: Q-Radel; and neutral: Radel, BAEH) and hydrophobicity based on water uptake (0%, Radel; 17–56% for the other binders). BPSH40 had similar performance to Nafion based on steady-state polarization single electrode experiments in a neutral pH phosphate buffer, and slightly better performance in ammonium bicarbonate. Three different Mo-based catalysts were examined as alternatives to Pt, with MoB showing the best performance under steady-state polarization. In MECs, MoB/BPSH40 performed similarly to Pt with Nafion or Radel binders. The main distinguishing feature of the BPSH40 was that it is very hydrophilic, and thus it had a greater water content (56%) than the other binders (0–44%). These results suggest the binders for hydrogen evolution in MECs should be designed to have a high water content without sacrificing ionic or electronic conductivity in the electrode.

Citation
Ivanov I, Ahn Y, Poirson T, Hickner MA, Logan BE (2017) Comparison of cathode catalyst binders for the hydrogen evolution reaction in microbial electrolysis cells. International Journal of Hydrogen Energy 42: 15739–15744. Available: http://dx.doi.org/10.1016/j.ijhydene.2017.05.089.

Acknowledgements
This research was supported by National Renewable Energy Laboratory (NREL), project no. ZFA-5-52002-01, and Award KUS-I1-003-13 from the King Abdullah University of Science and Technology (KAUST).

Publisher
Elsevier BV

Journal
International Journal of Hydrogen Energy

DOI
10.1016/j.ijhydene.2017.05.089

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