Rational Electrode-Electrolyte Design for Efficient Ammonia Electrosynthesis under Ambient Conditions

Bryan H.R. Suryanto, Colin S.M. Kang, Dabin Wang, Changlong Xiao, Fengling Zhou, Luis Miguel Azofra, Luigi Cavallo, Xinyi Zhang, Douglas R. Macfarlane

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117 Citations (Scopus)

Abstract

Renewable energy-driven ammonia electrosynthesis by N2 reduction reaction (NRR) at ambient conditions is vital for sustainability of both the global population and energy demand. However, NRR under ambient conditions to date has been plagued with a low yield rate and selectivity (<10%) due to the more favorable hydrogen evolution reaction (HER) in aqueous media. Herein, surface area enhanced α-Fe nanorods grown on carbon fiber paper were used as NRR cathodes in an aprotic fluorinated solvent-ionic liquid mixture. Through this design, significantly enhanced NRR activity with an NH3 yield rate of ∼2.35 × 10-11 mol s-1 cmGSA-2, (3.71 × 10-13 mol s-1 cmECSA-2) and selectivity of ∼32% has been achieved under ambient conditions. This study reveals that the use of hydrophobic fluorinated aprotic electrolyte effectively limits the availability of protons and thus suppresses the competing HER. Therefore, electrode-electrolyte engineering is essential in advancing the NH3 electrosynthesis technology.

Original languageEnglish
Pages (from-to)1219-1224
Number of pages6
JournalACS Energy Letters
Volume3
Issue number6
DOIs
Publication statusPublished - 8 Jun 2018

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