nz8b00487_si_001.pdf (1.89 MB)
Rational Electrode–Electrolyte Design for Efficient Ammonia Electrosynthesis under Ambient Conditions
journal contribution
posted on 2018-04-25, 00:00 authored by Bryan
H. R. Suryanto, Colin S. M. Kang, Dabin Wang, Changlong Xiao, Fengling Zhou, Luis Miguel Azofra, Luigi Cavallo, Xinyi Zhang, Douglas R. MacFarlaneRenewable
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.