Electrochemical synthesis of ammonia from nitric oxide in a membrane electrode assembly electrolyzer over a dual Fe-Ni single atom catalyst

Membrane electrode assembly (MEA) electrolyzers offer a means to scale up nitric oxide (NO)-to-ammonia (NH 3 ) electro-conversion assisted by renewable electricity and bring the anthropogenic nitrogen cycle back into balance. Herein, we show that atomically dispersed dual Fe, Ni atom embedded nitrogen-doped carbon nanotube (FeNi-NCNT) electrodes produce NH 3 readily with a low overpotential of 210 mV, among the lowest overpotentials reported for the electrosynthesis of NH 3 from NO. The FeNi-NCNT catalyst attains a high NH 3 faradaic efficiency (FE NH 3 ) of 92.6% at −0.5 V RHE . The high selectivity of FeNi-NCNT is believed to result from Ni sites lowering the activation energy and offering a stable intermediate during NH 3 formation. While integrating FeNi-NCNT in the MEA electrolyzer, high FE NH 3 of up to 83.6% was achieved at a current density of of about 71 mA cm −2 , presenting steady electrolysis over 50 h. This work guides employing dual-atom catalysts in MEA electrolyzer applications for efficient feedstock production. A dual-single atom catalyst, designed with Fe and Ni single atoms anchored on the carbon nanostructure, is employed on an MEA electrolyzer to demonstrate a high-rate NO electroreduction reaction to NH 3 at a very low over-potential.