Prussian Blue-Derived Fe@NC as an Efficient Electrocatalyst for Ammonia Synthesis under Ambient Conditions

Abstract

Presently, the Haber–Bosch process occupies predominance in ammonia (NH3) synthesis. However, it still suffers from serious drawbacks due to heavy CO2 emissions and large energy consumption. Ammonia synthesis via the electrocatalytic nitrogen reduction reaction (eNRR) under ambient conditions is deemed a promising alternative, but stable and efficient electrocatalysts are highly desired. Herein, Fe@NC was successfully synthesized via a facile annealing process using Prussian blue (PB) as a precursor. When used as catalysts for eNRR, Fe@NC exhibits good performances in a 0.1 M KOH + 0.1 M K2SO4 solution, with an average NH3 yield rate of 12.55 μg h–1 mgcat–1 and a corresponding faradic efficiency (FE) of 9.76% obtained at −0.2 V vs the reversible hydrogen electrode (RHE), which is comparable to and typically exceeds most reported values in this field. Furthermore, the Fe@NC catalyst presents high electrochemical stability along with excellent selectivity and durability.