Ammonia Synthesis via Electrochemical Nitrogen Reduction Reaction on Iron Molybdate under Ambient Conditions

Abstract

The electrochemical nitrogen reduction reaction (NRR) is an environmentally friendly and sustainable strategy for ammonia synthesis under ambient conditions, in comparison with the traditional Haber‐Bosch process. However, the N≡N triple bond has a high bond energy, which causes the electrochemical NRR to suffer from sluggish kinetics. Inevitable ammonia contamination also disturbs the quantification of ammonia produced from the electrochemical NRR. To construct a bimetal‐atom active center to mimic nitrogenase in nature, we herein prepared iron molybdate, Fe2(MoO4)3, using it as catalyst for electrochemical NRR. It is active and stable with an NH3 yield rate of ca. 7.5 µg h–1 mgcat–1 and a Faradaic efficiency of ca. 1.0 % in 0.1 m Na2SO4 at –0.7 V for 2 h, due to synergistic effect of bimetal atoms. A series of comparative experiments were subsequently conducted to reveal the origin of the activity and estimate the deviation due to ammonia contamination from the environment. Our results hold great promise for both the design of catalysts and the accurate quantification of catalytic activity for electrochemical NRR.

Electrochemical Fixation of Nitrogen by Promoting N2 Adsorption and N–N Triple Bond Cleavage on the CoS2/MoS2 Nanocomposite

“…NH 3 has been widely used as the substance in industrial supplies and is vital to sustainable energy utilization in the future. − However, the current method for industrial NH 3 synthesis is mainly originated from the capital-intensive Haber-Bosch process, which not only requires relatively extreme conditions , but also leads to serious carbon dioxide emissions and environmental pollution. , Therefore, it is urgently required to explore a more green and efficient alternative for NH 3 production.…”

Recent Advances in MOF‐Based Materials for Photocatalytic Nitrogen Fixation

“…At present, commonly used methods for the detection of NH 4 + include spectrophotometry (such as Nessler's reagent method, indophenol blue method, salicylate method), ion chromatography, nuclear magnetic resonance (NMR) spectroscopy, and so on [83,84] . The detection methods of other products (such as NO 3 − and N 2 H 4 ) are usually ion chromatography or Watt and Chrisp method [85,86] . Herein, we will mainly focus on the detection method of NH 4 + .…”

Fe‐based catalysts for nitrogen reduction toward ammonia electrosynthesis under ambient conditions

“…The resulting FeMoO 4 nanorods retained their original morphology, crystal structure, chemical bonding state, and electrode transfer resistance, indicating that FeMoO 4 nanorods have NRR structural stability. Liu et al 72 . synthesized Fe 2 (MoO 4 ) 3 as an electrocatalytic NRR catalyst.…”

“…(G) Recycling tests at a potential of –0.7 V versus RHE of Fe 2 (MoO 4 ) 3 . Reproduced with permission 72 . Copyright 2020, Wiley.…”

“…The resulting FeMoO 4 nanorods retained their original morphology, crystal structure, chemical bonding state, and electrode transfer resistance, indicating that FeMoO 4 nanorods have NRR structural stability. Liu et al 72 synthesized Fe 2 (MoO 4 ) 3 as an electrocatalytic NRR catalyst. The Fe 2 (MoO 4 ) 3 catalyst exhibits an NH 3 yield of 7.5 μg h −1 mg cat −1 and FE of 1.0% in 0.1 M Na 2 SO 4 at −0.7 V versus RHE (Figure 8F).…”