Nanosheet arrays of iron oxide for enhanced ammonia synthesis via electrochemical nitrogen reduction for prospective algal membrane bioreactors

• Published in: Chemosphere (Oxford) 2023-10, Vol.338, p.139621-139621, Article 139621
• Main Authors: Younis, Muhammad Adnan, Manzoor, Saira, Ali, Amjad, Haq, Fazal, Aziz, Tariq, Kiran, Mehwish, Farid, Arshad, El Sayed, Mohamed E., Murshed, Mohammad N., El-Bahy, Zeinhom M., Akhtar, Muhammad Saeed
• Format: Article
• Language: English
• Subjects: Algal membrane bioreactors; Ambient condition; Ammonia synthesis; Electrocatalysis; Iron oxide nanosheets; Nitrogen reduction reaction
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2023.139621

The earth's nitrogen cycle relies on the effective conversion of nitrogen (N2) to ammonia (NH3). As a result, the research and development of catalysts that are earth-abundant, inexpensive, and highly efficient but do not need precious metals is of the utmost significance. In this investigation, we present a controlled synthesis technique to the fabrication of an iron oxide (Fe2O3) nanosheet array by annealing at temperatures ranging from 350 to 550 °C. This array will be used for the electrochemical reduction of atmospheric N2 to NH3 in electrolytes. The Fe2O3 nanosheet array that was produced as a result displays outstanding electrochemical performance as well as remarkable stability. When compared to a hydrogen electrode working under normal temperature and pressure conditions, the Fe2O3 nanosheet array produces an impressive NH3 production rate of 18.04 g per hour per mg of catalytically active material in 0.1 M KOH electrolyte, exhibiting an enhanced Faradaic efficiency (FE) of 13.5% at −0.35 V. This is accomplished by exhibiting an enhanced Faradaic efficiency (FE) of 0.1 M KOH electrolyte. The results of experiments and electrochemical studies reveal that the existence of cation defects in the Fe2O3 nanosheets plays an essential part in the enhancement of the electrocatalytic activity that takes place during nitrogen reduction reactions (NRR). This study not only contributes to the expanding family of transition-metal-based catalysts with increased electrocatalytic activity for NRR, but it also represents a substantial breakthrough in the design of catalysts that are based on transition metals, so it's a win-win. In addition, the use of Fe2O3 nanosheets as electrocatalysts has a lot of potential in algal membrane bioreactors because it makes nitrogen fixation easier, it encourages algae growth, and it makes nitrogen cycling more resource-efficient. [Display omitted] •The Fe2O3 nanosheets (Fe2O3-NS) were developed for NRR.•The electrocatalyst delivered excellent catalytic activity in 0.1 M KOH.•The highest FE of ∼13.5% and NH3 yield of ∼18.04 μg h−1 mg−1cat at −0.3 V was obtained.•The cation defects predominantly increase the active sites.•The potential of defect engineering on 2D materials for catalytic NRR was explored.