Book/Dissertation / PhD Thesis

FZJ-2026-02328

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Characterization of Nitrogen Reduction Reaction Catalysts for the electrochemical Ammonia Synthesis

Sachse, D. (Corresponding author)FZJ*

2026
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag Jülich
ISBN: 978-3-95806-907-7

This record in other databases:  

Please use a persistent id in citations: urn:nbn:de:0001-2607011403402.303482556443  doi:10.34734/FZJ-2026-02328

Abstract: "Bread from Air". Was the guiding principle behind intensive research into the industrial production of ammonia (NH3) at the beginning of the 20th century. The development of the Haber-Bosch process finally enabled the industrial production of NH3. NH3 with an annual production of 170 millions tons, is one of the most produced chemicals worldwide. Around80 % of the produced NH3 quantity is utilized as fertilizer to sustain the world population with food. According to estimates, only two to three billion people could be fed if there were no artificial fertilizers. However, the Haber-Bosch process is highly energy-intensive. Approximately1 % of the globally generated energy is consumed for ammonia production, contributing to 1- 2 % of annual CO 2 emissions. Due to the ecological and climatic significance, it is imperative to gain NH3 and its components, hydrogen (H2) and nitrogen (N2), efficiently from renewable energy sources. The objective of the present thesis is the continuous electrochemical synthesis of ammonia in an electrochemical membrane electrode assembly (MEA) cell and its in-depth analysis. A test-rig was developed and constructed for the experiments. The process of electrochemical oxygen (O2) depletion and N2 enrichment by an oxygen-depolarized cathode was analyzed and optimized with regard to the cell and process parameters. The residual oxygen content could be reduced to less than1 % . The electrochemical nitrogen reduction reaction (eNRR) was explored and characterized using a variety of promising catalysts under different cell configurations and process conditions. Nevertheless, the measured production rates were within the error range of the spectroscopic detection method. Therefore, it is not possible to synthesize NH3 under the tested conditions. NH3 was detected under process conditions that, based on theoretical calculations, do not allow NH3 synthesis from N2. Subsequently, a comprehensive examination of the adsorption and desorption behavior NH3 in the electrochemical cell was conducted. Especially the membrane was examined in detail. It was found that small amounts of NH3 do not affect the properties of the membrane. As a result, the synthesis and its process conditions remain unknown. The desorption of NH3 from the cell occurred under conditions where synthesis is not possible. Finally an novel electrochemical NH3 recycling process was developed and analyzed. This process utilizes the adsorption and desorption properties of the membrane in order to recycle NH3 from aqueous solutions. This process demonstrates a method for recycling and reusing NH3 from wastewater, while producing H2 as a by-product.

Note: Dissertation, RWTH Aachen University, 2026

---

Contributing Institute(s):

1. Elektrochemische Verfahrenstechnik (IET-4)

Research Program(s):

1. 1231 - Electrochemistry for Hydrogen (POF4-123) (POF4-123)

Appears in the scientific report 2026

---

Database coverage:
;

---