Electro- and Photocatalytic N2 conversion with transition metal chalcogenides over 2D and 3D structured electrodes (NI-CONSTRUCT)
Ammonia is a versatile compound, which is present in the production chains of several products, including plastics and fertilizers. It is even seen as a viable liquid fuel replacement for many of the current uses of fossil fuels, from shipping to turbine fuels and - potentially - jet fuels. Recent progress in the capture and use of energy from renewable sources has opened possibilities in replacing the current industrial method for ammonia production, the Haber-Bosch process (an energy-intensive process that requires high temperature and pressure to operate), by an electrochemical process that can be done at room temperature and ambient pressure. This, however, is not an easy task, as demonstrated by the current state-of-the-art electrochemical ammonia production rates, which typically do not exceed a few micrograms of ammonia per hour in the laboratory scale.
The NI-CONSTRUCT project is carried out in the framework of the DFG’s priority programme “Nitroconversion” and aims to improve the currently achievable production rates of ammonia, by taking inspiration from nature. In particular, from nitrogenases, which are enzymes that are naturally present in nitrogen-fixing bacteria. Such enzymes make use of a molybdenum-, iron-, and sulphur-containing cofactor to convert the nitrogen into ammonia. Thus, MoFe oxides and sulphides (Fea-bMobOx-ySy) with varying metal ratios will be synthesized and tested for their photo- and electrochemical ability to catalyse the conversion of nitrogen to ammonia.
In addition to the development of promising new catalyst materials, the electrode of the electrochemical cell must be able to provide a large enough surface area for the reaction to occur, while simultaneously minimizing the diffusion paths of the gaseous N2 and liquid electrolyte. This will be done by using a gas diffusion electrode (GDE) fabricated using the Dynamic Hydrogen Bubble Templating method (DHBT), where the challenge lies in obtaining a pore structure that minimizes the diffusion paths of gases and liquids. Lastly, the solubility of N2 can also be increased in the electrolyte to facilitate its arrival on the catalytic centers. This can be done by using ionic liquids (ILs), which have been shown to effectively increase the solubility of N2. However, incorporating them into the nanostructure of GDEs (as opposed to the electrolyte itself), has not been demonstrated.
This project will be carried out in close collaboration between the Marschall Group (Universität Bayreuth), Roth Group (Universität Bayreuth), and Balducci Group (Friedrich-Schiller-Universität, Jena).
Duration: 09.2022 - 08.2025
Funding: Deutsche Forschungsgemeinschaft (DFG)
Contact: Dr.-Ing. Carlos Lobo, Prof. Dr.-Ing. Christina Roth
Priority programme: "Nitroconversion"