Integrating polyoxometalate-single atom catalyst based (photo-) electrodes in flow reactors for reductive and oxidative nitrogen activation

• Applicants: Professor Dr. Carsten Streb; Professor Dr. Dirk Ziegenbalg
• Subject Area: Inorganic Molecular Chemistry - Synthesis and Characterisation
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 501934135

In this project, we propose the development of electrochemically driven reactors capable of coupling the nitrogen-to-ammonium reduction reaction (NRR) and the nitrogen-to nitrate oxidation reaction (NOR), leading to autonomous reactors for ammonium nitrate production from nitrogen, water and sustainable electricity. The project combines concepts from novel catalyst synthesis and stable electrode deposition to reactor design and materials-in-reactor integration. The project combines expertise in single-site catalyst development and electrode functionalization (PI Streb) with expertise in reaction engineering, mass transport optimization and reactor design (PI Ziegenbalg). In the second period, the project will develop noble-metal-free single site catalysts anchored on electrically conductive electrode supports. Variation of the SSC metal sites will allow control of NRR/NOR performance, while electrode anchoring will provide a stable, well-defined coordination environment. Electrode integration into continuous rotating electrode reactors will allow for an intensification of mass transport to increase NRR and NOR performance by matching of chemical and reaction-engineering requirements. The systems will be studied by in situ/operando electrochemical studies. This will provide insights from the atomic to the reactor-level on the catalytic performance, its limitations, and enable us to identify key optimization parameters. In sum, this project will develop flow reactors for decentralized ammonium nitrate production starting from molecular nitrogen, and uses modern materials design, advanced electrode fabrication, reaction engineering and process intensification to address challenges from the molecular to the reactor level.

• DFG Programme: Priority Programmes
• Subproject of: SPP 2370: Interlinking catalysts, mechanisms and reactor concepts for the conversion of dinitrogen by electrocatalytic, photocatalytic and photoelectrocatalytic methods (“Nitroconversion”)