Hybrid Electrocatalysts Inspired by the Nitrogenase Enzyme

ended

Artificial nitrogen reduction to ammonia using the Haber-Bosch process directly supports half of the global food production and accounts for 2% of the global energy consumption. This large consumption of energy originates mostly from the use of H2 (derived from fossil fuels) as a reductant and from the high pressure and temperature required to undertake the Haber-Bosch process. Electrochemical synthesis of ammonia, using a proton and electron source combined with an electrocatalyst at room temperature to reduce N2, thus presents an appealing, energy-efficient alternative. However, despite years of research, the few currently available catalysts have very limited efficiency in N2 electroreduction. Drawing inspiration from biochemistry and using the tools of coordination chemistry, catalysis and surface chemistry, this project will explore an original strategy to develop catalysts for the reduction of N2 inspired by the nitrogenase enzyme. Motivated by the recent discovery of two unique moieties in the nitrogenase cofactor – the presence of a µ6-carbide moiety and a Mo(III) center – and of the increased understanding of substrate pathways in the nitrogenase protein structure, the goal of HEINE is to design new hybrid catalysts based on the immobilisation of accurate mimics of the nitrogenase active sites onto heterogeneous supports used to generate properties analogous of the protein scaffold (hydrophobicity, proton relays, etc.). This will provide us with novel ways to develop functional electrocatalysts for N2 reduction in ambient conditions, combining the activity of traditional solid-state systems, with the selectivity of molecular catalysts. By identifying and reproducing the parameters responsible for the unique activity of nitrogenase enzymes, HEINE will yield invaluable information on nature’s routes to N2 reduction and will pave the way towards a new generation of electrocatalysts able to promote this reaction.