Many industrial chemical processes involve a high-energy demand (often still derived from fossil fuels), toxic reactants, and the production of high amounts of waste. A good example is the production of ammonia and urea via the Haber-Bosh and Bosch-Meiser processes, respectively. These two nitrogen-containing compounds are mostly used in the fertilizer industry and with the increase in the world population, their production is expected to increase. Additionally, NH₃ itself is responsible for 2% of the annual world energy consumption and has a carbon footprint of 1.5 tons of CO₂ per ton of NH₃ [1]. Therefore, the development of more efficient, less hazardous technologies that are based on renewable energies to produce valuable N- containing compounds, has become one of the most challenging topics for chemical synthesis. By using electrochemical methods for the synthesis of ammonia and urea, toxic and dangerous chemicals can be replaced with clean electrons. Furthermore, the efficiency and selectivity of the reactions can be tuned by the applied potential, and more importantly, the energy used can come from renewable sources like wind or solar [2].

In this talk, I will show the recent advances from our group in the development of catalysts for the electrocatalytic synthesis of ammonia and urea (as for example Cu₂O and CuRh) and the reaction mechanism when using nitrate as a substrate [3].

References:

[1] S. Giddey, et al, Int. J. Hydrogen Energy, 38 (2013) 14576–14594

[2] Frontana-Uribe, B. A. et al; Green Chem. 2010, 12 (12) 2099– 2119

[3] D. Anastasiadou, Y. van Beek, M. C. Figueiredo, in preparation.

Figure 1: SEM images of two electrodeposited electrocatalysts used for ammonia and urea electrosynthesis from nitrates: a) CuRh and b) CuO.