Electrochemical reduction of N 2 (NRR) is widely recognised as an alternative to the traditional Haber-Bosch production process for ammonia. The high-energy efficiency, low-cost variant of this process involves an aqueous electrolyte and there is now a substantial literature on this topic. However, though the challenges of NRR experiments have become better understood, the reported rates in these aqueous solution studies are often too low to be convincing that reduction of the highly unreactive N 2 molecule has actually been achieved. Unfortunately, there are many possible impurity sources that can interfere with robust measurements. In this presentation we will discuss the issues arising and critically reassess the status of this field of NRR reports, describing several experimental case studies of potential false-positives. It seems the Holy Grail of low cost production of ammonia in aqueous media remains elusive.
Choi, J., Suryanto, B.H.R., Wang, D. et al. Identification and elimination of false positives in electrochemical nitrogen reduction studies. Nat Commun 11, 5546 (2020)