Activation of Dinitrogen Molecule (N2) in Unconventional Electrochemical Reactors for Ammonia Production

In this study, we present the development of a novel electrochemical device designed for the nitrogen reduction reaction (NRR) process, which operates under unconventional conditions. This zero-gap flow cell works without a liquid electrolyte in the cathodic section and incorporates novel electrocatalysts integrated into gas diffusion electrodes (GDEs). Specifically, the electrocatalysts are based on ruthenium (Ru), deposited on alumina (Al2O3) or carbon nanotubes (CNTs). A key objective of this study is to evaluate the partial or total replacement of Ru with a more abundant and cost-effective material, such as iron (Fe). The productivity of the produced NH3 (in ?g mgcat-1 h-1) and the Faradaic Efficiency (FE) are provided and discussed. Another important aspect of this work is how ammonia contamination is addressed, using a cheaper but still rigorous protocol than the one reported in the literature using expensive labelled nitrogen (N15). Results show that cell design plays a key role, and the partial substitution of an abundant material (Fe) brings benefits, compared with the common noble metals reported in the literature. Furthermore, this contribution identifies the critical aspects to be addressed, emphasizing the need for breakthroughs to enhance performance in this highly challenging process.