Nitrogen reduction reaction to ammonia at ambient conditions: A short review analysis of the critical factors limiting electrocatalytic performance

The direct electrocatalytic production of ammonia (NH3) from N2 and H2O at ambient conditions is one of today's chemical challenges to meet the growing industrial demand for ammonia. Despite numerous studies on designing novel catalysts to activate N2 molecule and elucidating the reaction mechanism, many critical factors (such as gas diffusion and charge transfer limitations that instead promote the side reaction of hydrogen evolution) remain unsolved, suggesting that a breakthrough is needed to improve performance in this challenging reaction. Based on this, we review here recent studies that propose advanced solutions, focusing on: (i) the adoption of a three-dimensional nanoarchitecture of the electrode surface (to favour multi-electron transfer), (ii) the design of cell configuration (including the development of gas diffusion electrodes – GDEs), (iii) the critical aspects of the more efficient lithium-mediated approach in non-aqueous solvents (flooding of the GDE, sustainability of the proton-shuttle system), (iv) new methods for ammonia detection avoiding false positive.