A Janus Fe‐SnO2 Catalyst Enables Bifunctional Electrochemical Nitrogen Fixation

Electrochemical N2 reduction reactions (NRR) and N2 oxidation reaction (NOR), using H2O and N2, represent a sustainable approach to N2 fixation and arouse widespread attention. To date, due to the chemical inertness of nitrogen, emerging electrocatalysts for the electrochemical NRR and NOR at room temperature and atmospheric pressure remain largely under explored. Herein, a new-type Fe-SnO2 was rationally designed as a Janus electrocatalyst for achieving highly efficient NRR and NOR catalysis. A high NH3 yield of 82.7 microg h-1 mgcat.-1 and a Faraday efficiency (FE) of 20.4% were obtained for NRR, superior than all noble-metal-free electrocatalysts reported in acid electrolyte. This catalyst can also serve as an excellent NOR electrocatalyst with a NO3- yields of 42.9 microg h-1 mgcat.-1 and a FE of 0.84%. By means of experiments and density functional theory (DFT) calculations, we reveal that the oxygen vacancy-anchored single-atom Fe can effectively adsorb and activate chemical inert N2 molecules, lower the energy barrier for the vital breakage of N identical withN, resulting in the enhanced N2 fixation performance.