Bio-Inspired Aerobic-Hydrophobic Janus Interface on Partially Carbonized Iron Heterostructure Promotes Bifunctional Nitrogen Fixation.

Overwhelming competition from hydrogen/oxygen evolution reactions and low solubility of N2 in aqueous systems drain on selectivity and activity on nitrogen fixation reaction. Herein, we design an aerobic-hydrophobic Janus structure by introducing fluorinated modification on porous carbon nanofibers embedded with partially carbonized iron heterojunctions (Fe3C/Fe@PCNF-F). The simulations prove that the Janus structure can keep the internal Fe3C/Fe@PCNF-F away from water infiltration and endow a N2 molecule-concentrating effect, suppressing the competing reactions and overcoming the mass-transfer limitations to build a robust "quasi-solid-gas" state micro-domain around the catalyst surface. In this proof-of-concept system, the Fe3C/Fe@PCNF-F exhibits excellent electrocatalytic performance for nitrogen fixation (NH3 yield rate up to 29.2 μg h-1 mg-1cat. and Faraday efficiency (FE) up to 27.8% in NRR; NO3- yield rate up to 15.7 μg h-1 mg-1cat. and FE up to 3.4 % in NOR).