The built-in electric field across FeN/Fe(3)N interface for efficient electrochemical reduction of CO(2) to CO

Nanostructured metal-nitrides have attracted tremendous interest as a new generation of catalysts for electroreduction of CO(2), but these structures have limited activity and stability in the reduction condition. Herein, we report a method of fabricating FeN/Fe(3)N nanoparticles with FeN/Fe(3)N interface exposed on the NP surface for efficient electrochemical CO(2) reduction reaction (CO(2)RR). The FeN/Fe(3)N interface is populated with Fe−N(4) and Fe−N(2) coordination sites respectively that show the desired catalysis synergy to enhance the reduction of CO(2) to CO. The CO Faraday efficiency reaches 98% at −0.4 V vs. reversible hydrogen electrode, and the FE stays stable from −0.4 to −0.9 V during the 100 h electrolysis time period. This FeN/Fe(3)N synergy arises from electron transfer from Fe(3)N to FeN and the preferred CO(2) adsorption and reduction to *COOH on FeN. Our study demonstrates a reliable interface control strategy to improve catalytic efficiency of the Fe–N structure for CO(2)RR.