The built-in electric field across FeN/Fe<sub>3</sub>N interface for efficient electrochemical reduction of CO<sub>2</sub> to CO.

Yin, Jie; Jin, Jing; Yin, Zhouyang; Zhu, Liu; Du, Xin; Peng, Yong; Xi, Pinxian; Yan, Chun-Hua et al. · Nat Commun · 2023

basic_science · Level V

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Abstract

Nanostructured metal-nitrides have attracted tremendous interest as a new generation of catalysts for electroreduction of CO<sub>2</sub>, but these structures have limited activity and stability in the reduction condition. Herein, we report a method of fabricating FeN/Fe<sub>3</sub>N nanoparticles with FeN/Fe<sub>3</sub>N interface exposed on the NP surface for efficient electrochemical CO<sub>2</sub> reduction reaction (CO<sub>2</sub>RR). The FeN/Fe<sub>3</sub>N interface is populated with Fe-N<sub>4</sub> and Fe-N<sub>2</sub> coordination sites respectively that show the desired catalysis synergy to enhance the reduction of CO<sub>2</sub> 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<sub>3</sub>N synergy arises from electron transfer from Fe<sub>3</sub>N to FeN and the preferred CO<sub>2</sub> 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<sub>2</sub>RR.