Electrochemical nitrogen reduction reaction (NRR) is a promising method for energy-efficient and low-emission NH3 production. Herein, we report electrochemical NH3 production using a copper sulfide-based electrocatalyst. A solid-state synthesis is employed to prepare the Cu9S5 catalyst for artificial N2 fixation in a neutral aqueous electrolyte. Despite an excellent NRR activity of 10.8 ± 0.4 μg/hcm2 at -0.5 VRHE, however, the catalyst itself is reductively degraded during the NRR. To achieve continuous electrochemical NH3 production, a regenerative electrochemical sulfur cycle is introduced that revives the Cu9S5 crystal structure and NRR activities. The electrochemical regeneration process reconstructing the metal-sulfur bond in between sequential NH3 production processes restores the NRR activity. Importantly, catalytic surfaces providing a labile sulfhydryl functional group attached to the N2-adsorption metal center are required to achieve efficient NRR activity under ambient conditions.
|Number of pages||11|
|Publication status||Published - 2021 Jan 1|
Bibliographical noteFunding Information:
We thank Dr. Jeongjae Lee (Seoul National University) for help with the NMR analysis. This work was supported by the Creative Materials Discovery Program through the National Research Foundation of Korea (NRF-2016M3D1A1021140) and the Korea Institute of Science and Technology (Grant nos. 2V07940 and 2E30380). This work was also supported by the NRF grant funded by the Korea government (MSIT) (2018M1A2A2061975, 2019R1A2B5B03004854).
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