Constructing a CoO–CuO x heterostructure for efficient electrochemical reduction of nitrate to ammonia

• Published in: Sustainable energy & fuels 2023-10, Vol.7 (20), p.5039-5045
• Main Authors: Tang, Yujun, Liu, Sanchuan, Guo, Chengyu, Liu, Yonggang, Tang, Zhenghua
• Format: Article
• Language: English
• ISSN: 2398-4902; 2398-4902
• DOI: 10.1039/D3SE01024D

The electrochemical nitrate reduction reaction (NtrRR) represents a sustainable approach to realize the green synthesis of ammonia, yet developing efficient electrocatalysts to improve the sluggish reaction kinetics and the undesirable selectivity towards NH 3 , while simultaneously suppressing the hydrogen evolution reaction (HER), is critical. Herein, we report a CoO–CuO x heterostructure catalyst that is prepared by in situ growing Cu(OH) 2 nanoarrays on Cu foam (CF), followed by hydrothermal treatment in the presence of a Co salt. Multiple characterizations revealed that a well-defined heterostructure with a distinct interface is formed between the CoO and CuO x phases. In the NtrRR test, the CoO–CuO x /CF catalyst displayed a high NH 3 selectivity of 94.29%, an NH 3 faradaic efficiency (FE NH 3 ) of 92.15%, and a high NH 3 yield rate of 0.510 mmol h −1 cm −2 . Also, the heterostructure catalyst had remarkable catalytic stability, evidenced by the negligible FE NH 3 decay after four consecutive cycling tests. This excellent catalytic performance is attributed to the fact that the interfaces in the CuO x and CoO heterostructure can facilitate the electron transfer, hence improving the reaction kinetics. This study offers a generic strategy for preparing efficient and durable electrocatalysts toward the NtrRR and other multiple electron/proton-involved electrocatalytic reactions.