High-performance artificial nitrogen fixation at ambient conditions using a metal-free electrocatalyst

• Published in: Nature communications Vol. 9; no. 1; pp. 3485 - 8
• Main Authors: Qiu, Weibin, Xie, Xiao-Ying, Qiu, Jianding, Fang, Wei-Hai, Liang, Ruping, Ren, Xiang, Ji, Xuqiang, Cui, Guanwei, Asiri, Abdullah M., Cui, Ganglong, Tang, Bo, Sun, Xuping
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 28.08.2018; Nature Publishing Group; Nature Portfolio
• Subjects: 140/131; 140/133; 140/146; 147/135; 147/143; 639/301/299/161; 639/638/77/886; Ammonia; Boron; Boron carbide; Catalysis; Catalysts; Chemical reduction; Density functional theory; Electrocatalysts; Electrochemistry; Humanities and Social Sciences; Hydrogen-based energy; multidisciplinary; Nitrogen; Nitrogen fixation; Organic chemistry; Science; Science (multidisciplinary); Stability analysis
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-018-05758-5

Conversion of naturally abundant nitrogen to ammonia is a key (bio)chemical process to sustain life and represents a major challenge in chemistry and biology. Electrochemical reduction is emerging as a sustainable strategy for artificial nitrogen fixation at ambient conditions by tackling the hydrogen- and energy-intensive operations of the Haber–Bosch process. However, it is severely challenged by nitrogen activation and requires efficient catalysts for the nitrogen reduction reaction. Here we report that a boron carbide nanosheet acts as a metal-free catalyst for high-performance electrochemical nitrogen-to-ammonia fixation at ambient conditions. The catalyst can achieve a high ammonia yield of 26.57 μg h –1  mg –1 cat. and a fairly high Faradaic efficiency of 15.95% at –0.75 V versus reversible hydrogen electrode, placing it among the most active aqueous-based nitrogen reduction reaction electrocatalysts. Notably, it also shows high electrochemical stability and excellent selectivity. The catalytic mechanism is assessed using density functional theory calculations. Electrochemical reduction of nitrogen is a promising route to industrial-scale nitrogen fixation at ambient conditions, but is challenged by activation of inert nitrogen. Here the authors report a metal-free catalyst that selectively reduces nitrogen to ammonia with high efficiency and stability.