Folic Acid Self-Assembly Enabling Manganese Single-Atom Electrocatalyst for Selective Nitrogen Reduction to Ammonia

• Published in: Nano-micro letters 2021-12, Vol.13 (1), p.125-12, Article 125
• Main Authors: Wang, Xuewan, Wu, Dan, Liu, Suyun, Zhang, Jiujun, Fu, Xian-Zhu, Luo, Jing-Li
• Format: Article
• Language: English
• Subjects: Ammonia; Carbon; Chemical reduction; Density functional theory; Electrocatalysis; Electrocatalysts; Engineering; Folic acid; Folic acid self-assembly; Manganese; Manganese single-atom catalyst; N-doped carbon sheet; Nanoscale Science and Technology; Nanotechnology; Nanotechnology and Microengineering; Nitrogen; Nitrogen reduction; Selectivity; Self-assembly; Single atom catalysts; Synthesis; Vitamin B
• ISSN: 2311-6706; 2150-5551; 2150-5551
• DOI: 10.1007/s40820-021-00651-1

Highlights A manganese single-atom catalyst is developed via a facile folic acid self-assembly strategy. The catalyst exhibits outstanding activity and selectivity for electrochemical reduction of nitrogen to ammonia (NRR). Electrocatalytic mechanism of Mn–N 3 site for NRR is unveiled by a combination of experimental and computational study. Efficient and robust single-atom catalysts (SACs) based on cheap and earth-abundant elements are highly desirable for electrochemical reduction of nitrogen to ammonia (NRR) under ambient conditions. Herein, for the first time, a Mn–N–C SAC consisting of isolated manganese atomic sites on ultrathin carbon nanosheets is developed via a template-free folic acid self-assembly strategy. The spontaneous molecular partial dissociation enables a facile fabrication process without being plagued by metal atom aggregation. Thanks to well-exposed atomic Mn active sites anchored on two-dimensional conductive carbon matrix, the catalyst exhibits excellent activity for NRR with high activity and selectivity, achieving a high Faradaic efficiency of 32.02% for ammonia synthesis at  − 0.45 V versus reversible hydrogen electrode. Density functional theory calculations unveil the crucial role of atomic Mn sites in promoting N 2 adsorption, activation and selective reduction to NH 3 by the distal mechanism. This work provides a simple synthesis process for Mn–N–C SAC and a good platform for understanding the structure-activity relationship of atomic Mn sites. Graphic Abstract