Low‐Coordinated Single‐Atom Catalysts Modulated by Metal Ionic Liquids for Efficient CO2 Electroreduction

• Published in: Advanced functional materials 2023-11, Vol.33 (47), p.n/a
• Main Authors: Yuan, Lei, Zeng, Shaojuan, Li, Guilin, Wang, Yaofeng, Peng, Kuilin, Feng, Jiaqi, Zhang, Xiangping, Zhang, Suojiang
• Format: Article
• Language: English
• Subjects: Carbon dioxide; Catalysts; Catalytic activity; CO2 electroreduction; coordination environment; Electronic structure; Electrowinning; Free energy; Ionic liquids; Materials science; metal ionic liquids; Precursors; Pyrolysis; single‐atom catalysts; Synthesis; Transition metals
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202306994

Modulating the coordination environment of single‐atom catalysts (SACs) is an attractive approach for maximizing the catalytic activity of single‐atom centers. Currently, the synthesis of low‐coordinated SACs is mainly confined to increasing the pyrolysis temperature (≥900 °C) to control C─N volatile fragments. Herein, a novel and universal strategy for the low‐coordinated SACs modulation is presented using transition metal (e.g., Ni, Co, Zn) ionic liquid precursors under relatively mild temperature of 600 °C, which regulates the L‐shell electronic structure and decreases nearly 50% electrophilic reactivity by ionization of 4‐position N atom, thereby orienting synthesis of the SACs with metal‐N3 centers. The Ni‐N3 SACs exhibit exceptional CO2 electroreduction performance of 99.7% CO Faraday efficiency with an ultra‐high CO partial current density of 467.55 mA·cm−2 as well as a CO production rate up to 10417.51 µmol·h−1·cm−2 in flow cell. The superior catalytic activity achieves over twofold increase compared with the Ni‐N4 SACs prepared by non‐metal ionic liquid precursors due to the lower free energy of the key intermediate *COOH and the stronger adsorption energy. A universal metal ionic liquid precursors (MILPs) strategy is proposed for the synthesis of metal (M)‐N3 single–atom catalysts. The Ni–N3–C exhibits exceptional performance of 99.7% CO Faraday efficiency with an ultra–high partial current density of 467.55 mA·cm−2 in flow cell, achieving over twofold increase compared with the Ni–N4–C prepared by non‐MILPs.