Ionic Liquids Modulating Local Microenvironment of Ni–Fe Binary Single Atom Catalyst for Efficient Electrochemical CO2 Reduction

• Published in: Small (Weinheim an der Bergstrasse, Germany) Vol. 20; no. 24; pp. e2308522 - n/a
• Main Authors: Sun, Jiale, Liu, Zhen, Zhou, Haihui, Cao, Mengxue, Cai, Weiming, Xu, Chenxi, Xu, Junwei, Huang, Zhongyuan
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01-06-2024
• Subjects: Anions; Carbon dioxide; Current density; electrochemical CO2 reduction; Electronic structure; Electrons; Intermetallic compounds; Ionic liquids; Iron; Iron compounds; micro‐surface modulation; Nickel compounds; NiFe‐N‐C; Nitrogen; Single atom catalysts; Zn‐CO2 batteries
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.202308522

The Ni and Fe dual‐atom catalysts still undergo strikingly attenuation under high current density and high overpotential. To ameliorate the issue, the ionic liquids with different cations or anions are used in this work to regulate the micro‐surface of nitrogen‐doped carbon supported Ni and Fe dual‐atom sites catalyst (NiFe‐N‐C) by an impregnation method. The experimental data reveals the dual function of ionic liquids, which enhances CO2 adsorption ability and modulates electronic structure, facilitating CO2 anion radical (CO2•¯) stabilization and decreasing onset potential. The theoretical calculation results prove that the attachment of ionic liquids modulates electronic structure, reduces energy barrier of CO2•¯ formation, and enhances overall ECR performance. Based on these merits, BMImPF6 modified NiFe‐N‐C (NiFe‐N‐C/BMImPF6) achieves the high CO faradaic efficiency of 91.9% with a CO partial current density of −120 mA cm−2 at −1.0 V. When the NiFe‐N‐C/BMImPF6 is assembled as cathode of Zn‐CO2 battery, it delivers the highest power density of 2.61 mW cm−2 at 2.57 mA cm−2 and superior cycling stability. This work will afford a direction to modify the microenvironment of other dual‐atom catalysts for high‐performance CO2 electroreduction.
The ionic liquids with different cations or anions are used to regulate the micro‐surface of nitrogen‐doped carbon supported Ni and Fe dual‐atom sites catalyst (NiFe‐N‐C) by an impregnation method, which can enhance CO2 adsorption ability, modulate electronic structure, reduce energy barrier of CO2•¯ formation and promote overall ECR performance.