Direct electroreduction of
CO
2
from simulated flue gas using ionic liquid electrolyte
Lei Yuan, Xin Feng, Kuilin Peng, Mingming Sun, Tingting Fan, Yuhan Wu, Shaojuan Zeng, Xiangping Zhang, Jianji Wang Abstract
Direct electroreduction of CO 2 from flue gas to high‐valued chemicals mitigates CO 2 emissions but suffers low product selectivity. Herein, an ionic liquid electrolyte consisting of 1‐butyl‐3‐methylimidazolium tetrafluoroborate ([C 4 mim][BF 4 ]), acetonitrile and H 2 O (5 wt%) was optimized for direct CO 2 electroreduction to CO (eCO 2 ‐to‐CO) from simulated flue gas. At −2.3 V (vs. Ag/Ag + ), the system delivers 95.6% CO Faradaic efficiency and 14.9 mA·cm −2 partial current density in H‐cell, representing one of the state‐of‐the‐art systems of low‐concentrated eCO 2 ‐to‐CO. Moreover, the existence of H 2 O improves electrolysis stability of the system from 5 to 150 h. In situ spectroscopy and computations revealed that H 2 O‐dissociated active H regenerates imidazolium C 2 ‐H sites of [C 4 mim][BF 4 ], lowering the energy barrier for *COOH formation. Techno‐economic assessment demonstrated a considerable reduction in CO production cost via direct eCO 2 ‐to‐CO from flue gas. This work is different from catalyst design and provides a novel solution for eCO 2 ‐to‐CO from flue gas using IL electrolyte strategy.