Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
Nat Commun. 2020 May 8;11(1):2278. doi: 10.1038/s41467-020-16150-7.
Carbon capture is essential for mitigating carbon dioxide emissions. Compared to conventional chemical scrubbing, electrochemically mediated carbon capture utilizing redox-active sorbents such as quinones is emerging as a more versatile and economical alternative. However, the practicality of such systems is hindered by the requirement of toxic, flammable organic electrolytes or often costly ionic liquids. Herein, we demonstrate that rationally designed aqueous electrolytes with high salt concentration can effectively resolve the incompatibility between aqueous environments and quinone electrochemistry for carbon capture, eliminating the safety, toxicity, and at least partially the cost concerns in previous studies. Salt-concentrated aqueous media also offer distinct advantages including extended electrochemical window, high carbon dioxide activity, significantly reduced evaporative loss and material dissolution, and importantly, greatly suppressed competing reactions including under simulated flue gas. Correspondingly, we achieve continuous carbon capture-release operations with outstanding capacity, stability, efficiency and electrokinetics, advancing electrochemical carbon separation further towards practical applications.
碳捕集对于减少二氧化碳排放至关重要。与传统的化学洗涤相比，利用醌等氧化还原活性吸附剂的电化学介导碳捕集技术正成为一种更具通用性和经济性的替代方法。然而，由于需要有毒、易燃的有机电解质或通常昂贵的离子液体，此类系统的实用性受到了限制。在此，我们证明了通过合理设计高盐浓度的水相电解质，可以有效地解决水相环境与醌电化学碳捕集之间的不兼容性问题，消除了先前研究中的安全、毒性以及至少部分成本问题。盐浓度水相介质还具有明显的优势，包括扩展的电化学窗口、高二氧化碳活性、显著减少蒸发损失和材料溶解，以及重要的是，大大抑制了包括模拟烟道气中的竞争反应。相应地，我们实现了具有出色容量、稳定性、效率和电动动力学的连续碳捕集-释放操作，进一步推动电化学碳分离向实际应用发展。
