Ammonia-Mediated CO2 Capture and Direct Electroreduction to Formate
Ammonia-Mediated CO2 Capture and Direct Electroreduction to Formate
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DOI：
10.1021/acsenergylett.2c02247
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发表时间：
2022-11
影响因子：
22
通讯作者：
Hengzhou Liu;Yifu Chen;Jungkuk Lee;Shuang Gu;Wenzheng Li
中科院分区：
文献类型：
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作者：
Hengzhou Liu;Yifu Chen;Jungkuk Lee;Shuang Gu;Wenzheng Li
将 CO2 捕获溶液（而不是气态 CO2）直接电化学转化为有价值的化学品可以绕过能源密集型的 CO2 再生和加压步骤，但此类过程的性能受到 CO2 释放缓慢和耗能双极膜 (BPM) 的使用的限制。在此，我们发现碳酸氢铵 (NH4HCO3) 电解槽优于最先进的 KHCO3 电解槽，很大程度上是因为其良好的热分解特性，通过用阴离子交换膜替代 BPM，可以将原位 CO2 浓度提高 3 倍，甲酸法拉第效率最大提高 23%，并且电池电压降低 35% （AEM）。然后，我们展示了一种将 NH4HCO3 电解与硝酸盐电解还原现场产生的氨捕获 CO2 相结合的集成工艺，其特点是 CO2 捕获剂的利用率高达 99.8%。这种多用途工艺为同时去除氮废物和简化二氧化碳捕获和升级提供了一条可持续的途径。
Direct electrochemical conversion of CO2capture solutions (instead of gaseous CO2) to valuable chemicals can circumvent the energy-intensive CO2regeneration and pressurization steps, but the performance of such processes is limited by the sluggish release of CO2and the use of energy-consuming bipolar membranes (BPMs). Herein, we discovered that an ammonium bicarbonate (NH4HCO3)-fed electrolyzer outperforms the state-of-the-art KHCO3electrolyzers largely because of its favorable thermal decomposition property, which allows for a 3-fold increase in thein situCO2concentration, a maximum 23% increase in formate faradaic efficiency, and a 35% reduction in cell voltage by substituting BPM with an anion exchange membrane (AEM). We then demonstrated an integrated process by combining NH4HCO3electrolysis with CO2capture by on-site generated ammonia from the electroreduction of nitrate, which features a remarkable 99.8% utilization of of CO2capturing agent. Such a multipurpose process offers a sustainable route for the simultaneous removal of N wastes and streamlined CO2capturing and upgrading.