Impact of Local Microenvironments on the Selectivity of Electrocatalytic Nitrate Reduction in a BPM‐MEA System
Impact of Local Microenvironments on the Selectivity of Electrocatalytic Nitrate Reduction in a BPM‐MEA System
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DOI：
10.1002/aenm.202304202
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发表时间：
2024-02
影响因子：
27.8
通讯作者：
Po-Wei Huang;Hakhyeon Song;Jaeyoung Yoo;Danae A. Chipoco Haro;Hyuck Mo Lee;Andrew J. Medford;Marta C. Hatzell
中科院分区：
文献类型：
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作者：
Po-Wei Huang;Hakhyeon Song;Jaeyoung Yoo;Danae A. Chipoco Haro;Hyuck Mo Lee;Andrew J. Medford;Marta C. Hatzell
电化学硝酸还原反应（NO3RR）作为一种将有害污染物（硝酸盐）转化为增值产品（氨）的途径，越来越受到人们的关注。然而，对氨（NH3）的高选择性是工艺可行性的必要条件。优化催化剂附近的质子可用性是实现选择性NH3生产的重要条件。在这里，目的是系统地研究质子可用性对双极膜（BPM）基膜电极组装（MEA）系统中NO3RR选择性的影响。在电解过程中，BPM从膜向催化剂产生质子通量。因此，BPM - MEA系统可以在运行过程中调节质子通量。还研究了中间层、质子清除电解质（CO32−）和催化剂构型的影响，以确定哪些局部微环境有利于氨的形成。研究发现，与标准MEA设置相比，适度的质子供应允许氨产量增加576%。这也导致了26 （NH3对NO2−）的高选择性，施加电流密度为200毫安厘米−2。
Electrochemical nitrate reduction reaction (NO3RR) has garnered increasing attention as a pathway for converting a harmful pollutant (nitrate) into a value‐added product (ammonia). However, high selectivity toward ammonia (NH3) is imperative for process viability. Optimizing proton availability near the catalyst is important for achieving selective NH3 production. Here, the aim is to systematically examine the impacts of proton availability on NO3RR selectivity in a bipolar membrane (BPM)‐based membrane electrode assembly (MEA) system. The BPM generates a proton flux from the membrane toward the catalyst during electrolysis. Thus, the BPM‐MEA system can modulate the proton flux during operation. The impact of interposer layers, proton scavenging electrolytes (CO32−), and catalyst configurations are also examined to identify which local microenvironments favor ammonia formation. It is found that a moderate proton supply allows for an increase in ammonia yield by 576% when compared to the standard MEA setup. This also results in a high selectivity of 26 (NH3 over NO2−) at an applied current density of 200 mA cm−2.