CO2 reduction in a microchannel electrochemical reactor with gas-liquid segmented flow
CO2 reduction in a microchannel electrochemical reactor with gas-liquid segmented flow
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DOI：
10.1016/j.cej.2020.124798
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发表时间：
2020-07
影响因子：
15.1
通讯作者：
Fanghua Zhang;Chengzhen Chen;Yanling Tang;Zhenmin Cheng
中科院分区：
文献类型：
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作者：
Fanghua Zhang;Chengzhen Chen;Yanling Tang;Zhenmin Cheng
在高电流密度下，由于催化剂表面二氧化碳浓度较低，电化学还原CO2受到传质限制。为了强化传质，建立了一种新型的环形微通道电化学反应器，该反应器由圆柱形阳离子交换膜和中间的氧化物泡沫铜电极组成。结果表明，由于CO2在通道内的气液传质增强，使极限电流密度从6.7mA/cm−2提高到10.0 mA/cm−2，极限电流密度从21.5×10−9mol和S−1 cm−2提高到33.4×10−9mol和S−1 cm−2，CO2还原率提高了55.3%。极限电流密度受环空流道宽度和气液比的影响，当气液比为2：1时，流道宽度为1 mm时性能最好。这表明利用微流道强化电化学法有效还原二氧化碳的传质潜力很大。
Electrochemical CO2reduction is suffered from mass transfer limitation at high current densities, owing to the low carbon dioxide concentration over the surface of the catalyst. To enhance mass transfer, a novel annular microchannel electrochemical reactor was established, which consists of a cylindrical cation exchange membrane at the outside and an oxide-derived Cu foam rod as the electrode in the middle. The results show that, due to the enhanced gas–liquid mass transfer of CO2in the channel, the limiting current density can increase by 49.3% from 6.7 mA cm−2to 10.0 mA cm−2and CO2reduction rate increase by 55.3% from 21.5 × 10−9mol s−1cm−2to 33.4 × 10−9mol s−1cm−2, compared when Cu electrode is in the open space. It further shows the limiting current density is influenced by the annulus channel width and gas–liquid ratio, and width of 1 mm gives the best performance at a gas–liquid ratio of 2:1. This work demonstrates the great potential of utilizing microchannel to intensify the mass transfer for efficient electrochemical CO2reduction.