溶液中的CO2损失:用膜电极组装电池对CO2电解进行实验性研究
Weiming Liu1, Harry Dunne1, Bernardo Ballotta1
1School of Physics, Trinity College Dublin, Dublin D02 PN40, Ireland.
概括
二氧化碳 (CO2) 电解面临来自二氧化碳和碳酸盐离子的二氧化碳损失的挑战. 这项研究量化了二氧化碳的损失,揭示了低电流密度和高电流密度影响电解剂效率的不同机制.
科学领域:
- 电化学 电化学 电化学
- 化学工程是化学工程的重要组成部分.
- 材料科学 材料科学 材料科学
背景情况:
- 二氧化碳电解的商业可行性受到运营挑战的阻碍.
- 膜电极组件 (MEA) 类型的电解器是二氧化碳转换的关键.
- 电解质的二氧化碳损失作为二碳酸盐和碳酸盐离子是一个重大问题.
研究的目的:
- 调查MEA型二氧化碳电解器的运行挑战.
- 量化二氧化碳损失机制及其对电流密度的依赖.
- 分析离子形成在二氧化碳损失和电解仪性能中的作用.
主要方法:
- 使用银电极进行选择性二氧化碳转化为二氧化碳.
- 在电流密度 (0-600 mA/cm2) 上测量了CO2,CO和H2的摩尔产量.
- 通过电解质pH值变化和碳元素平衡分析监测CO2损失.
主要成果:
- 在低电流密度 (<125 mA/cm2) 时,二氧化碳损失 (高达0.18 mmol/min) 与氧化离子产生相关.
- 在高电流密度 (>450 mA/cm2) 时,二氧化碳损失停滞在0.12 mmol/min,这表明阴极被洪水淹没.
- 电解质pH值的变化表明了不同的离子群和穿过膜的运动.
结论:
- 在MEA电解器中,二氧化碳损失机制因电流密度而异.
- 氧化离子的生产在低电流密度下导致二氧化碳的损失.
- 电解质诱导的阴极泛滥限制了高电流密度的二氧化碳接入,影响了效率.
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