通过被动化层对MgO的装甲阻碍了CO2的直接空气捕获
Juliane Weber1, Vitalii Starchenko1, Ke Yuan1
1Chemical Science Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States.
Environmental science & technology
|September 22, 2023
概括
氧化 (MgO) 对直接捕获二氧化碳 (CO2) 的空气表现有希望. 然而,实验表明,表面被动化显著减缓了反应,限制了它在大规模二氧化碳去除方面的有效性.
科学领域:
- 材料科学 材料科学 材料科学
- 环境科学 环境科学
- 化学工程是化学工程的重要组成部分.
背景情况:
- 氧化 (MgO) 是用于捕获大气中的二氧化碳 (CO2) 的候选材料.
- 了解MgO反应动力学对于评估其在直接空气捕获 (DAC) 技术中的潜力至关重要.
研究的目的:
- 研究氧化 (MgO) 与大气中的二氧化碳 (CO2) 在不同时间尺度上的反应速率.
- 为了确定限制基于MgO的二氧化碳捕获效率的因素.
主要方法:
- 实验分析MgO单晶与大气反应的时间从几天到几十年不等.
- 使用显微镜和光谱技术对反应产品和表面形态进行表征.
- 在长期暴露的MgO样本中分析反应层厚度.
主要成果:
- 观察到MgO的初始快速化和碳化,形成无形和结晶的碳酸盐.
- 随着时间的推移,由于表面被反应产品 (矿物装甲) 被动化,反应速率大幅下降.
- 对27年历史的MgO样本的分析显示,反应层厚度有限 (∼1.5μm),证实了显著的表面被动化.
结论:
- 表面被动化是使用MgO在直接空气捕获 (DAC) CO2的关键限制.
- 绕过表面被动化对于开发有效的基于MgO的二氧化碳捕获系统至关重要.
- 优化反应点密度,例如沿着原子步骤,可以增强碳化动力学.
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