The Conventional Gas Diffusion Electrode May Not Be Resistant to Flooding during CO 2 /CO Reduction
The Conventional Gas Diffusion Electrode May Not Be Resistant to Flooding during CO 2 /CO Reduction
复制标题
传统的气体扩散电极在CO 2 /CO还原过程中可能不耐溢流
DOI：
10.1149/1945-7111/ac9b96
复制
发表时间：
2022
影响因子：
3.9
通讯作者：
Shanov, Vesselin N.
中科院分区：
文献类型：
--
作者：
Zhang, Tianyu;Li, Zhengyuan;Lyu, Xiang;Raj, Jithu;Zhang, Guangqi;Kim, Hyunsik;Wang, Xiangning;Chae, Soryong;Lemen, Lisa;Shanov, Vesselin N.
利用可再生能源将二氧化碳或一氧化碳电化学还原为化学品和燃料是一种很有前途的减少人为碳排放的方法。气体扩散电极设计能够在符合工业要求的电流密度(例如，500 mA cm−2)下低碳制造目标产品。然而，GDE的长期稳定性受到水管理不善和洪水的限制，导致在近一小时内发生了显著的析氢反应(HER)。GDE中水管理的优化需要对气体扩散层(GDL)和催化层(CL)的作用有明确的认识。在这里，分别调节GDL和CL的疏水性，以考察它们对气体输送效率和水管理的影响。气体输运效率随GDL疏水性的增加比CL的提高更明显。光学显微镜和微计算机层析成像对水分布的直观显示表明，随着GDL疏水性的增加，水的流动模式从稳定的驱替向毛细指进转变。不幸的是，仅仅增加疏水性并不足以防止水淹。GDE结构设计的革命性变化对于保持CO2/CO还原的长期稳定性是必不可少的。
The electrochemical CO 2 or CO reduction to chemicals and fuels using renewable energy is a promising way to reduce anthropogenic carbon emissions. The gas diffusion electrode (GDE) design enables low-carbon manufacturing of target products at a current density (eg, 500 mA cm− 2) relevant to industrial requirements. However, the long-term stability of the GDE is restricted by poor water management and flooding, resulting in a significant hydrogen evolution reaction (HER) within almost an hour. The optimization of water management in the GDE demands a thorough understanding of the role of the gas diffusion layer (GDL) and the catalyst layer (CL) distinctively. Herein, the hydrophobicity of the GDL and CL is independently adjusted to investigate their influence on gas transport efficiency and water management. The gas transport efficiency is more enhanced with the increase in hydrophobicity of the GDL than the CL. Direct visualization of water distribution by optical microscope and micro-computed tomography demonstrates that the water flow pattern transfers from the stable displacement to capillary fingering as GDL hydrophobicity increases. Unfortunately, only increasing the hydrophobicity is not sufficient to prevent flooding. A revolutionary change in the design of the GDE structure is essential to maintain the long-term stability of CO 2/CO reduction.