Decoupled hydrogen and oxygen evolution by a two-step electrochemical-chemical cycle for efficient overall water splitting
Decoupled hydrogen and oxygen evolution by a two-step electrochemical-chemical cycle for efficient overall water splitting
复制标题
DOI：
10.1038/s41560-019-0462-7
复制
发表时间：
2019-09-01
期刊：
影响因子：
56.7
通讯作者：
Grader, Gideon S.
中科院分区：
文献类型：
--
作者：
Dotan, Hen;Landman, Avigail;Grader, Gideon S.
电解制氢面临着提高其效率、经济价值和全球一体化潜力的技术挑战。在传统的水电解中，水的氧化和还原反应在时间和空间上都是耦合的，因为它们同时发生在同一电池中的阳极和阴极处。这带来了挑战，例如产品分离，并对材料选择和工艺条件设置了严格的限制。在这里，我们通过将该过程分为两个步骤来解耦这些反应：一个电化学步骤，减少阴极处的水并氧化阳极，然后是一个自发的化学步骤，在较高的温度下驱动得更快，通过氧化水将阳极还原到其初始状态。这使得在无膜双电极电池中，在1.44-1.60 V的平均电池电压和10-200 mA cm（-2）的标称电流密度下能够进行总体水裂解。这使我们能够在低电压下以简单的循环过程生产氢气，具有高效，稳健，安全和放大潜力。
Electrolytic hydrogen production faces technological challenges to improve its efficiency, economic value and potential for global integration. In conventional water electrolysis, the water oxidation and reduction reactions are coupled in both time and space, as they occur simultaneously at an anode and a cathode in the same cell. This introduces challenges, such as product separation, and sets strict constraints on material selection and process conditions. Here, we decouple these reactions by dividing the process into two steps: an electrochemical step that reduces water at the cathode and oxidizes the anode, followed by a spontaneous chemical step that is driven faster at higher temperature, which reduces the anode back to its initial state by oxidizing water. This enables overall water splitting at average cell voltages of 1.44-1.60 V with nominal current densities of 10-200 mA cm(-2) in a membrane-free, two-electrode cell. This allows us to produce hydrogen at low voltages in a simple, cyclic process with high efficiency, robustness, safety and scale-up potential.