Shih Ming-Chi, Jhang Ren-Huai, Tsai Ya-Ting, Huang Chia-Wei, Hung Yung-Jr, Liao Mei-Yi, Huang Jiaxing, Chen Chun-Hu
Department of Chemistry, National Sun Yat-sen University, Kaohsiung, 80424, Taiwan.
Department of Materials Science and Engineering, Northwestern University, Evanston, IL, 60208, USA.
Small. 2019 Dec;15(50):e1903363. doi: 10.1002/smll.201903363. Epub 2019 Oct 14.
Thin film electrocatalysts allow strong binding and intimate electrical contact with electrodes, rapid mass transfer during reaction, and are generally more durable than powder electrocatalysts, which is particularly beneficial for gas evolution reactions. In this work, using cobalt manganese oxyhydroxide, an oxygen evolution reaction (OER) electrocatalyst that can be grown directly on various electrodes as a model system, it is demonstrated that breaking a continuous film into discontinuous patches can significantly enhance the overall OER performance without sacrificing long-term stability even under elevated electrocatalytic stress. Discontinuous films with higher edge-to-area ratios exhibits reduced overpotentials, increased turnover frequency, and more pronounced current increase after electrochemical conditioning. Operando Raman spectroscopy studies during electrocatalysis reveal that the film edges require lower potential barrier for activation. Introducing discontinuity into thin film electrocatalysis can thus lead to the realization of high performance yet highly robust systems for harsh gas evolution reactions.
薄膜电催化剂能够与电极实现强结合和紧密的电接触，在反应过程中实现快速传质，并且通常比粉末电催化剂更耐用，这对于析气反应尤为有利。在这项工作中，使用可以直接生长在各种电极上的析氧反应（OER）电催化剂羟基氧化钴锰作为模型系统，结果表明，将连续薄膜破碎成不连续的斑块可以显著提高整体OER性能，即使在升高的电催化应力下也不会牺牲长期稳定性。具有更高边面积比的不连续薄膜表现出更低的过电位、更高的周转频率以及在电化学预处理后更明显的电流增加。电催化过程中的原位拉曼光谱研究表明，薄膜边缘激活所需的势垒更低。因此，在薄膜电催化中引入不连续性可以实现用于苛刻析气反应的高性能且高度稳健的系统。
