Shin Seung-Jae, Kim Dong Hyun, Bae Geunsu, Ringe Stefan, Choi Hansol, Lim Hyung-Kyu, Choi Chang Hyuck, Kim Hyungjun
Department of Chemistry, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea.
School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju, 61005, Republic of Korea.
Nat Commun. 2022 Jan 10;13(1):174. doi: 10.1038/s41467-021-27909-x.
To design electrochemical interfaces for efficient electric-chemical energy interconversion, it is critical to reveal the electric double layer (EDL) structure and relate it with electrochemical activity; nonetheless, this has been a long-standing challenge. Of particular, no molecular-level theories have fully explained the characteristic two peaks arising in the potential-dependence of the EDL capacitance, which is sensitively dependent on the EDL structure. We herein demonstrate that our first-principles-based molecular simulation reproduces the experimental capacitance peaks. The origin of two peaks emerging at anodic and cathodic potentials is unveiled to be an electrosorption of ions and a structural phase transition, respectively. We further find a cation complexation gradually modifies the EDL structure and the field strength, which linearly scales the carbon dioxide reduction activity. This study deciphers the complex structural response of the EDL and highlights its catalytic importance, which bridges the mechanistic gap between the EDL structure and electrocatalysis.
为设计用于高效电化学能量相互转换的电化学界面，揭示双电层（EDL）结构并将其与电化学活性相关联至关重要；尽管如此，这一直是一个长期存在的挑战。特别地，尚无分子水平的理论能完全解释双电层电容的电位依赖性中出现的特征双峰，而该电容敏感地依赖于双电层结构。我们在此证明，基于第一性原理的分子模拟再现了实验电容峰。揭示出在阳极和阴极电位处出现的两个峰的起源分别是离子的电吸附和结构相变。我们还发现阳离子络合逐渐改变双电层结构和场强，而场强与二氧化碳还原活性呈线性比例关系。本研究解读了双电层复杂的结构响应并突出了其催化重要性，弥合了双电层结构与电催化之间的机理差距。
