Exploring the Cation Regulation Mechanism for Interfacial Water Involved in the Hydrogen Evolution Reaction by In Situ Raman Spectroscopy

Xueqiu You; Dongao Zhang; Xia-Guang Zhang; Xiangyu Li; Jing-Hua Tian; Yao-Hui Wang; Jian-Feng Li

doi:10.1007/s40820-023-01285-1

Exploring the Cation Regulation Mechanism for Interfacial Water Involved in the Hydrogen Evolution Reaction by In Situ Raman Spectroscopy

Nanomicro Lett. 2023 Dec 18;16(1):53. doi: 10.1007/s40820-023-01285-1.

Authors

Xueqiu You¹, Dongao Zhang², Xia-Guang Zhang³, Xiangyu Li¹, Jing-Hua Tian⁴, Yao-Hui Wang⁵, Jian-Feng Li^{6

7}

Affiliations

¹ School of Ocean Information Engineering, Fujian Provincial Key Laboratory of Oceanic Information Perception and Intelligent Processing, Jimei University, Xiamen, 361021, People's Republic of China.
² State Key Laboratory of Physical Chemistry of Solid Surfaces, MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, iChEM, College of Chemistry and Chemical Engineering, College of Materials, College of Energy, Xiamen University, Xiamen, 361005, People's Republic of China.
³ Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, College of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, 453007, People's Republic of China.
⁴ Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen, 361005, People's Republic of China.
⁵ State Key Laboratory of Physical Chemistry of Solid Surfaces, MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, iChEM, College of Chemistry and Chemical Engineering, College of Materials, College of Energy, Xiamen University, Xiamen, 361005, People's Republic of China. yaohuiwang@xmu.edu.cn.
⁶ State Key Laboratory of Physical Chemistry of Solid Surfaces, MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, iChEM, College of Chemistry and Chemical Engineering, College of Materials, College of Energy, Xiamen University, Xiamen, 361005, People's Republic of China. Li@xmu.edu.cn.
⁷ Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen, 361005, People's Republic of China. Li@xmu.edu.cn.

Abstract

Interfacial water molecules are the most important participants in the hydrogen evolution reaction (HER). Hence, understanding the behavior and role that interfacial water plays will ultimately reveal the HER mechanism. Unfortunately, investigating interfacial water is extremely challenging owing to the interference caused by bulk water molecules and complexity of the interfacial environment. Here, the behaviors of interfacial water in different cationic electrolytes on Pd surfaces were investigated by the electrochemistry, in situ core-shell nanostructure enhanced Raman spectroscopy and theoretical simulation techniques. Direct spectral evidence reveals a red shift in the frequency and a decrease in the intensity of interfacial water as the potential is shifted in the positively direction. When comparing the different cation electrolyte systems at a given potential, the frequency of the interfacial water peak increases in the specified order: Li⁺ < Na⁺ < K⁺ < Ca²⁺ < Sr²⁺. The structure of interfacial water was optimized by adjusting the radius, valence, and concentration of cation to form the two-H down structure. This unique interfacial water structure will improve the charge transfer efficiency between the water and electrode further enhancing the HER performance. Therefore, local cation tuning strategies can be used to improve the HER performance by optimizing the interfacial water structure.

Keywords: Cations; Hydrogen evolution reaction; In situ Raman; Interfacial water.