In-situ STM Visualization of Molecular Structural Evolution during Electrochemical Oxidation Coupling of Para-Aminothiophenol on Au(111)

Authors

• Zi-Wei Ma, State Key Laboratory of Physical Chemistry of Solid Surface, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, PR China.
• Tai-Rui Wu, State Key Laboratory of Physical Chemistry of Solid Surface, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, PR China.
• An-Ni Zheng, State Key Laboratory of Physical Chemistry of Solid Surface, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, PR China.
• Lai-Ke Chen, State Key Laboratory of Physical Chemistry of Solid Surface, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, PR China.
• Yuan-Hui Xiao, State Key Laboratory of Physical Chemistry of Solid Surface, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, PR China.
• Zhao-Bin Chen, State Key Laboratory of Physical Chemistry of Solid Surface, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, PR China.
• Qing-Na Zheng, State Key Laboratory of Physical Chemistry of Solid Surface, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, PR China.Follow
• Jian-Zhang Zhou, State Key Laboratory of Physical Chemistry of Solid Surface, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, PR China.Follow
• Jia-Wei Yan, State Key Laboratory of Physical Chemistry of Solid Surface, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, PR China.Follow
• De-Yin Wu, State Key Laboratory of Physical Chemistry of Solid Surface, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, PR China.Follow

Document Type

Article

Corresponding Author(s)

Qing-Na Zheng(zhengqn@xmu.edu.cn);
Jian-Zhang Zhou(jzzhou@xmu.edu.cn);
Jia-Wei Yan(jwyan@xmu.edu.cn);
De-Yin Wu(dywu@xmu.edu.cn)

Abstract

Para-aminothiophenol (PATP) is not only a widely-used probe molecule in the field of surface-enhanced Raman spectroscopy (SERS), but also an important model molecule for interfacial reactions, exhibiting distinct photo- and electro-oxidation pathways, so that PATP is selectively activated under different external fields. The evolution of products and intermediates during electrochemical oxidative coupling remains unknown. In this study, we have investigated the dynamic electrochemical oxidation process of PATP on the Au(111) surface using cyclic voltammetry, EC-SERS, and in situ electrochemical scanning tunneling microscopy (EC-STM). The results show that PATP forms unsaturated adsorption coverage on Au(111) in acidic solution. When the potential is positively shifted to the oxidation potential range, the cation radical generated by PATP oxidation alternate with PATP molecules in arrangement. Once the coupling reaction occurs, the adsorption structure of alternating arrangement is transformed into stripe structure in STM images. Finally, the coverage on Au(111) decreases and a √¯3 × 4√¯6. structure is formed. The oxidation reaction product 4′-mercapto-N-phenylquinone diimine (NPQD) adopts the arrangement of mixed adsorption sites of bridge and hollow sites on Au(111). By determining the adsorption structure evolution of PATP during the electrooxidation process on the gold surface, the mechanism of interfacial electrochemical oxidation coupling reaction is revealed from a spatial perspective. This lays the foundation for further modulation and design of the interfacial reaction of aromatic amine molecules.

Graphical Abstract

Keywords

In-situ electrochemical scanning tunneling microscopy (In-situ EC-STM), Para-aminothiophenol (PATP), 4'-mereapto-N-phenylquinone diimine (NPQD), Electrochemical surface-enhanced Raman spectroscopy (EC-SERS)

DOI

10.61558/2993-074X.3614

Online Date

5-9-2026

Recommended Citation

Zi-Wei Ma, Tai-Rui Wu, An-Ni Zheng, Lai-Ke Chen, Yuan-Hui Xiao, Zhao-Bin Chen, Qing-Na Zheng, Jian-Zhang Zhou, Jia-Wei Yan, De-Yin Wu. In-situ STM Visualization of Molecular Structural Evolution during Electrochemical Oxidation Coupling of Para-Aminothiophenol on Au(111)[J]. Journal of Electrochemistry, doi: 10.61558/2993-074X.3614.