Broadband Sum-Frequency Generation Spectroscopic Invstigations of Thiocyanate on Polycrystalline Au Electrode in Alkaline Solutions

Authors

Mei XU, State Key Laboratory of Physical Chemistry of Solid Surfaces, The MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian, China;
Jing-jing WANG, State Key Laboratory of Physical Chemistry of Solid Surfaces, The MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian, China;
Zhi-chao HUANGFU, State Key Laboratory of Physical Chemistry of Solid Surfaces, The MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian, China;
NG Ying WA, State Key Laboratory of Physical Chemistry of Solid Surfaces, The MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian, China;
Yu-han HE, State Key Laboratory of Physical Chemistry of Solid Surfaces, The MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian, China;
Zhao-hui WANG, State Key Laboratory of Physical Chemistry of Solid Surfaces, The MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian, China;Follow

Corresponding Author

Zhao-hui WANG(zhwang@xmu.edu.cn)

Abstract

Broadband sum frequency generation (BB-SFG) spectroscopy has been used to investigating the potential-dependent adsorption behaviors of thiocyanate ions on polycrystalline Au electrode in alkaline solutions. During the positive scan, a change in the Stark slope (dω_C-N/dE) for C—N stretching mode can be observed in the range of -1.1 V ~ 0.2 V (vs. SCE), which implies that the orientation of adsorbed thiocyanate ions at Au electrode surface changes from N-bound (dω_C-N/dE=45 cm^-1·V^-1) form to S-bound (dω_C-N/dE = 16.2 cm^-1·V^-1) form . At more positive potentials, the electrons in Au are ongoing interband transition, from d-band to sp-band, instead of intraband transition, from sp-band to sp-band, during the SFG process, and this difference will change the relative phase between the substrate and the adsorbed SCN- SFG signals. As a consequence, when the applied potential is more positive, the lineshapes of the BB-SFG spectrum for C—N stretching mode become Fano (dispersive) lineshapes. From the potential-dependent BB-SFG lineshapes, the information about relative positions for the electric energy levels of the electrode surface can be obtained.

Graphical Abstract

Keywords

broadband sum frequency generation, Au electrode, thiocyanate ion, alkaline solution

DOI Link

https://doi.org/10.13208/j.electrochem.150413

Publication Date

2015-08-28

Online Available Date

2015-08-28

Revised Date

2015-04-30

Received Date

2015-04-13

Recommended Citation

Mei XU, Jing-jing WANG, Zhi-chao HUANGFU, NG Ying WA, Yu-han HE, Zhao-hui WANG. Broadband Sum-Frequency Generation Spectroscopic Invstigations of Thiocyanate on Polycrystalline Au Electrode in Alkaline Solutions[J]. Journal of Electrochemistry, 2015 , 21(4): 319-325.
DOI: 10.13208/j.electrochem.150413
Available at: https://jelectrochem.xmu.edu.cn/journal/vol21/iss4/3