Abstract
The nature of formic acid adsorbates formed on porous platinum electrode has been studied by in-situ infrared reflectance spectroscopic (FTIR) and differential electrochemical mass spectroscopic (DEMS) techniques. By carefully avoiding the contamination of the environment (i.e ., air) voltammetric experiments show that the oxidation of formic acid adsorbates depends on both adsorption potential and adsorption time. The online DEMS results show furthermore that the number of electrons necessary for the formation of one molecule of CO2 from adsorbed formic acid is independent of the adsorption potential. Its value of 2.2 demonstrates that the composition of formic acid adsorbates is a mixture of CO and COH, but not CO or COH alone. The existence of these two species has been clearly proved by in-situ FTIR experiments on electrodeposited platinum with a roughness factor of 11. The bands at 1262 cm-1 , 1840 cm-1 , and in the frequency range of 2048 to 2060 cm-1 are due to the surface adsorbed COH, bridge and linearly bound COad, respectively.
In addition, the interaction between formic acid adsorbates and CO has been investigated by using DEMS via isotopic labelled 13C-formic acid as a probe as well. These experiments show that the surface species previously fromed from CO and formic acid cannot be exchanged by formic acid in solution. whereas about 75 percent of the firstly formed formic acid adsorbates can be replaced by bulk CO.
Keywords
Fomic acid, Adsorbates, Interaction, Porus Pt, In situ FTIR, DEMS
Publication Date
1997-02-28
Online Available Date
1997-02-28
Revised Date
1996-11-05
Received Date
1996-09-13
Recommended Citation
Xinhua Xia, Iwasita T., Vielstich W..
Study of the Nature of Formic Acid Adsorbates on Rough Pt and its Interaction with CO[J]. Journal of Electrochemistry,
1997
,
3(1): 26-39.
DOI: 10.61558/2993-074X.2649
Available at:
https://jelectrochem.xmu.edu.cn/journal/vol3/iss1/2
