Multiple state-of-the-art tools used to investigate methanol and formic acid electrooxidation
DOI: 10.1063/10.0009369
Multiple state-of-the-art tools used to investigate methanol and formic acid electrooxidation lead image
Formic acid and methanol are candidate fuels for fuel cell applications. While the electrochemical oxidation on platinum electrodes has been extensively studied, Wang and Abruña provided detailed, original mechanistic insights into these systems.
Electrochemistry combined with differential electrochemical mass spectrometry, DEMS, and attenuated total reflection-surface enhanced infrared absorption spectroscopy, ATR-SEIRAS, were used to determine various intermediate species produced during the electrochemical oxidation of these small organic molecules.
“We were able to characterize the oxidation of formic acid and methanol in terms of potential dependent surface adsorbed species, product distributions, yields and coulometric efficiencies,” said co-author Héctor Abruña.
A platinum film electrode was exposed to a dilute perchloric acid solution containing methanol or formic acid and evaluated via the combined system. Carbon dioxide and methyl formate were detected by DEMS. Adsorbed carbon monoxide, formate, formic acid, and the formyl radical, CHO, were identified using ATR-SEIRAS.
Modifying the electrode with a sub-monolayer of lead significantly enhanced formic acid oxidation and slightly increased the successive oxidation of adsorbed carbon monoxide to carbon dioxide, the terminal oxidation product. The researchers also found that the thickness and morphology of the platinum film can affect the infrared bands formed during methanol and formic acid oxidation.
“We feel that this work will serve as an example of how to unravel the mechanisms involved in the oxidation of small organic molecules such as formic acid and methanol,” said Abruña.
Future work will focus on the mechanistic study of ethanol electrooxidation and carbon dioxide electroreduction.
Source: “New insights into methanol and formic acid electro-oxidation on Pt: simultaneous DEMS and ATR-SEIRAS study under well-defined flow conditions and simulations of CO spectra,” by Hongsen Wang, and Héctor D. Abruña, Journal of Chemical Physics (2022). The article can be accessed at https://doi.org/10.1063/5.0071463 .
This paper is part of The Chemical Physics of the Electrode-Electrolyte Interface Collection, learn more here .
