Kinetics of formic acid dehydration on Pt electrodes by time-resolved ATR-SEIRAS

• Published in: The Journal of chemical physics Vol. 158; no. 9; pp. 094705 - 94712
• Main Authors: Pérez-Martínez, Laura, Herrero, Enrique, Cuesta, Angel
• Format: Journal Article
• Language: English
• Published: United States 07.03.2023
• ISSN: 0021-9606; 1089-7690
• DOI: 10.1063/5.0138791

The potential dependence of the rate of dehydration of formic acid to adsorbed CO (COad) on Pt at pH 1 has been studied on a polycrystalline Pt surface by time-resolved surface-enhanced infrared absorption spectroscopy in the attenuated total reflection mode (ATR-SEIRAS) with simultaneous recording of current transients after a potential step. A range of formic acid concentrations has been used to obtain a deeper insight into the mechanism of the reaction. The experiments have allowed us to confirm that the potential dependence of the rate of dehydration has a bell shape, going through a maximum around the potential of zero total charge (pztc) of the most active site. The analysis of the integrated intensity and frequency of the bands corresponding to COL and COB/M shows a progressive population of the active sites on the surface. The observed potential dependence of the rate of formation of COad is consistent with a mechanism in which the reversible electroadsorption of HCOOad is followed by its rate-determining reduction to COad.