A combined surface-enhanced infrared and electrochemical kinetics study of hydrogen adsorption and evolution on a Pt electrode

In situ infrared spectroscopic and electrochemical study of hydrogen electro-oxidation on Pt electrode in sulfuric acid

“…Spectra are presented with an arbitrary offset. Similar to the case under inert atmosphere [28,29], an absorption band is observed around 2090 cm À1 . The band increases its intensity and shifts to the lower wavenumbers at less positive potentials.…”

“…A strong candidate for the intermediate is the adsorbed hydrogen detected by IRAS and ATR-SEIRAS around 2090 cm À1 in the previous reports [28,29], as discussed later. The overall reaction resistance r 0 and the exchange current density j 0 of hydrogen evolution/oxidation can be calculated from the slope of the j-E plots based on the relation:…”

“…It should be noted, however, that there has been in dispute about the structure-sensitivity of the kinetics of HER and HOR [8][9][10]22]; the effect of temperature and H 2 diffusion from the electrode surface is the main issue [8,22] [25,26] and SFG (Sum Frequency Generation) [27] could not fully support the earlier works [23,24], but our recent studies by ATR-SEIRAS (Attenuated-Total-Reflection Surface Enhanced Infrared Absorption Spectroscopy) [28,29] fully reproduced the data reported in [23,24] and showed that the intermediate is hydrogen which is adsorbed at atop sites on Pt and appears below 0.1V vs. RHE giving rise to Pt-H vibration around 2090 cm À1 . Coverage of this hydrogen species increases in the potential region below 0.1 V on Pt in addition to H UPD in the monolayer coverage.…”

Hydrogen adsorption and hydrogen evolution reaction on a polycrystalline Pt electrode studied by surface-enhanced infrared absorption spectroscopy

“…2). In our previous publication [22], the deviation was tentatively explained in terms of supersaturation effect of H 2 at the interface, which can give an apparent Tafel slope around 30 mV/decade independent of the mechanism [3,4,15,54,55].…”

“…In a recent study using surface-enhanced IR absorption spectroscopy (SEIRAS) with an attenuated total reflection (ATR) mode [22], we demonstrated that the IRAS study by Nichols and Bewick on polycrystalline Pt electrodes [16,17] is fully reproducible. It should be noted that the ATR-SEIRAS study was not a simple reinvestigation and differed from earlier vibrational spectroscopic studies regarding to two issues.…”