Infrared spectroscopy of adsorbed OH on n(111)–(100) and n(111)–(111) series of Pt electrode

Abstract

Infrared spectroscopy of adsorbed hydroxide (OHad) has been performed on the high index planes of Pt: n(111)–(100) and n(111)–(111) series. The bending mode of OHad (δPtOH) appears on these surfaces around 1080cm−1, which is similar to the result on the low index planes of Pt. The band intensity of δPtOH depends on surface structure and electrode potential. At 0.9V vs RHE, the band intensity of δPtOH increases with the decrease of the step atom density: the intensity of δPtOH is higher on the surfaces with lower activity of the oxygen reduction reaction (ORR). These results suggest that the adsorption of OHad is site specific and the deactivating species of the ORR.