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Electroreduction Activity of Hydrogen Peroxide on Pt and Au Electrodes

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journal contribution
posted on 27.09.2005, 00:00 by Xiao Li, Dodi Heryadi, Andrew A. Gewirth
Hydrogen peroxide electroreduction on both catalytically active Pt and inactive Au surfaces are studied by using both surface-enhanced Raman spectroscopy (SERS) and density functional theory (DFT) calculations. SERS measurements on Pt show the presence of Pt−OH at negative potentials, which suggests that hydroxide is formed as an intermediate during the electroreduction process. Additionally, the O−O stretch mode of H2O2 is observed on Pt, which shifts to lower energy as potential is swept negatively, indicating that the O−O bond is elongated. For comparison, there is no variation in the energy of the same O−O mode on Au surfaces, and there is no observation of Au−OH. DFT calculations show that H2O2 adsorption on Pt(110) results in the dissociation of O−O bond and the formation of Pt−OH bond. On Au, O−O bond elongation is calculated to occur only on the (110) face. However, the magnitude of the elongation is much smaller than that found on Pt(110).