Currently, it is hard to detect adsorbed intermediates at such a low coverage. Nevertheless, Kondo et al. deduced from their in-situ surface X-ray scattering data that a small amount of oxygen-containing species (unspecified) and/or ClO 4 -are adsorbed on Pt(111) immersed in 0.1 M HClO 4 at 0.57 VRHE within the double-layer region. Though I have assumed Had and OHad as the chemisorbates when explaining the experimental data of Ojha et al., the existence of other chemisorbates such as ClO 4 -and organic impurities cannot be excluded for this moment.