Nature Chemistry 1, 397–402 (2009); published online: 20 July 2009; corrected after print: 23 August 2010.

In the version of this Article originally published, the descriptions about data analysis of the electrocatalysis in the Methods section were incorrect; the corrected section is shown below. This has been corrected in the HTML and PDF versions of the Article.

CO is the concentration of O2 in the electrolyte solution under pure O2 at atmospheric pressure (1.2 × 10−6 mol cm−3), DO is the diffusion coefficient of O2 (2.0 × 10−5 cm2 s−1), ω is the electrode rotation rate (rad s−1), and ν is the kinematic viscosity of water (1.0 × 10−2 cm2 s−1); the physical constants are from ref. 41.