Fig. 3: Correlation of catalytic performances with active oxygen species.
a–c Tafel plottings of a Fe, Ni, and Co, b Ag, Cu, and Au, and c Ti, Sn, and Nb foils before and after FeOxHy decoration; d Tafel slopes dependent on active oxygen species. The metal foils with superoxide groups (–OO−) and peroxyl groups (–OOH) are highlighted with orange and blue backgrounds, respectively. The metal foils without any active oxygen species are highlighted with a light gray background. The Tafel slopes of Ni and Co at low overpotential regions were probed from the corresponding metal foams and are highlighted with a dark grey background; e OER onset potentials plotting against the emerging potentials of active oxygen species. M(O)OH and FeOxHy@M(O)OH are highlighted with gray and orange backgrounds, respectively. Ti, Sn, and Nb were not shown because there are no active oxygen species on them. Standard errors for Tafel slopes were calculated from the standard deviations from three measurements. Standard errors for onset potentials were calculated from the potential step in in-situ Raman analysis. Source data are provided as a Source Data file.
