Fig. 3: Electrochemical analysis in 1.0 M KOH and 0.5 M H2SO4.

a, e HER polarization curves of various Pt-SAs/TMDs samples. b, f HER comparison of overpotentials required to achieve a current density of 10 mA cm−2 (black arrow, left axis) and mass activities (normalized by the Pt loading, red arrow, right axis) at −100 mV versus RHE for various Pt-SAs/TMDs samples. c, g Tafel plots derived from the early stage of the corresponding HER polarization curves. d, h Turnover frequency (TOF) curves of various Pt-SAs/TMDs samples and a comparison with the previously reported state-of-the-art values for single-atom HER catalysts.