Fig. 3: Electrocatalytic performance of Pt-ACs/CoNC and reference HER catalysts.

a HER polarization curves of CoNC, Pt-SAs/CoNC, Pt-ACs/CoNC, Pt-NPs/CoNC and Pt/C with same total loading on the working electrode with same geometric surface area in 0.5 M H2SO4 solution. b Mass activity of state-of-the-art Pt/C, Pt-SAs/CoNC, Pt-ACs/CoNC and Pt-NPs/CoNC at the overpotential of 50 mV with same total loading on the working electrode. c Corresponding Tafel slope. d Comparison of Tafel slope and mass activity for various Pt-based HER catalysts in 0.5 M H2SO4 solution. Values were plotted from references (Supplementary Table 2). e EIS Nyquist plots of CoNC, Pt-SAs/CoNC, Pt-ACs/CoNC and Pt-NPs/CoNC obtained at the overpotential of 20 mV. f Chronoamperometry curve of Pt-ACs/CoNC obtained at the overpotential of 27 mV.