Fig. 1
Schematic model of the catalyst preparation process and metal size-dependent charge transfer. PtSA/S–C and PtNC/S-C were prepared by wet-impregnation of chloroplatinic acid on the S–C supports followed by H2-reduction at 300 and 700 °C, respectively. When Pt size increases from single-atom to nanocluster, the electron transfer direction is reversed, resulting in greatly enhanced activity for catalyzing HER
