Fig. 4
From: Hydrogen production from water electrolysis: role of catalysts
A Schematic illustration of the mechanism of HER on nanometer-scale Ni(OH)2 clusters on Pt electrode surface (Figure reprinted with permission from Ref. [48]). B (a) Schematic illustration of the transformation of PtNi/C to PtNi–O/C via annealing in air, and (b) comparison of HER mass activities at − 0.07 V vs RHE (Figure reprinted with permission from Ref. [36])