Fig. 2. Electrochemical HER activity of CoP/rGO-400. (a) LSV curves, (c) Tafel slopes and (e) durability test in 0.5 M H2SO4 solution; (b) LSV curves, (d) Tafel slopes and (f) durability test in 1 M KOH solution. Insets in (e and f): time-dependent current density curves under static overpotentials of 105 mV in 0.5 M H2SO4 and 150 mV in 1 M KOH solution, respectively.
