Room-Temperature Preparation of Cobalt-Based Electrocatalysts through Simple Solution Treatment for Selectively High-Efficiency Hydrogen Evolution Reaction in Alkaline or Acidic Medium

Figure 6

(a) LSV polarization curves for HER and (b) the corresponding Tafel slopes of bare Ni Foam, Co-Pi/CoP/NF, and Pt sheet in 0.5 M H₂SO₄ (pH = 0). (c) Chronoamperometry curves of the long-term stability of the Co-Pi/CoP/NF electrode at a static overpotential of 112 mV in 0.5 M H₂SO₄. (d) Polarization curves obtained over Co-Pi/CoP/NF before and after potential sweeps between −0.2 and +0.2 V vs. RHE for 3000 cycles with a scan rate of 0.1 V/s.

(a)

(b)

(c)

(d)