Fig. 2. Electrochemical performance of Co₃Sn₂S₂ single-crystal catalyst.

(A) OER polarization curves for Ni foam, Co₃Sn₂S₂ single crystal, and Co₃Sn₂S₂ micropowder crushed from the single crystal. (B) Overpotential of Co₃Sn₂S₂ single-crystal catalyst at 10 mA cm⁻² compared with some recently reported results for OER electrocatalysts. (C) Tafel plot of Ni foam, Co₃Sn₂S₂ single crystal and Co₃Sn₂S₂ micropowder Koutecky-Levich plots in O₂-saturated 1 M KOH solution. The wide linear regime indicates the excellent electron transfer kinetics even at large overpotential. RHE, reverse hydrogen electrode. (D) Multicurrent process with the current density increased from 10 to 85 mA cm⁻² without iR correction.