fig1

Figure 1. HER characterization of Co_xRu₁O_x and reference catalysts in 1 M KOH: (A) LSV responses; (B) overpotentials at selected current densities; (C) Tafel plots; (D) C_dl; (E) ECSA; and (F) 200 h chronopotentiometry of Co₄Ru₁O_x at -100 mA cm^-2. (G) HER polarization of Co₄Ru₁O_x in 1 and 6 M KOH, together with Pt/C in 1 M KOH. (H) A 200 h stability trace for Co₄Ru₁O_x at -100 mA cm^-2 in 6 M KOH.