c(HClO4) / mol L-1 Pot vs. RHE / mV d Pot vs. RHE / mV 0.1 -3.030 1.170 0.25 -2.950 1.100 0.5 -3.130 0.680 1 -3.615 0.015 2 -3.525 0.475 3 -3.610 0.410 4 -3.465 0.335