In light of the important role of R8 as the RDS for ORR on Pt(111) and the significant higher equilibrium potential of R8 on Au(100) (~1.2 V RHE) than that on Pt(111) (~1.0 V RHE), it is worthwhile to re-examine their respective current(j)electrode potential (E) curves, as shown in Figure . In the 0.9 < E < 1.0 V (RHE) region, the ORR currents on Pt(111) and on Au(100) are nearly the same (Figure ). However, in 1.0 < E < 1.18 V, there is still a small cathodic current on Au(100) (Figure ). There are two complicating factors in this region: a significant double layer charging current and a significant pseudo-capacitive current due to the formation/reduction of Au oxide. The latter current, due to the presence of Au oxide during previous positive scans, produced a small cathodic peak ca 1.05 V, superimposed on the j-E curve for the alkaline ORR on Au(100), as reported in two independent studies. The presence of small ORR current in 1.0 < E < 1.18 V region has therefore not been carefully examined before. To eliminate the double layer charging current, we have subtracted the j-E curve measured in Ar saturated solution from the ORR (O2 saturated) j-E curve. To eliminate the Au oxide reduction current, we use the data obtained only from positive scans. The corrected j-E shows a small cathodic current in 1.0 < E < 1.18 V on Au(100), very close to the overall ORR equilibrium potential at 1.23 V (see the blow up in Figure ).