With further decreasing potential, the H 2 O 2 current then increases again slowly. A more detailed inspection resolves an additional minimum in this region, which seems to coincide with the sharp peak at about 0.0 V (between regions IIIc and IVc in the BCV). In this peak, the remaining *OH is reductively removed from the surface, concomitant with the adsorption of atomic hydrogen (*H) and the onset of the HER. The increasing presence of *H species activates slow H 2 O 2 formation down to the lower potential limit.