Peroxodisulfate reduction has been investigated on Pt(111) on a broad range of pH values as a way to test interfacial charge. The reaction always proceeds in a potential window that is almost pH independent, regardless of changes in the presence of adsorbed species. Comparison with other available information for these interphases allows to conclude that this reaction is very sensitive to the free charge on the metal, being inhibited when the latter is negative. This explains the complete current inhibition when the potential is lower than the potential of zero free charge. Most remarkably, the inhibition at high potentials can be related to the existence of a second potential of zero charge, above which the surface becomes again negatively charged. This conclusion agrees with classical results for polycrystalline platinum (which has been reexamined), results from laser induced T-jump experiments and recent theoretical models of the interphase. In this way, this reaction is postulated as a new probe to locate the values of the potential of zero free charge.

已在广泛的pH值范围内对Pt（111）进行过二硫酸盐还原的研究，以此作为测试界面电荷的方法。无论吸附物种的存在如何变化，反应总是在几乎不受pH值影响的潜在窗口中进行。与这些中间相的其他可用信息进行比较可以得出结论，该反应对金属上的自由电荷非常敏感，当金属为负时会受到抑制。这解释了当电势低于零自由电荷的电势时完全的电流抑制。最显着的是，在高电势下的抑制作用可能与存在零电荷的第二电势有关，在第二电势之上，表面再次变为负电。该结论与多晶铂的经典结果（已被重新检验），激光诱导的T跃实验和最近的相间理论模型相吻合。以这种方式，该反应被假定为新的探针，以定位零自由电荷的电势的值。