It is demonstrated, for the first time using simple cyclic voltammetry experiments, that the anodic pre-polarization of boron-doped diamond electrodes (BDD) leads to partially blocked surfaces. Anodically pre-polarized BDD electrodes, with different boron-doping levels, presented sigmoidal cyclic voltammetry profiles to the ferro/ferri-cyanide redox couple under low scan rate (0.5 mV s-1). On the other hand, when the same electrodes are cathodically pre-polarized, quasi-reversible and reversible responses were observed under the same scan rate, corresponding to surfaces with heterogeneous electroactivity. Thus, BDD surfaces can act as partially blocked or with heterogeneous electroactivity, depending on the polarization, anodic or cathodic, respectively.
surface termination; anodic polarization; cathodic polarization; spherical diffusion; cyclic voltammetry
