Cadmium atomic layers on tellurium electrodes

The process of electrodeposition of atomic layers of cadmium Cd-ad at order of magnitude polycrystalline tellurium electrodes at potentials in excess of equilibrium potential ECd2+/Cd (underpotential deposition, UPD) is studied. In acid sulfate solutions (0.1 M H2SO4 + 0.05 M CdSO4), the magnitude of underpotential (underpotential shift) Delta E-UPD = 0.41 V. In cyclic voltammograms, the anodic oxidation of Cd-ad is recorded in the form of two peaks of anodic current that are displaced relative to one another in the potential scale (weakly and strongly bound adatoms). The cadmium UPD process on tellurium is accompanied by the diffusion of cadmium into the bulk of tellurium and a transition from a 2D structure Cd-ad/Te to 3D CdTe nanostructures, which are distributed in the tellurium matrix. In contrast with tellurium, the Te/CdTenano heterostructure exhibits photoelectrochemical activity, i.e. it generates a cathodic photocurrent.