Lateral Depletion of Contact to Metallic Nanoparticles on Boron-Doped Diamond Electrodes

A lateral depletion of contact to metallic nanoparticles on semiconducting diamond electrodes was analyzed by a two-dimensional numerical simulation.The theoretical analysis was applied to experimental results on single-crystal diamond electrodes with an oxygen-terminated surface decorated by gold nanoparticles of 15 and 50 nm size ranges, tested in 0.1 M H 2 SO 4 .According to the proposed model, a surface depletion of diamond in electrolytes may penetrate sidewise under the contact to the nanoparticles by decreasing the potential of p-type electrode.Due to this effect the contact area could eventually be pinched off, which leads to a shift of the electrochemical reactions at the particles to more negative potentials or to their complete suppression.A good correlation was found between the simulation results and the characteristics of the decorated electrodes with different size nanoparticles and different boron doping concentrations in the surface layer.