Rhenium electrodeposition process onto p-Si(1 0 0) and electrochemical behaviour of the hydrogen evolution reaction onto p-Si/Re/0.1 M H₂SO₄ interface

In this study we examined the rhenium electrodeposition process onto p-Si(1 0 0). The study was carried out by means of cyclic voltammetry (CV) and the potential-steps method from which the corresponding nucleation and growth mechanism (NGM) were determined. Both methods were performed under illumination for electron photogeneration. A 3D progressive nucleation, diffusion-controlled growth of rhenium films was found (PN3D_Diff). Furthermore, the photocurrent-time transients were fitted with an equation that takes into account redox reactions occurring simultaneously on the rhenium film surface, in this case proton reduction. Likewise, a morphologic analysis was completed for the deposits obtained at different potential values by means of atomic force microscopy (AFM). Finally, the hydrogen evolution reaction, HER, on different electrode systems was studied. An overpotential decrease of 0.2 V and a photocurrent increase by one order of magnitude for the HER on p-Si(1 0 0)/Re electrode system compared with p-Si(1 0 0) and metallic Re was found. According to these effects, this electrode system could be a photoelectrocatalyst for the HER.