Effect of Pt layers on the photoelectrochemical properties of a WO3/p-Si electrode

Abstract

The effect of Pt deposition on the photoelectrochemical properties of a WO 3 /p- Si electrode was studied with regard to hydrogen evolution, photocurrent transient, and chemical stability. Deposition of Pt layers made it possible for photocurrent onset potential to be shifted to a more positive value and both the photocurrent density and hydrogen evolution rate were increased. These phenomena can be explained by the fact that Pt loading decreases the overpotentials in the reduction reaction at the electrode/electrolyte interfaces to make electron transfer faster, as well as decrease the recombination rate of carriers. The influences of the Pt layer were confirmed by investigating the photocurrent transient behaviors. In the case of the Pt/WO 3 /p- Si electrode, particularly high quantum efficiencies were obtained in a wavelength range of 430–700 nm, possibly due to inelastic electron–electron scattering. The Pt/WO 3 /p- Si electrodes did not show any detectable corrosion after illumination for 5 h according to the observation of surface microstructures.