Hydrogen Evolution from Pt Nanoparticles Covered p-Type CdS:Cu Photocathode in Scavenger-Free Electrolyte

The photoelectrolysis of water to generate hydrogen by semiconductor photoelectrodes has been known to be a promising approach to utilize clean and sustainable solar energy. In this study, photocathode based on p-type CdS:Cu was successfully fabricated by the thermal evaporation process and photoelectrochemical investigations were carried out to determine its water photoelectrolysis potential. Cu doping concentration at 5.4% was found to be the optimal doping level and the bare CdS:Cu photocathode showed a large transient photoinduced electrons at the photoelectrode/electrolyte interface. The photocurrent as a result of the slow water reduction kinetics of the electrons accumulated at the interface and caused the photocathode to suffer from photodegradation during the stability test. After modifying the photocathode surface with the Pt nanoparticles to reduce the hydrogen evolving reaction overpotential, both the photocurrent and stability were enhanced. Hydrogen evolution from the CdS:Cu/Pt surface in the near neutral and scavenger-free electrolyte demonstrated for the first time the CdS with p-type conductivity was a feasible candidate for solar water splitting.