Near Ultraviolet and Visible light photoelectrochemical degradation of organic substances producing electricity and hydrogen

A two-compartment, chemically biased photoelectrochemical cell was used to photodegrade several organic substances and produce electricity and hydrogen. The photoanode of the cell was based on commercial nanocrystalline titania, which may be functionalized with CdS to absorb Visible light. The dark cathode was made also of commercial nanocrystalline titania with cast Pt nanoparticles. The cell was run under Near Ultraviolet or Visible radiation and the efficiencies in the two cases have been compared. Short chain-length alcohols and glycerol produced the highest energy yield but water-soluble waste materials are also interesting for the same purpose. The overall efficiency of cells made by CdS-functionalized titania was higher than those made of pure titania. However, larger currents were obtained with pure TiO2 under Near Ultraviolet excitation. Under anaerobic conditions, molecular hydrogen can be produced at the dark cathode by the reduction of hydrogen ions generated at the photoanode.