Hydrogen Production and Photodegradation at TiO2/Metal/CdS Sandwich Using UV–Visible Light

The synthesis and characterization of a metal (M = Pt, Au, or Ag) sandwiched with CdS and in-house TiO2 (IH-TiO2) have been summarized. When compared to commercial Degussa P25® TiO2, the IH-TiO2 showed 100 % anatase content, more than twice the active surface area and superior photoelectrochemical responses (charge separation and potential). This composite/sandwich has been tested for photocatalytic hydrogen production in the presence of sacrificial agents and UV–visible light. Typical traditional sacrificial agent—polysulfide—toward photocatalytic hydrogen production has been examined. Moreover, a representative dye pollutant such as (methyl orange (MO)) instead of polysulfide also demonstrated hydrogen production. The simultaneous pollutant degradation and hydrogen generation have been recognized from absorbance and chromatographic analyses. A complete analysis of the hydrogen generation rate (per unit mass of catalyst) showed the following trend: IH-TiO2/Pt/CdSpolysulfide > IH-TiO2/Pt/CdSMO > IH-TiO2/Pt/CdSDI-water. A first-order power-law degradation model has been proposed for MO photoconversion.