Role of Methanol Sacrificing Reagent in the Photocatalytic Evolution of Hydrogen

The contribution of methanol (CH3OH) sacrificing reagent to the photocatalytic evolution of H2 from aqueous solutions has been studied by tracing the reaction of D2O over a Cu/S-TiO2 catalyst under UV illumination. Use of D2O/CH3OH produced higher formation rates of HD and D2 than that of H2. The low H2 formation rates indicate that the direct reaction of CH3OH with photogenerated holes does not proceed to an appreciable extent in the presence of high concentrations of D2O. The role of CH3OH in accelerating hydrogen formation can be attributed to its ability to produce an electron donor, injecting its electrons to the conduction band.