Role of Methanol Sacrificing Reagent in the Photocatalytic Evolution of Hydrogen

The contribution of methanol (CH 3 OH) sacrificing reagent to the photocatalytic evolution of H 2 from aqueous solutions has been studied by tracing the reaction of D 2 O over a Cu/S-TiO 2 catalyst under UV illumination. Use of D 2 O/CH 3 OH produced higher formation rates of HD and D 2 than that of H 2 . The low H 2 formation rates indicate that the direct reaction of CH 3 OH with photogenerated holes does not proceed to an appreciable extent in the presence of high concentrations of D 2 O. The role of CH 3 OH in accelerating hydrogen formation can be attributed to its ability to produce an electron donor, injecting its electrons to the conduction band.