J. Phys. IV France 09 (1999) Pr3-295-Pr3-299
Influence of photoadsorbed O2 on the photoreduction of CO2 with H2O at the surface of TiO2I. Alxneit and M. Corboz
Paul Scherrer Institute, 5232 Villigen-PSI, Switzerland
The stoichiometry of the CO2 photoreduction using TiO2 (Degussa P25) as photocatalyst in the presence of water vapor was investigated in detail. It was observed that oxygen is missing in significant amounts on the product side and that the efficiency of the reaction decreases with time. Photoadsorption of O2 at TiO2 was investigated as a possible explanation of these facts. It was found that the photoactivity is strongly hindered by photoadsorbed oxygen and ceases completely at a surface coverage of Θ = 0.05. This low value does not allow to attribute all the missing oxygen in the reaction to oxygen photoadsorbed on the photocatalyst. Photoadsorption can therefore not be invoked to explain the fate of the missing oxygen in the reaction products.
© EDP Sciences 1999