Thiebaud, J., Thévenet, F., & Fittschen, C. (2010). OH radicals and H2O2 molecules in the gas phase near to TiO2 surfaces. The Journal of Physical Chemistry C, 114(7), 3082-3088.
The formation of OH radicals and their diffusion into the gas phase after UV-excitation of TiO2 in the presence of H2O has been studied using the very sensitive and selective detection method of laser-induced fluorescence (LIF). The time-resolved evolution of the OH radical concentration has been observed at different pressures and at varying distances between the photocatalytic surface and the detection volume. H2O2 has been indirectly detected by LIF. The influence of O2, hydrocarbons, and excitation laser wavelength on the evolution of both species profiles has been studied in this work. The quantum yield for the formation of OH and H2O2 has been estimated by comparison with signals obtained after photolysis of H2O2 in the gas phase.