The effect of dark recovery time on the photoefficiency of heterogeneous photocatalysis by TiO2 suspended in non-aqueous media

Variation of dark recovery time influences the efficiency of a heterogeneous photocatalytic oxidation on irradiated TiO₂ particles suspended in non-aqueous media, but does not affect the efficiency of a parallel photocatalyzed reduction. The efficiency of the photocatalyzed oxidation of 1-octanol on Degusa P-25 TiO₂ in oxygenated acetonitrile nearly doubled when the dark interval between excitation pulses was increased from 0.1 s to 1 s. No improvement in photoefficiency could be detected in the photocatalytic reduction of p-nitroacetophenone under the same conditions.