Laser flash photolysis of titanium dioxide suspensions for the evaluation of solvent-mediated radical reactions.

The chemistry originating from the scavenging of the highly electrophilic hole in TiO2 can be readily monitored using laser flash photolysis techniques. Dilute suspensions are sufficiently transparent in the UV region that long lived signals from reactions of solvent radicals with 1,1-diphenylethylene can be readily monitored. Transient signals originating from hole, electron and trapped radicals are extremely long lived showing stretched exponentials (nanoseconds to milliseconds), adequately described by fractal models.