Time scales and pH dependence of the redox processes determining the photocatalytic efficiency of TiO2 nanoparticles from periodic illumination experiments in the stochastic regime

The photochemical experiments under periodic illumination in the stochastic regime reveals two rate-determining intermediates having different lifetimes with opposite pH dependences. The reducing species becomes more active at higher pH, the converse being valid for the oxygen carrier, as a result of the shift in the electrical potential of TiO2 particles.