Substituent effect on nano TiO2‐ and ZnO‐catalyzed phenol photodegradation rates

Photodegradation of phenol on TiO2 P25 Degussa, TiO2 Hombikat, TiO2 anatase, and ZnO nanoparticles exhibits identical photokinetic behavior. The degradation rates of 15 ortho‐, meta‐ and para‐ substituted phenols on the four semiconductor nanocrystals do not conform to the electronic effect of the substituents but show some common features. While the orthosubstituents slow down the reaction, nitro and hydroxyl groups enhance the same. The effects are rationalized.