Light-induced oxidative transformation of diphenylamine on ZrO2. Synergism by ZnO and ZnS

Abstract

Diphenylamine (DPA) in ethanol on the surface of ZrO2 undergoes photoinduced oxidative transformation yielding N-phenyl-p-benzoquinonimine (PBQI). The light-induced transformation on ZrO2 enhanced with DPA concentration, ZrO2-loading, airflow rate and photon flux. The formation of PBQI on ZrO2 is larger on illumination at 254 nm than at 365 nm. The ZrO2 is reusable without any treatment. The mechanism of light-induced oxidative transformation of DPA on ZrO2 is discussed with an appropriate kinetic law. ZnO and ZnS enhance the UV light-induced transformation of DPA on ZrO2, indicating synergism.