Photocorrosion Inhibition and Photoactivity Enhancement for Zinc Oxide via Hybridization with Monolayer Polyaniline

Monomolecular-layer polyaniline (PANI) was dispersed on the surface of zinc oxide (ZnO) and formed the hybrid effect between ZnO and PANI. The hybrid photocatalysts showed dramatic photocatalytic activity for the degradation of the methylene blue (MB) both under ultraviolet and visible light irradiation, and the photocorrosion of ZnO was successfully inhibited. The enhanced photocatalytic activity for PANI-hybridized ZnO originated from the high separation efficiency of photogenerated electrons and holes on the interface of PANI and ZnO, which was produced by the hybrid effect of PANI and ZnO. The photocorrosion inhibition of ZnO could be attributed to the rapidly transferring of photogenerated holes by the PANI monolayer. The relationship between the PANI content of the samples and their photocatalytic performance shows that an optimal PANI weight percent (1.0%) can significantly enhance the photocatalytic efficiency and anticorrosion of ZnO particles. In particular, the mechanisms on the enhancement of photocatalytic activity and anti photocorrosion performance have been emphasized. Under ultraviolet light irradiation, photogenerated holes in the ZnO valence band could transfer to the. HOMO orbital of PANI and then emigrate to the photocatalysts surface and oxidize the adsorbed contaminants directly. Under visible light irradiation, PANI generated a pi(-)pi* transition, delivering the excited electrons to the conduction band of ZnO, and then the electrons transferred to an adsorbed electron acceptor, yielding oxygenous radicals to degrade pollutants.