A facile wet chemical route to prepare ZnO/TiO2 nanotube composites and their photocatalytic activities

Abstract

Highly dispersed ZnO/TiO2 nanotube composites (NTCs) were successfully synthesized by a facile ethylenediamine-assisted deposition-precipitation route. The characterizations from x-ray diffraction, x-ray photoelectron spectroscopy, transmission electron microscopy, Brunauer–Emmett–Teller, Fourier transform infrared, and ultraviolet-visible spectra revealed that hexagonal wurtzite phase ZnO NPs with an average size of about 2 nm were homogeneously dispersed and anchored on the surface of TiO2 nanotubes (NTs) to form ZnO/TiO2 NTCs. The as-prepared ZnO/TiO2 NTCs with the atom ratio Zn/Ti of 1:4 exhibited excellent photocatalytic activity for photodegradation of methyl orange compared with P25 and pure TiO2 NTs, which were mainly caused by an increase of interfacial charge transfer reactions and a decrease of electron-hole pair recombination on ZnO-TNTs heterojunction. Furthermore, ZnO/TiO2 NTCs possessed favorable recycle efficiency due to their relatively high sedimentation rate and only a slight decrease of photocatalytic activity after a six time recycle.