Surface Modification of Tetrapod-Like ZnO Whisker by Cuprous Oxide and Its Photocatalytic Properties
Cu2O/T-ZnOw composite catalysts were prepared by a simple liquid-phase reduction method,in which ethylene glycol(EG)as reducing agent and polyvinyl pyrrolidone(PVP)as surfactant.The phase,morphology,band gap,photoluminescence properties,photodegradation,and recyclable performance of samples were studied in detail.The result shows that PVP plays an important role in the morphology of Cu2O.It makes Cu2O crystals deposited on the surface of tetrapod-like ZnO whiskers(T-ZnOw)gradually transformed from cubic to sphericity.When Cu2O crystals deposited on T-ZnOw surface,the band gap(Eg)of semiconductor catalysts were narrowed,and the recombination of photogenerated electron and hole pairs were effectively reduced,which can significantly improve the photocatalytic activity of semiconductor.The degradation efficiency of methyl orange(MO)solution by composite catalysts is increased to more than 90%after 100 min UV irradiation.At the same condition,the cubic-Cu2O/T-ZnOw composite shows higher photocatalytic activity than spherical-Cu2O/T-ZnOw.After six recycles of photocatalytic degradation tests,the degradation rate of samples prepared by 0.06 g PVP can still be maintained more than 80%,which shows that the Cu2O/T-ZnOw composites have good recyclable performance.