Preparation And Photocatalytic Properties Of ZnO/CuO Composite Nano Materials

Since the environmental problems relating to organic and toxic waste in water endangered human health and inhibited economic development, photocatalysis as an efficient and environmental-friendly way to manage water pollution has received extensive attention in recent years. Nowadays semiconductor materials have been widely used in photocatalytic fields due to their outstanding catalytic activity. Among many semiconductor materials, ZnO becomes a very promising candidate for applications in photocatalysis because of its superior properties such as high photocatalytic activity, easy synthesis, low cost and non-toxicity.In this article ZnO nanorods(NRs) material is successfully synthesized by sputtering- hydrothermal method. X-ray diffraction(XRD) and scanning electron microscopy(SEM) show ZnO NRs material has a typical hexagonal structure with flat top and smooth surface. All nanorods are thin and long with uniform diameter from head to end and have high crystalline quality. And it is found that seed layer plays a vital role during the preparation of ZnO NRs. Furthermore, the photocatalytic activity is investigated by degradation of methyl orange in aqueous solution. The result shows that ZnO NRs material has a certain photocatalytic activity. ZnO NRs are successfully synthesized on CuO thin film by hydrothermal method. The result of scanning electron microscopy demonstrates that the ZnO NRs produces great changes on morphology after composed with CuO thin film. The current-voltage measurement of ZnO NRs/CuO film heterostructures shows an evident rectifying behavior. It can be obviously seen that after composed with CuO thin film, the ZnO NRs became slim and uniform with the diameters. Moreover, every dozens of ZnO NRs were overlapped with each other and all tops of ZnO NRs were reunited into clusters forming like-tower structures. Optical absorption capacity ZnO NRs/CuO film heterostructures extends to the visible region, which shows a greater degree of improvement than the intrinsic ZnO NRs. I-V measurement of ZnO NRs/CuO film heterojunctions exhibits the typical diode rectifying characteristic and as expected, ZnO NRs/CuO film heterostructures exhibited higher photocatalytic activity than ZnO NRs. In addition, ZnO NRs/CuO nanosheets(NS) material is successfully synthesized by photodeposition. CuO were coated on the surface of ZnO NRs in the form of nanosheet. Most of CuO are square sheet structures, grow to different orientation, covering cross-cutting, surface flat and edges smooth. The absorption of ZnO NRs/CuO NS shows apparently red shit compared with that of instinct ZnO NRs. Heterostructures are also formed between ZnO NRs and CuO NS. The forming process of CuO NS goes from fluff to gathers into a transparent sheet gradually, and finally grows into opaque, uniform thick sheets. It also overcomes the disadvantages of the intrinsic ZnO used as a photocatalyst and the photocatalytic activity of ZnO NRs/CuO NS has been significantly improved compared with ZnO NRs.