Synthesis of ZnO/Au Nanorods for Self Cleaning Applications

Zinc oxide (ZnO) is a well-known semiconductor with valuable characteristics: wide direct band gap of ˜3.3 eV, large exciton binding energy of 60 meV at room temperature, high efficient photocatalyst, etc. which have been applied in many fields such as optical devices (LEDs, laser), solar cells and sensors. Besides, various low dimensional structures of ZnO in terms of nanoparticles, nanorods, nanoneedles, nanotetrapods find applications in technology and life. This material is also appealing due to the diversity of available processing methods including both chemical and physical approaches such as: hydrothermal, sol-gel, chemical vapor deposition and sputtering. In this report, ZnO nanorods are prepared by hydrothermal method assisted with galvanic-cell effect. The effect of counter electrode materials on the morphology and structure of obtained product was studied. Scanning electron microscopy (SEM) images of the product showed that counter electrodes made of aluminum offers nanorods of higher quality than other materials in terms of uniform size, high density and good preferred orientation. The as-prepared nanorods were then sputtered with gold (Au). ZnO/Au nanostructures show excellent photocatalyst activities which were demonstrated by complete photodegradation of methylene blue (Mb) under UV irradiation and high decomposition rate k of 0.011 min^-1.