Vertically Aligned ZnO@ZnS Nanorod Chip with Improved Photocatalytic Activity for Antibiotics Degradation

Abstract

The photocatalytic degradation for environmentally hazardous substances has been widely explored with the use of various photocatalysts and techniques. It still remains a challenge to achieve efficient degradation and removal of residual antibiotics in the water environment. Here, we report an improved photocatalytic activity chip for degradation of antibiotic tetracycline hydrochloride by perpendicular ZnS-coated ZnO nanorod arrays (ZnO@ZnS NAs). The enhanced photocatalytic activity contributed to the polycrystalline ZnS shell’s effective inhibition of the recombination of photogenerated electron–hole pairs. Meanwhile, vertically aligned ZnO@ZnS nanorod arrays can increase the light harvesting ability by enhancing scattering of light among ZnO@ZnS NAs. On the basis of these findings, an improved photocatalytic activity ZnO@ZnS NA chip has been fabricated by growth of ZnO NAs on a piece of silicon wafer and further sulfurization. More importantly, ZnO@ZnS NA chips have been utilized to construct a ladderlike device, purifying antibiotics wastewater in one step, to effectively degrade tetracycline hydrochloride with enhanced photocatalytic efficiency in flowing contaminated water. In addition, the ZnO@ZnS NA device exhibited excellent recyclability in multiple repeated cycles. The ZnO@ZnS NA chip provided a convenient and fast strategy for removal of antibiotics and pharmaceutical residues in wastewater.