Vertically Aligned Cu-Doped ZnO Nanorods for Photocatalytic Activity Enhancement

This paper reports the synthesis and characterization of Cu-doped ZnO nanorods with enhanced photocatalytic activity in degrading industrial wastewater contaminations. Arrays of the doped nanorods are grown in the precursor solution using a hydrothermal process at various growth durations and Cu contents (1% to 15% mol). Results of the synthesis process are analyzed using finite element scanning electron microscopy (FESEM), energy dispersive X-ray analysis (EDAX), X-ray diffraction (XRD), and Raman spectroscopy. The optical properties of the photocatalyst are analyzed using photoluminescence and UV-Vis analyses. EDAX spectra of the synthesized nanorods confirm the presence of Zn, O, and Cu. The XRD patterns show the typical hexagonal ZnO in the (0 0 2) plane. Meanwhile, FESEM images show the vertically aligned nanorods in which the geometries of the structure depend on the growth time. In addition, Cu doping on ZnO affects the physical dimension of the rod structure and the optical properties of the ZnO nanorods. Compared with pristine ZnO, the ZnO/Cu nanorods have approximately 44% shorter length and approximately 36% higher diameter. The Cu doping also enables photon absorption in the visible light spectrum to improve photocatalytic activity. Photocatalytic degradation test results show that the highest methylene blue reduction of 97% is obtained using ZnO nanorods doped with 4 mol% Cu under 30 W UV exposure. The developed photocatalyst system could improve human health and environmental quality.