Synthesis of N-doped ZnO/ZnCo2O4 composites for stable photocatalytic degradation of organic dyes

Abstract

Based on the ZnCo-layered double hydroxides, the N-doped ZnO/ZnCo2O4 composites were successfully prepared via hydrothermal method. The as-synthesized composites were characterized by X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, Fourier-transform infrared spectroscopy, N-2 adsorption-desorption analysis and UV-vis diffuse reflectance spectroscopy. The results showed that N-ZnO/ZnCo2O4 composites can support abundant oxygen vacancies to build ohmic contact and broaden the wavelength range of light absorption. Moreover, the methylene blue (MB), methyl orange (MO) and rhodamine B (RhB) were selected as the probe molecules to explore the photocatalytic performance of the N-ZnO/ZnCo2O4 composites. It was discovered that the removal efficiencies of MB, MO and RhB were approximately 91.66%, 90.95% and 91.22% within 210 min under visible light irradiation, respectively. The N-ZnO/ZnCo2O4 composites still maintain remarkable reusability and stability for degradation of the above three dyes after five successive cycles. Furthermore, the possible degradation mechanism of the N-ZnO/ZnCo2O4 composites was discussed in this work.