Facile fabrication of Zn-doped CuAl₂O₄ nanofiber membranes for photocatalytic degradation of dye wastewater

Zinc-doped CuAl₂O₄ (Zn-CuAl₂O₄) nanofiber membranes with a high specific surface area, multi-pore structure, and a partial inverse spinel structure were successfully fabricated by controlling the electrospinning process and calcination atmospheres. The excessive doping of Zn²⁺ ions results in the formation of ZnAl₂O₄/CuAl₂O₄ fiber membrane, which has a poor UV-Vis absorption ability. The diameter of Zn-CuAl₂O₄ nanofibers is about 80 nm, and the specific surface area of the Zn-CuAl₂O₄ nanofiber membrane is 45.2 m²/g. XRD and XPS results indicate that Zn-CuAl₂O₄ nanofiber membranes contain spinel and inverse spinel phases. Compared with pure spinel CuAl₂O₄ nanofiber membranes, the UV-Vis absorption ability of the Zn-CuAl₂O₄ nanofiber membrane is enhanced, and transient photocurrent intensity was increased from 0.14 mA/cm² to 0.16 mA/cm². The free radical capture experiments and EPR spectra indicate that huge ·O₂⁻ are generated on the surface of the Zn-CuAl₂O₄ nanofiber membrane, and the photocatalytic degradation efficiency of MB is increased by 14%. The Zn-CuAl₂O₄ nanofiber membranes exhibit excellent cycling stability and have great potential for photocatalytic degradation of dye wastewater.