Synergistic Li- and Al-co-doped ZnO/CNT hybrid for photocatalytic degradation and dye-sensitized solar cells
摘要
The rapid dispersal of industrial effluents and pharmaceutical pollutants into water sources, together with the rising need for clean energy, prompted an urgent demand for multifunctional materials with the capacity to simultaneously address environmental remediation and solar energy conversion. This study synthesized ZnO, ZnO/CNT, Li-ZnO/CNT, and LiAl-ZnO/CNT nanostructures using a straightforward hydrothermal approach and examined their efficacy for dual photocatalytic and dye-sensitized solar cell (DSSC) applications. X-ray diffraction (XRD) validated the formation of the hexagonal wurtzite ZnO structure, with the crystallite size decreasing from 32 nm for pristine ZnO to 20 nm for LiAl–ZnO/CNT. The UV–Vis diffuse reflectance spectroscopy demonstrated that the band gap energy was decreased from 3.21 to 2.84 eV, indicating the visible-light absorption was increased following CNTs integration and Li/Al co-doping. The LiAl-ZnO/CNT photocatalyst exhibited 96% ciprofloxacin degradation in 90 min with an apparent rate constant of 0.034 min−1 under natural sunlight irradiation. As a DSSC photoanode, LiAl-ZnO/CNT achieved a maximum power conversion efficiency of 7.4%, exceeding pure ZnO (4.7%). The improved multifunctional performance is due to the synergistic effects of Li/Al co-doping and the conductive CNT network, which improve visible-light harvesting, facilitate charge separation and electron transport, and decrease charge-carrier recombination. These findings show that the LiAl-ZnO/CNT hybrid is a promising multifunctional material for renewable wastewater treatment and solar energy conversion.