Preparation and photothermal performance study of CuS@PDA/MoS₂/polylactic acid nanofiber membranes

CuS@PDA/MoS₂ (PDA = polydopamine) composite photocatalytic nanoparticles with highly efficient synergistic natural light/heat conversion have been prepared by hydrothermal reaction. In the first step, CuS@PDA nanoparticles with a core-shell structure were obtained by in situ oxidative polymerization of dopamine on the surface of CuS nanoparticles. In the second step, MoS₂ nanoparticles were generated in situ on the surface of the CuS@PDA nanoparticles by thermal reaction. The nanoparticles were characterized by SEM, TEM, XRD and XPS, which confirmed that CuS@PDA/MoS₂ nanoparticles with a three-layer structure had been successfully synthesized. CuS@PDA/MoS₂/PLA (PLA = polylactic acid) photocatalytic nanofiber functional membranes were fabricated by solution electrospinning, and their filtration and photocatalytic performance were investigated. It was found that the addition of CuS@PDA/MoS₂ photocatalytic nanoparticles significantly improved the natural light and heat conversion of polylactic acid fibers. Under irradiation by 1 kW/m² simulated natural light, the temperature rise of the polylactic acid fiber membrane after addition of 5% CuS@PDA/MoS₂ photocatalytic nanoparticles was 9.2 ℃ higher than that of the pure polylactic acid fiber membrane, and the filtration efficiency of the fiber membrane retained 96% of its original capacity after four weeks of tracking tests. The efficiency retention rate of the polylactic acid fiber membrane after the addition of 5% filler was 99.29%, which was higher than that of the pure polylactic acid fiber membrane (98.12%).