The effect of support on the structure and photocatalytic activity of ternary ZnO-ZnFe2O4/palygorskite composite photocatalysts

The ternary ZnO-ZnFe₂O₄/palygorskite composite photocatalysts were fabricated via a solvothermal method followed by thermal treatment. The structure, morphology and photoelectric performances of samples were characterized, and the results indicated that ZnO/ZnFe₂O₄ nanoparticles with size of 25–30 nm were adequately anchored on the palygorskite fibers surface. Compared with ZnO, ZnFe₂O₄, ZnO/ZnFe₂O₄ and ZnO/palygorskite, the ZnO-ZnFe₂O₄/palygorskite composite photocatalysts exhibited significantly improved photocatalytic activity in degradation of methylene blue (MB). Especially, the optimal photocatalyst (ZF1.5) displayed the highest photocatalytic activity, achieving 99.68% and 99.48% degradation efficiency after 90 min of UV–vis (350 ≤ λ ≤ 780 nm) and 100 min of visible-light (λ ≥ 420 nm) irradiation, respectively. The photocatalysis degradation process matched well with the Langmuir-Hinshelwood kinetics. The obtained improvement of photocatalytic activity was ascribed to the synergetic effect of superior visible-light utilization; effective charge carrier separation and palygorskite support effect (optimize nanoparticles dispersibility, developed mesoporous structure, enlarge specific surface area and increase adsorption capacity).