Visible-light-induced mesoporous ZnO hexagonal sheets decorated by CuAl2O4 nanoparticles for accelerating removal of tetracycline

초록

The photocatalytic ability of bare ZnO is less sufficient owing to a weak separation rate of electron-hole and weak exploitation of solar energy. In this context, mesoporous ZnO nanosheets were constructed through a hydro-thermal approach utilizing hexadecyltrimethylammonium bromide (HTAB) as a template. Then, CuAl2O4 NPs at different concentrations were grown in-situ onto mesoporous ZnO nanosheets to build mesoporous CuAl2O4/ZnO photocatalysts. XRD and TEM indicated the formation of the spinel cubic CuAl2O4 (10 nm) with uniform distribution on the hexagonal structure of ZnO sheets. The synthesized CuAl2O4/ZnO nanocomposites were assessed for tetracycline (TC) photodegradation under visible illumination. The optimal p-n heterojunction 12%CuAl2O4/ ZnO photocatalyst revealed excellent photocatalytic efficiency of 100 % after 90 min for TC degradation. The 12%CuAl2O4/ZnO nanocomposites showed the optimum rate constant of 0.0739 min-1, which was about 49.75 folds larger than that of bare ZnO (0.0015 min-1). The superior photocatalytic activity of CuAl2O4/ZnO nano-composite was interpreted by its excellent harvest of visible light, synergistic effects, mesopores structure characteristics, effective separation of photocarriers, larger surface area, smaller particle size, proper bandgap energy, and larger pore volume. The stability and reusability of the photocatalyst showed superior photocatalytic ability (94 %) during five consecutive cycles. This work provides the design novel of p-n heterojunction-based photocatalyst to be a valuable reference for photocatalytic degradation systems.

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